138 files changed, 3315 insertions, 2065 deletions

diff --git a/packages/contracts/README.md b/packages/contracts/README.md
index 9c829c753..2e6376f39 100644
--- a/packages/contracts/README.md
+++ b/packages/contracts/README.md
@@ -64,11 +64,51 @@ yarn lint
 yarn test
 ```
 
-### Run Tests Against Geth
+#### Testing options
 
-Follow the instructions in the README for the devnet package to start the
-devnet.
+###### Revert stack traces
+
+If you want to see helpful stack traces (incl. line number, code snippet) for smart contract reverts, run the tests with:
+
+```
+yarn test:trace
+```
+
+**Note:** This currently slows down the test runs and is therefore not enabled by default.
+
+###### Backing Ethereum node
+
+By default, our tests run against an in-process [Ganache](https://github.com/trufflesuite/ganache-core) instance. In order to run the tests against [Geth](https://github.com/ethereum/go-ethereum), first follow the instructions in the README for the devnet package to start the devnet Geth node. Then run:
 
 ```bash
 TEST_PROVIDER=geth yarn test
 ```
+
+###### Code coverage
+
+In order to see the Solidity code coverage output generated by `@0xproject/sol-cov`, run:
+
+```
+yarn test:coverage
+```
+
+###### Gas profiler
+
+In order to profile the gas costs for a specific smart contract call/transaction, you can run the tests in `profiler` mode.
+
+**Note:** Traces emitted by ganache have incorrect gas costs so we recommend using Geth for profiling.
+
+```
+TEST_PROVIDER=geth yarn test:profiler
+```
+
+You'll see a warning that you need to explicitly enable and disable the profiler before and after the block of code you want to profile.
+
+```typescript
+import { profiler } from './utils/profiler';
+profiler.start();
+// Some call to a smart contract
+profiler.stop();
+```
+
+Without explicitly starting and stopping the profiler, the profiler output will be too busy, and therefore unusable.
diff --git a/packages/contracts/compiler.json b/packages/contracts/compiler.json
index 6b7b69caa..56c8b1761 100644
--- a/packages/contracts/compiler.json
+++ b/packages/contracts/compiler.json
@@ -24,14 +24,18 @@
         "DummyERC721Receiver",
         "DummyERC721Token",
         "ERC20Proxy",
+        "ERC20Token",
         "ERC721Proxy",
         "Exchange",
         "ExchangeWrapper",
+        "IAssetData",
+        "IAssetProxy",
+        "IValidator",
+        "IWallet",
         "MixinAuthorizable",
         "MultiSigWallet",
         "MultiSigWalletWithTimeLock",
         "TestAssetProxyOwner",
-        "TestAssetDataDecoders",
         "TestAssetProxyDispatcher",
         "TestLibBytes",
         "TestLibs",
diff --git a/packages/contracts/package.json b/packages/contracts/package.json
index 8249b9e0c..e0e82adc7 100644
--- a/packages/contracts/package.json
+++ b/packages/contracts/package.json
@@ -14,17 +14,18 @@
         "watch_without_deps": "yarn pre_build && tsc -w",
         "build": "yarn pre_build && tsc",
         "pre_build": "run-s compile copy_artifacts generate_contract_wrappers",
-        "copy_artifacts": "copyfiles -u 4 '../migrations/artifacts/2.0.0/**/*' ./lib/src/artifacts;",
+        "copy_artifacts": "copyfiles -u 4 '../migrations/artifacts/2.0.0/**/*' ./lib/artifacts;",
         "test": "yarn run_mocha",
         "rebuild_and_test": "run-s build test",
         "test:coverage": "SOLIDITY_COVERAGE=true run-s build run_mocha coverage:report:text coverage:report:lcov",
         "test:profiler": "SOLIDITY_PROFILER=true run-s build run_mocha profiler:report:html",
         "test:trace": "SOLIDITY_REVERT_TRACE=true run-s build run_mocha",
-        "run_mocha": "mocha --require source-map-support/register --require make-promises-safe 'lib/test/**/*.js' --timeout 100000 --bail --exit",
-        "compile": "sol-compiler",
-        "clean": "shx rm -rf lib src/generated_contract_wrappers",
+        "run_mocha":
+            "mocha --require source-map-support/register --require make-promises-safe 'lib/test/**/*.js' --timeout 100000 --bail --exit",
+        "compile": "sol-compiler --contracts-dir src",
+        "clean": "shx rm -rf lib generated_contract_wrappers",
         "generate_contract_wrappers":
-            "abi-gen --abis  ${npm_package_config_abis} --template ../contract_templates/contract.handlebars --partials '../contract_templates/partials/**/*.handlebars' --output src/generated_contract_wrappers --backend ethers",
+            "abi-gen --abis  ${npm_package_config_abis} --template ../contract_templates/contract.handlebars --partials '../contract_templates/partials/**/*.handlebars' --output generated_contract_wrappers --backend ethers",
         "lint": "tslint --project . --exclude **/src/generated_contract_wrappers/**/* --exclude **/lib/**/*",
         "coverage:report:text": "istanbul report text",
         "coverage:report:html": "istanbul report html && open coverage/index.html",
@@ -34,7 +35,7 @@
     },
     "config": {
         "abis":
-            "../migrations/artifacts/2.0.0/@(AssetProxyOwner|DummyERC20Token|DummyERC721Receiver|DummyERC721Token|ERC20Proxy|ERC721Proxy|Exchange|ExchangeWrapper|MixinAuthorizable|MultiSigWallet|MultiSigWalletWithTimeLock|TestAssetProxyOwner|TestAssetDataDecoders|TestAssetProxyDispatcher|TestLibBytes|TestLibs|TestSignatureValidator|TestValidator|TestWallet|TokenRegistry|Whitelist|WETH9|ZRXToken).json"
+            "../migrations/artifacts/2.0.0/@(AssetProxyOwner|DummyERC20Token|DummyERC721Receiver|DummyERC721Token|ERC20Proxy|ERC721Proxy|Exchange|ExchangeWrapper|IAssetData|IAssetProxy|MixinAuthorizable|MultiSigWallet|MultiSigWalletWithTimeLock|TestAssetProxyOwner|TestAssetProxyDispatcher|TestLibBytes|TestLibs|TestSignatureValidator|TestValidator|TestWallet|TokenRegistry|Whitelist|WETH9|ZRXToken).json"
     },
     "repository": {
         "type": "git",
diff --git a/packages/contracts/src/contracts/previous/Arbitrage/Arbitrage.sol b/packages/contracts/src/1.0.0/Arbitrage/Arbitrage.sol
index 5054afc2f..5054afc2f 100644
--- a/packages/contracts/src/contracts/previous/Arbitrage/Arbitrage.sol
+++ b/packages/contracts/src/1.0.0/Arbitrage/Arbitrage.sol
diff --git a/packages/contracts/src/contracts/previous/ERC20Token/ERC20Token_v1.sol b/packages/contracts/src/1.0.0/ERC20Token/ERC20Token_v1.sol
index e05ee2d5e..e05ee2d5e 100644
--- a/packages/contracts/src/contracts/previous/ERC20Token/ERC20Token_v1.sol
+++ b/packages/contracts/src/1.0.0/ERC20Token/ERC20Token_v1.sol
diff --git a/packages/contracts/src/contracts/previous/EtherDelta/AccountLevels.sol b/packages/contracts/src/1.0.0/EtherDelta/AccountLevels.sol
index 8d7a930d3..8d7a930d3 100644
--- a/packages/contracts/src/contracts/previous/EtherDelta/AccountLevels.sol
+++ b/packages/contracts/src/1.0.0/EtherDelta/AccountLevels.sol
diff --git a/packages/contracts/src/contracts/previous/EtherDelta/EtherDelta.sol b/packages/contracts/src/1.0.0/EtherDelta/EtherDelta.sol
index fe599ca0a..fe599ca0a 100644
--- a/packages/contracts/src/contracts/previous/EtherDelta/EtherDelta.sol
+++ b/packages/contracts/src/1.0.0/EtherDelta/EtherDelta.sol
diff --git a/packages/contracts/src/contracts/previous/Exchange/Exchange_v1.sol b/packages/contracts/src/1.0.0/Exchange/Exchange_v1.sol
index 3f8e7368d..3f8e7368d 100644
--- a/packages/contracts/src/contracts/previous/Exchange/Exchange_v1.sol
+++ b/packages/contracts/src/1.0.0/Exchange/Exchange_v1.sol
diff --git a/packages/contracts/src/contracts/previous/Exchange/IExchange_v1.sol b/packages/contracts/src/1.0.0/Exchange/IExchange_v1.sol
index ec4bce7b0..ec4bce7b0 100644
--- a/packages/contracts/src/contracts/previous/Exchange/IExchange_v1.sol
+++ b/packages/contracts/src/1.0.0/Exchange/IExchange_v1.sol
diff --git a/packages/contracts/src/contracts/previous/MultiSigWalletWithTImeLockExceptRemoveAuthorizedAddress/MultiSigWalletWithTimeLockExceptRemoveAuthorizedAddress.sol b/packages/contracts/src/1.0.0/MultiSigWalletWithTImeLockExceptRemoveAuthorizedAddress/MultiSigWalletWithTimeLockExceptRemoveAuthorizedAddress.sol
index 241e02d4a..241e02d4a 100644
--- a/packages/contracts/src/contracts/previous/MultiSigWalletWithTImeLockExceptRemoveAuthorizedAddress/MultiSigWalletWithTimeLockExceptRemoveAuthorizedAddress.sol
+++ b/packages/contracts/src/1.0.0/MultiSigWalletWithTImeLockExceptRemoveAuthorizedAddress/MultiSigWalletWithTimeLockExceptRemoveAuthorizedAddress.sol
diff --git a/packages/contracts/src/contracts/previous/Ownable/IOwnable_v1.sol b/packages/contracts/src/1.0.0/Ownable/IOwnable_v1.sol
index 7e22d544d..7e22d544d 100644
--- a/packages/contracts/src/contracts/previous/Ownable/IOwnable_v1.sol
+++ b/packages/contracts/src/1.0.0/Ownable/IOwnable_v1.sol
diff --git a/packages/contracts/src/contracts/previous/Ownable/Ownable_v1.sol b/packages/contracts/src/1.0.0/Ownable/Ownable_v1.sol
index c87438fa4..c87438fa4 100644
--- a/packages/contracts/src/contracts/previous/Ownable/Ownable_v1.sol
+++ b/packages/contracts/src/1.0.0/Ownable/Ownable_v1.sol
diff --git a/packages/contracts/src/contracts/previous/SafeMath/SafeMath_v1.sol b/packages/contracts/src/1.0.0/SafeMath/SafeMath_v1.sol
index 341d611ec..341d611ec 100644
--- a/packages/contracts/src/contracts/previous/SafeMath/SafeMath_v1.sol
+++ b/packages/contracts/src/1.0.0/SafeMath/SafeMath_v1.sol
diff --git a/packages/contracts/src/contracts/previous/Token/Token_v1.sol b/packages/contracts/src/1.0.0/Token/Token_v1.sol
index de619fb7e..de619fb7e 100644
--- a/packages/contracts/src/contracts/previous/Token/Token_v1.sol
+++ b/packages/contracts/src/1.0.0/Token/Token_v1.sol
diff --git a/packages/contracts/src/contracts/previous/TokenRegistry/ITokenRegistery.sol b/packages/contracts/src/1.0.0/TokenRegistry/ITokenRegistery.sol
index b8bdaf3b9..b8bdaf3b9 100644
--- a/packages/contracts/src/contracts/previous/TokenRegistry/ITokenRegistery.sol
+++ b/packages/contracts/src/1.0.0/TokenRegistry/ITokenRegistery.sol
diff --git a/packages/contracts/src/contracts/previous/TokenRegistry/TokenRegistry.sol b/packages/contracts/src/1.0.0/TokenRegistry/TokenRegistry.sol
index 7417a10a3..7417a10a3 100644
--- a/packages/contracts/src/contracts/previous/TokenRegistry/TokenRegistry.sol
+++ b/packages/contracts/src/1.0.0/TokenRegistry/TokenRegistry.sol
diff --git a/packages/contracts/src/contracts/previous/TokenTransferProxy/TokenTransferProxy_v1.sol b/packages/contracts/src/1.0.0/TokenTransferProxy/TokenTransferProxy_v1.sol
index e3659d8ba..e3659d8ba 100644
--- a/packages/contracts/src/contracts/previous/TokenTransferProxy/TokenTransferProxy_v1.sol
+++ b/packages/contracts/src/1.0.0/TokenTransferProxy/TokenTransferProxy_v1.sol
diff --git a/packages/contracts/src/contracts/previous/UnlimitedAllowanceToken/UnlimitedAllowanceToken_v1.sol b/packages/contracts/src/1.0.0/UnlimitedAllowanceToken/UnlimitedAllowanceToken_v1.sol
index 46379c43d..46379c43d 100644
--- a/packages/contracts/src/contracts/previous/UnlimitedAllowanceToken/UnlimitedAllowanceToken_v1.sol
+++ b/packages/contracts/src/1.0.0/UnlimitedAllowanceToken/UnlimitedAllowanceToken_v1.sol
diff --git a/packages/contracts/src/contracts/current/multisig/MultiSigWallet.sol b/packages/contracts/src/2.0.0/multisig/MultiSigWallet.sol
index 79fd92029..79fd92029 100644
--- a/packages/contracts/src/contracts/current/multisig/MultiSigWallet.sol
+++ b/packages/contracts/src/2.0.0/multisig/MultiSigWallet.sol
diff --git a/packages/contracts/src/contracts/current/multisig/MultiSigWalletWithTimeLock.sol b/packages/contracts/src/2.0.0/multisig/MultiSigWalletWithTimeLock.sol
index 9766c2158..9766c2158 100644
--- a/packages/contracts/src/contracts/current/multisig/MultiSigWalletWithTimeLock.sol
+++ b/packages/contracts/src/2.0.0/multisig/MultiSigWalletWithTimeLock.sol
diff --git a/packages/contracts/src/2.0.0/protocol/AssetProxy/ERC20Proxy.sol b/packages/contracts/src/2.0.0/protocol/AssetProxy/ERC20Proxy.sol
new file mode 100644
index 000000000..aed62f54f
--- /dev/null
+++ b/packages/contracts/src/2.0.0/protocol/AssetProxy/ERC20Proxy.sol
@@ -0,0 +1,132 @@
+/*
+
+  Copyright 2018 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity ^0.4.24;
+pragma experimental ABIEncoderV2;
+
+import "../../utils/LibBytes/LibBytes.sol";
+import "./MixinAuthorizable.sol";
+
+contract ERC20Proxy is
+    MixinAuthorizable
+{
+    // Id of this proxy.
+    bytes4 constant PROXY_ID = bytes4(keccak256("ERC20Token(address)"));
+    
+    function () 
+        external
+    {
+        assembly {
+            // The first 4 bytes of calldata holds the function selector
+            let selector := and(calldataload(0), 0xffffffff00000000000000000000000000000000000000000000000000000000)
+
+            // `transferFrom` will be called with the following parameters:
+            // assetData Encoded byte array.
+            // from Address to transfer asset from.
+            // to Address to transfer asset to.
+            // amount Amount of asset to transfer.
+            // bytes4(keccak256("transferFrom(bytes,address,address,uint256)")) = 0xa85e59e4
+            if eq(selector, 0xa85e59e400000000000000000000000000000000000000000000000000000000) {
+
+                // To lookup a value in a mapping, we load from the storage location keccak256(k, p),
+                // where k is the key left padded to 32 bytes and p is the storage slot
+                let start := mload(64)
+                mstore(start, and(caller, 0xffffffffffffffffffffffffffffffffffffffff))
+                mstore(add(start, 32), authorized_slot)
+
+                // Revert if authorized[msg.sender] == false
+                if iszero(sload(keccak256(start, 64))) {
+                    // Revert with `Error("SENDER_NOT_AUTHORIZED")`
+                    mstore(0, 0x08c379a000000000000000000000000000000000000000000000000000000000)
+                    mstore(32, 0x0000002000000000000000000000000000000000000000000000000000000000)
+                    mstore(64, 0x0000001553454e4445525f4e4f545f415554484f52495a454400000000000000)
+                    mstore(96, 0)
+                    revert(0, 100)
+                }
+                
+                /////// Token contract address ///////
+                // The token address is found as follows:
+                // * It is stored at offset 4 in `assetData` contents.
+                // * This is stored at offset 32 from `assetData`.
+                // * The offset to `assetData` from Params is stored at offset
+                //   4 in calldata.
+                // * The offset of Params in calldata is 4.
+                // So we read location 4 and add 32 + 4 + 4 to it.
+                let token := calldataload(add(calldataload(4), 40))
+                
+                /////// Setup Header Area ///////
+                // This area holds the 4-byte `transferFrom` selector.
+                // Any trailing data in transferFromSelector will be
+                // overwritten in the next `mstore` call.
+                mstore(0, 0x23b872dd00000000000000000000000000000000000000000000000000000000)
+                
+                /////// Setup Params Area ///////
+                // We copy the fields `from`, `to` and `amount` in bulk
+                // from our own calldata to the new calldata.
+                calldatacopy(4, 36, 96)
+
+                /////// Call `token.transferFrom` using the calldata ///////
+                let success := call(
+                    gas,            // forward all gas
+                    token,          // call address of token contract
+                    0,              // don't send any ETH
+                    0,              // pointer to start of input
+                    100,            // length of input
+                    0,              // write output over input
+                    32              // output size should be 32 bytes
+                )
+
+                /////// Check return data. ///////
+                // If there is no return data, we assume the token incorrectly
+                // does not return a bool. In this case we expect it to revert
+                // on failure, which was handled above.
+                // If the token does return data, we require that it is a single
+                // nonzero 32 bytes value.
+                // So the transfer succeeded if the call succeeded and either
+                // returned nothing, or returned a non-zero 32 byte value. 
+                success := and(success, or(
+                    iszero(returndatasize),
+                    and(
+                        eq(returndatasize, 32),
+                        gt(mload(0), 0)
+                    )
+                ))
+                if success {
+                    return(0, 0)
+                }
+                
+                // Revert with `Error("TRANSFER_FAILED")`
+                mstore(0, 0x08c379a000000000000000000000000000000000000000000000000000000000)
+                mstore(32, 0x0000002000000000000000000000000000000000000000000000000000000000)
+                mstore(64, 0x0000000f5452414e534645525f4641494c454400000000000000000000000000)
+                mstore(96, 0)
+                revert(0, 100)
+            }
+        }
+    }
+
+    /// @dev Gets the proxy id associated with the proxy address.
+    /// @return Proxy id.
+    function getProxyId()
+        external
+        pure
+        returns (bytes4)
+    {
+        return PROXY_ID;
+    }
+}
diff --git a/packages/contracts/src/2.0.0/protocol/AssetProxy/ERC721Proxy.sol b/packages/contracts/src/2.0.0/protocol/AssetProxy/ERC721Proxy.sol
new file mode 100644
index 000000000..b73dc36cc
--- /dev/null
+++ b/packages/contracts/src/2.0.0/protocol/AssetProxy/ERC721Proxy.sol
@@ -0,0 +1,218 @@
+/*
+
+  Copyright 2018 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity ^0.4.24;
+pragma experimental ABIEncoderV2;
+
+import "../../utils/LibBytes/LibBytes.sol";
+import "./MixinAuthorizable.sol";
+
+contract ERC721Proxy is
+    MixinAuthorizable
+{
+    // Id of this proxy.
+    bytes4 constant PROXY_ID = bytes4(keccak256("ERC721Token(address,uint256,bytes)"));
+
+    function () 
+        external
+    {
+        assembly {
+            // The first 4 bytes of calldata holds the function selector
+            let selector := and(calldataload(0), 0xffffffff00000000000000000000000000000000000000000000000000000000)
+
+            // `transferFrom` will be called with the following parameters:
+            // assetData Encoded byte array.
+            // from Address to transfer asset from.
+            // to Address to transfer asset to.
+            // amount Amount of asset to transfer.
+            // bytes4(keccak256("transferFrom(bytes,address,address,uint256)")) = 0xa85e59e4
+            if eq(selector, 0xa85e59e400000000000000000000000000000000000000000000000000000000) {
+
+                // To lookup a value in a mapping, we load from the storage location keccak256(k, p),
+                // where k is the key left padded to 32 bytes and p is the storage slot
+                let start := mload(64)
+                mstore(start, and(caller, 0xffffffffffffffffffffffffffffffffffffffff))
+                mstore(add(start, 32), authorized_slot)
+
+                // Revert if authorized[msg.sender] == false
+                if iszero(sload(keccak256(start, 64))) {
+                    // Revert with `Error("SENDER_NOT_AUTHORIZED")`
+                    mstore(0, 0x08c379a000000000000000000000000000000000000000000000000000000000)
+                    mstore(32, 0x0000002000000000000000000000000000000000000000000000000000000000)
+                    mstore(64, 0x0000001553454e4445525f4e4f545f415554484f52495a454400000000000000)
+                    mstore(96, 0)
+                    revert(0, 100)
+                }
+
+                // `transferFrom`.
+                // The function is marked `external`, so no abi decodeding is done for
+                // us. Instead, we expect the `calldata` memory to contain the
+                // following:
+                //
+                // | Area     | Offset | Length  | Contents                            |
+                // |----------|--------|---------|-------------------------------------|
+                // | Header   | 0      | 4       | function selector                   |
+                // | Params   |        | 4 * 32  | function parameters:                |
+                // |          | 4      |         |   1. offset to assetData (*)        |
+                // |          | 36     |         |   2. from                           |
+                // |          | 68     |         |   3. to                             |
+                // |          | 100    |         |   4. amount                         |
+                // | Data     |        |         | assetData:                          |
+                // |          | 132    | 32      | assetData Length                    |
+                // |          | 164    | **      | assetData Contents                  |
+                //
+                // (*): offset is computed from start of function parameters, so offset
+                //      by an additional 4 bytes in the calldata.
+                //
+                // WARNING: The ABIv2 specification allows additional padding between
+                //          the Params and Data section. This will result in a larger
+                //          offset to assetData.
+                
+                // Asset data itself is encoded as follows:
+                //
+                // | Area     | Offset | Length  | Contents                            |
+                // |----------|--------|---------|-------------------------------------|
+                // | Header   | 0      | 4       | function selector                   |
+                // | Params   |        | 3 * 32  | function parameters:                |
+                // |          | 4      | 12 + 20 |   1. token address                  |
+                // |          | 36     |         |   2. tokenId                        |
+                // |          | 68     |         |   3. offset to receiverData (*)     |
+                // | Data     |        |         | receiverData:                       |
+                // |          | 100    | 32      | receiverData Length                 |
+                // |          | 132    | **      | receiverData Contents               |
+                
+                // We construct calldata for the `token.safeTransferFrom` ABI.
+                // The layout of this calldata is in the table below.
+                // 
+                // | Area     | Offset | Length  | Contents                            |
+                // |----------|--------|---------|-------------------------------------|
+                // | Header   | 0      | 4       | function selector                   |
+                // | Params   |        | 4 * 32  | function parameters:                |
+                // |          | 4      |         |   1. from                           |
+                // |          | 36     |         |   2. to                             |
+                // |          | 68     |         |   3. tokenId                        |
+                // |          | 100    |         |   4. offset to receiverData (*)     |
+                // | Data     |        |         | receiverData:                       |
+                // |          | 132    | 32      | receiverData Length                 |
+                // |          | 164    | **      | receiverData Contents               |
+
+                // There exists only 1 of each token.
+                // require(amount == 1, "INVALID_AMOUNT")
+                if sub(calldataload(100), 1) {
+                    // Revert with `Error("INVALID_AMOUNT")`
+                    mstore(0, 0x08c379a000000000000000000000000000000000000000000000000000000000)
+                    mstore(32, 0x0000002000000000000000000000000000000000000000000000000000000000)
+                    mstore(64, 0x0000000e494e56414c49445f414d4f554e540000000000000000000000000000)
+                    mstore(96, 0)
+                    revert(0, 100)
+                }
+                
+                // Require assetData to be at least 132 bytes
+                let offset := calldataload(4)
+                if lt(calldataload(add(offset, 4)), 132) {
+                    // Revert with `Error("LENGTH_GREATER_THAN_131_REQUIRED")`
+                    mstore(0, 0x08c379a000000000000000000000000000000000000000000000000000000000)
+                    mstore(32, 0x0000002000000000000000000000000000000000000000000000000000000000)
+                    mstore(64, 0x000000204c454e4754485f475245415445525f5448414e5f3133315f52455155)
+                    mstore(96, 0x4952454400000000000000000000000000000000000000000000000000000000)
+                    revert(0, 100)
+                }
+                
+                /////// Setup State ///////
+                // `cdStart` is the start of the calldata for
+                // `token.safeTransferFrom` (equal to free memory ptr).
+                let cdStart := mload(64)
+                // `dataAreaLength` is the total number of words
+                // needed to store `receiverData`
+                // As-per the ABI spec, this value is padded up to
+                // the nearest multiple of 32,
+                // and includes 32-bytes for length.
+                // It's calculated as folows:
+                //      - Unpadded length in bytes = `mload(receiverData) + 32`
+                //      - Add 31 to convert rounding down to rounding up.
+                //        Combined with the previous and this is `63`.
+                //      - Round down to nearest multiple of 32 by clearing
+                //        bits 0x1F. This is done with `and` and a mask.
+
+                /////// Setup Header Area ///////
+                // This area holds the 4-byte `transferFromSelector`.
+                // Any trailing data in transferFromSelector will be
+                // overwritten in the next `mstore` call.
+                mstore(cdStart, 0xb88d4fde00000000000000000000000000000000000000000000000000000000)
+                
+                /////// Setup Params Area ///////
+                // Each parameter is padded to 32-bytes.
+                // The entire Params Area is 128 bytes.
+                // Notes:
+                //   1. A 20-byte mask is applied to addresses
+                //      to zero-out the unused bytes.
+                //   2. The offset to `receiverData` is the length
+                //      of the Params Area (128 bytes).
+                
+                let length := calldataload(add(offset, 136))
+                let token := calldataload(add(offset, 40))
+                
+                // Round length up to multiple of 32
+                length := and(add(length, 31), 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFE0)
+                
+                // Copy `from` and `to`
+                calldatacopy(add(cdStart, 4), 36, 64)
+                
+                // TokenId
+                mstore(add(cdStart, 68), calldataload(add(offset, 72)))
+                
+                // Offset to receiverData
+                mstore(add(cdStart, 100), 128)
+                
+                // receiverData (including length)
+                calldatacopy(add(cdStart, 132), add(offset, 136), add(length, 32))
+                
+                /////// Call `token.safeTransferFrom` using the calldata ///////
+                let success := call(
+                    gas,                    // forward all gas
+                    token,                  // call address of token contract
+                    0,                      // don't send any ETH
+                    cdStart,                // pointer to start of input
+                    add(length, 164),       // length of input
+                    0,                      // write output to null
+                    0                       // output size is 0 bytes
+                )
+                if success {
+                    return(0, 0)
+                }
+                
+                // Revert with `Error("TRANSFER_FAILED")`
+                mstore(0, 0x08c379a000000000000000000000000000000000000000000000000000000000)
+                mstore(32, 0x0000002000000000000000000000000000000000000000000000000000000000)
+                mstore(64, 0x0000000f5452414e534645525f4641494c454400000000000000000000000000)
+                mstore(96, 0)
+                revert(0, 100)
+            }
+        }
+    }
+
+    /// @dev Gets the proxy id associated with the proxy address.
+    /// @return Proxy id.
+    function getProxyId()
+        external
+        pure
+        returns (bytes4)
+    {
+        return PROXY_ID;
+    }
+}
diff --git a/packages/contracts/src/contracts/current/protocol/AssetProxy/MixinAuthorizable.sol b/packages/contracts/src/2.0.0/protocol/AssetProxy/MixinAuthorizable.sol
index 37c12f861..3b9584a44 100644
--- a/packages/contracts/src/contracts/current/protocol/AssetProxy/MixinAuthorizable.sol
+++ b/packages/contracts/src/2.0.0/protocol/AssetProxy/MixinAuthorizable.sol
@@ -19,12 +19,10 @@
 pragma solidity ^0.4.24;
 pragma experimental ABIEncoderV2;
 
-import "./libs/LibAssetProxyErrors.sol";
 import "../../utils/Ownable/Ownable.sol";
 import "./mixins/MAuthorizable.sol";
 
 contract MixinAuthorizable is
-    LibAssetProxyErrors,
     Ownable,
     MAuthorizable
 {
@@ -33,7 +31,7 @@ contract MixinAuthorizable is
     modifier onlyAuthorized {
         require(
             authorized[msg.sender],
-            SENDER_NOT_AUTHORIZED
+            "SENDER_NOT_AUTHORIZED"
         );
         _;
     }
@@ -49,7 +47,7 @@ contract MixinAuthorizable is
     {
         require(
             !authorized[target],
-            TARGET_ALREADY_AUTHORIZED
+            "TARGET_ALREADY_AUTHORIZED"
         );
 
         authorized[target] = true;
@@ -65,7 +63,7 @@ contract MixinAuthorizable is
     {
         require(
             authorized[target],
-            TARGET_NOT_AUTHORIZED
+            "TARGET_NOT_AUTHORIZED"
         );
 
         delete authorized[target];
@@ -91,15 +89,15 @@ contract MixinAuthorizable is
     {
         require(
             authorized[target],
-            TARGET_NOT_AUTHORIZED
+            "TARGET_NOT_AUTHORIZED"
         );
         require(
             index < authorities.length,
-            INDEX_OUT_OF_BOUNDS
+            "INDEX_OUT_OF_BOUNDS"
         );
         require(
             authorities[index] == target,
-            AUTHORIZED_ADDRESS_MISMATCH
+            "AUTHORIZED_ADDRESS_MISMATCH"
         );
 
         delete authorized[target];
diff --git a/packages/contracts/src/contracts/current/protocol/AssetProxy/libs/LibTransferErrors.sol b/packages/contracts/src/2.0.0/protocol/AssetProxy/interfaces/IAssetData.sol
index ba784ab22..7ebd6acf0 100644
--- a/packages/contracts/src/contracts/current/protocol/AssetProxy/libs/LibTransferErrors.sol
+++ b/packages/contracts/src/2.0.0/protocol/AssetProxy/interfaces/IAssetData.sol
@@ -16,10 +16,23 @@
 
 */
 
-pragma solidity ^0.4.24;
+pragma solidity ^0.4.23;
 
-contract LibTransferErrors {
-    /// Transfer errors ///
-    string constant INVALID_AMOUNT = "INVALID_AMOUNT";                            // Transfer amount must equal 1.
-    string constant TRANSFER_FAILED = "TRANSFER_FAILED";                          // Transfer failed.
+// @dev Interface of the asset proxy's assetData.
+// The asset proxies take an ABI encoded `bytes assetData` as argument.
+// This argument is ABI encoded as one of the methods of this interface.
+interface IAssetData {
+    
+    function ERC20Token(address tokenContract)
+        external
+        pure;
+    
+    function ERC721Token(
+        address tokenContract,
+        uint256 tokenId,
+        bytes receiverData
+    )
+        external
+        pure;
+    
 }
diff --git a/packages/contracts/src/contracts/current/protocol/AssetProxy/interfaces/IAssetProxy.sol b/packages/contracts/src/2.0.0/protocol/AssetProxy/interfaces/IAssetProxy.sol
index 22f43b12f..eacd5a412 100644
--- a/packages/contracts/src/contracts/current/protocol/AssetProxy/interfaces/IAssetProxy.sol
+++ b/packages/contracts/src/2.0.0/protocol/AssetProxy/interfaces/IAssetProxy.sol
@@ -38,24 +38,10 @@ contract IAssetProxy is
     )
         external;
     
-    /// @dev Makes multiple transfers of assets. Either succeeds or throws.
-    /// @param assetData Array of byte arrays encoded for the respective asset proxy.
-    /// @param from Array of addresses to transfer assets from.
-    /// @param to Array of addresses to transfer assets to.
-    /// @param amounts Array of amounts of assets to transfer.
-    function batchTransferFrom(
-        bytes[] memory assetData,
-        address[] memory from,
-        address[] memory to,
-        uint256[] memory amounts
-    )
-        public;
-
     /// @dev Gets the proxy id associated with the proxy address.
     /// @return Proxy id.
     function getProxyId()
         external
-        view
-        returns (uint8);
+        pure
+        returns (bytes4);
 }
-
diff --git a/packages/contracts/src/contracts/current/protocol/AssetProxy/interfaces/IAuthorizable.sol b/packages/contracts/src/2.0.0/protocol/AssetProxy/interfaces/IAuthorizable.sol
index cedd1744c..cedd1744c 100644
--- a/packages/contracts/src/contracts/current/protocol/AssetProxy/interfaces/IAuthorizable.sol
+++ b/packages/contracts/src/2.0.0/protocol/AssetProxy/interfaces/IAuthorizable.sol
diff --git a/packages/contracts/src/contracts/current/protocol/AssetProxy/libs/LibAssetProxyErrors.sol b/packages/contracts/src/2.0.0/protocol/AssetProxy/libs/LibAssetProxyErrors.sol
index dca4f400f..338cb12e2 100644
--- a/packages/contracts/src/contracts/current/protocol/AssetProxy/libs/LibAssetProxyErrors.sol
+++ b/packages/contracts/src/2.0.0/protocol/AssetProxy/libs/LibAssetProxyErrors.sol
@@ -18,11 +18,19 @@
 
 pragma solidity ^0.4.24;
 
+/// @dev This contract documents the revert reasons used in the AssetProxy contracts.
+/// This contract is intended to serve as a reference, but is not actually used for efficiency reasons.
 contract LibAssetProxyErrors {
+
     /// Authorizable errors ///
-    string constant SENDER_NOT_AUTHORIZED = "SENDER_NOT_AUTHORIZED";              // Sender not authorized to call this method.
-    string constant TARGET_NOT_AUTHORIZED = "TARGET_NOT_AUTHORIZED";              // Target address not authorized to call this method.
-    string constant TARGET_ALREADY_AUTHORIZED = "TARGET_ALREADY_AUTHORIZED";      // Target address must not already be authorized.
-    string constant INDEX_OUT_OF_BOUNDS = "INDEX_OUT_OF_BOUNDS";                  // Specified array index is out of bounds.
-    string constant AUTHORIZED_ADDRESS_MISMATCH = "AUTHORIZED_ADDRESS_MISMATCH";  // Address at index does not match given target address.
+    string constant SENDER_NOT_AUTHORIZED = "SENDER_NOT_AUTHORIZED";                        // Sender not authorized to call this method.
+    string constant TARGET_NOT_AUTHORIZED = "TARGET_NOT_AUTHORIZED";                        // Target address not authorized to call this method.
+    string constant TARGET_ALREADY_AUTHORIZED = "TARGET_ALREADY_AUTHORIZED";                // Target address must not already be authorized.
+    string constant INDEX_OUT_OF_BOUNDS = "INDEX_OUT_OF_BOUNDS";                            // Specified array index is out of bounds.
+    string constant AUTHORIZED_ADDRESS_MISMATCH = "AUTHORIZED_ADDRESS_MISMATCH";            // Address at index does not match given target address.
+
+    /// Transfer errors ///
+    string constant INVALID_AMOUNT = "INVALID_AMOUNT";                                      // Transfer amount must equal 1.
+    string constant TRANSFER_FAILED = "TRANSFER_FAILED";                                    // Transfer failed.
+    string constant LENGTH_GREATER_THAN_131_REQUIRED = "LENGTH_GREATER_THAN_131_REQUIRED";  // Byte array must have a length greater than 0.
 }
diff --git a/packages/contracts/src/contracts/current/protocol/AssetProxy/mixins/MAuthorizable.sol b/packages/contracts/src/2.0.0/protocol/AssetProxy/mixins/MAuthorizable.sol
index 6f35bd7ec..6f35bd7ec 100644
--- a/packages/contracts/src/contracts/current/protocol/AssetProxy/mixins/MAuthorizable.sol
+++ b/packages/contracts/src/2.0.0/protocol/AssetProxy/mixins/MAuthorizable.sol
diff --git a/packages/contracts/src/contracts/current/protocol/AssetProxyOwner/AssetProxyOwner.sol b/packages/contracts/src/2.0.0/protocol/AssetProxyOwner/AssetProxyOwner.sol
index eb58b3374..eb58b3374 100644
--- a/packages/contracts/src/contracts/current/protocol/AssetProxyOwner/AssetProxyOwner.sol
+++ b/packages/contracts/src/2.0.0/protocol/AssetProxyOwner/AssetProxyOwner.sol
diff --git a/packages/contracts/src/contracts/current/protocol/Exchange/Exchange.sol b/packages/contracts/src/2.0.0/protocol/Exchange/Exchange.sol
index d36e9633e..d36e9633e 100644
--- a/packages/contracts/src/contracts/current/protocol/Exchange/Exchange.sol
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/Exchange.sol
diff --git a/packages/contracts/src/2.0.0/protocol/Exchange/MixinAssetProxyDispatcher.sol b/packages/contracts/src/2.0.0/protocol/Exchange/MixinAssetProxyDispatcher.sol
new file mode 100644
index 000000000..9e9d88ce7
--- /dev/null
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/MixinAssetProxyDispatcher.sol
@@ -0,0 +1,175 @@
+/*
+
+  Copyright 2018 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity ^0.4.24;
+
+import "../../utils/Ownable/Ownable.sol";
+import "../../utils/LibBytes/LibBytes.sol";
+import "./mixins/MAssetProxyDispatcher.sol";
+import "../AssetProxy/interfaces/IAssetProxy.sol";
+
+contract MixinAssetProxyDispatcher is
+    Ownable,
+    MAssetProxyDispatcher
+{
+    using LibBytes for bytes;
+    
+    // Mapping from Asset Proxy Id's to their respective Asset Proxy
+    mapping (bytes4 => IAssetProxy) public assetProxies;
+
+    /// @dev Registers an asset proxy to its asset proxy id.
+    ///      Once an asset proxy is registered, it cannot be unregistered.
+    /// @param assetProxy Address of new asset proxy to register.
+    function registerAssetProxy(address assetProxy)
+        external
+        onlyOwner
+    {
+        IAssetProxy assetProxyContract = IAssetProxy(assetProxy);
+
+        // Ensure that no asset proxy exists with current id.
+        bytes4 assetProxyId = assetProxyContract.getProxyId();
+        address currentAssetProxy = assetProxies[assetProxyId];
+        require(
+            currentAssetProxy == address(0),
+            "ASSET_PROXY_ALREADY_EXISTS"
+        );
+
+        // Add asset proxy and log registration.
+        assetProxies[assetProxyId] = assetProxyContract;
+        emit AssetProxyRegistered(
+            assetProxyId,
+            assetProxy
+        );
+    }
+
+    /// @dev Gets an asset proxy.
+    /// @param assetProxyId Id of the asset proxy.
+    /// @return The asset proxy registered to assetProxyId. Returns 0x0 if no proxy is registered.
+    function getAssetProxy(bytes4 assetProxyId)
+        external
+        view
+        returns (address)
+    {
+        return assetProxies[assetProxyId];
+    }
+
+    /// @dev Forwards arguments to assetProxy and calls `transferFrom`. Either succeeds or throws.
+    /// @param assetData Byte array encoded for the asset.
+    /// @param from Address to transfer token from.
+    /// @param to Address to transfer token to.
+    /// @param amount Amount of token to transfer.
+    function dispatchTransferFrom(
+        bytes memory assetData,
+        address from,
+        address to,
+        uint256 amount
+    )
+        internal
+    {
+        // Do nothing if no amount should be transferred.
+        if (amount > 0) {
+            // Ensure assetData length is valid
+            require(
+                assetData.length > 3,
+                "LENGTH_GREATER_THAN_3_REQUIRED"
+            );
+            
+            // Lookup assetProxy
+            bytes4 assetProxyId;
+            assembly {
+                assetProxyId := and(mload(
+                    add(assetData, 32)),
+                    0xFFFFFFFF00000000000000000000000000000000000000000000000000000000
+                )
+            }
+            address assetProxy = assetProxies[assetProxyId];
+
+            // Ensure that assetProxy exists
+            require(
+                assetProxy != address(0),
+                "ASSET_PROXY_DOES_NOT_EXIST"
+            );
+            
+            // We construct calldata for the `assetProxy.transferFrom` ABI.
+            // The layout of this calldata is in the table below.
+            // 
+            // | Area     | Offset | Length  | Contents                                    |
+            // | -------- |--------|---------|-------------------------------------------- |
+            // | Header   | 0      | 4       | function selector                           |
+            // | Params   |        | 4 * 32  | function parameters:                        |
+            // |          | 4      |         |   1. offset to assetData (*)                |
+            // |          | 36     |         |   2. from                                   |
+            // |          | 68     |         |   3. to                                     |
+            // |          | 100    |         |   4. amount                                 |
+            // | Data     |        |         | assetData:                                  |
+            // |          | 132    | 32      | assetData Length                            |
+            // |          | 164    | **      | assetData Contents                          |
+
+            assembly {
+                /////// Setup State ///////
+                // `cdStart` is the start of the calldata for `assetProxy.transferFrom` (equal to free memory ptr).
+                let cdStart := mload(64)
+                // `dataAreaLength` is the total number of words needed to store `assetData`
+                //  As-per the ABI spec, this value is padded up to the nearest multiple of 32,
+                //  and includes 32-bytes for length.
+                let dataAreaLength := and(add(mload(assetData), 63), 0xFFFFFFFFFFFE0)
+                // `cdEnd` is the end of the calldata for `assetProxy.transferFrom`.
+                let cdEnd := add(cdStart, add(132, dataAreaLength))
+
+                
+                /////// Setup Header Area ///////
+                // This area holds the 4-byte `transferFromSelector`.
+                // bytes4(keccak256("transferFrom(bytes,address,address,uint256)")) = 0xa85e59e4
+                mstore(cdStart, 0xa85e59e400000000000000000000000000000000000000000000000000000000)
+                
+                /////// Setup Params Area ///////
+                // Each parameter is padded to 32-bytes. The entire Params Area is 128 bytes.
+                // Notes:
+                //   1. The offset to `assetData` is the length of the Params Area (128 bytes).
+                //   2. A 20-byte mask is applied to addresses to zero-out the unused bytes.
+                mstore(add(cdStart, 4), 128)
+                mstore(add(cdStart, 36), and(from, 0xffffffffffffffffffffffffffffffffffffffff))
+                mstore(add(cdStart, 68), and(to, 0xffffffffffffffffffffffffffffffffffffffff))
+                mstore(add(cdStart, 100), amount)
+                
+                /////// Setup Data Area ///////
+                // This area holds `assetData`.
+                let dataArea := add(cdStart, 132)
+                for {} lt(dataArea, cdEnd) {} {
+                    mstore(dataArea, mload(assetData))
+                    dataArea := add(dataArea, 32)
+                    assetData := add(assetData, 32)
+                }
+
+                /////// Call `assetProxy.transferFrom` using the constructed calldata ///////
+                let success := call(
+                    gas,                    // forward all gas
+                    assetProxy,             // call address of asset proxy
+                    0,                      // don't send any ETH
+                    cdStart,                // pointer to start of input
+                    sub(cdEnd, cdStart),    // length of input  
+                    cdStart,                // write output over input
+                    512                     // reserve 512 bytes for output
+                )
+                if iszero(success) {
+                    revert(cdStart, returndatasize())
+                }
+            }
+        }
+    }
+}
diff --git a/packages/contracts/src/contracts/current/protocol/Exchange/MixinExchangeCore.sol b/packages/contracts/src/2.0.0/protocol/Exchange/MixinExchangeCore.sol
index b207b3e57..c0ed023ac 100644
--- a/packages/contracts/src/contracts/current/protocol/Exchange/MixinExchangeCore.sol
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/MixinExchangeCore.sol
@@ -20,11 +20,9 @@ pragma solidity ^0.4.24;
 pragma experimental ABIEncoderV2;
 
 import "./libs/LibConstants.sol";
-import "../../utils/LibBytes/LibBytes.sol";
 import "./libs/LibFillResults.sol";
 import "./libs/LibOrder.sol";
 import "./libs/LibMath.sol";
-import "./libs/LibExchangeErrors.sol";
 import "./mixins/MExchangeCore.sol";
 import "./mixins/MSignatureValidator.sol";
 import "./mixins/MTransactions.sol";
@@ -35,14 +33,11 @@ contract MixinExchangeCore is
     LibMath,
     LibOrder,
     LibFillResults,
-    LibExchangeErrors,
     MAssetProxyDispatcher,
     MExchangeCore,
     MSignatureValidator,
     MTransactions
 {
-    using LibBytes for bytes;
-    
     // Mapping of orderHash => amount of takerAsset already bought by maker
     mapping (bytes32 => uint256) public filled;
 
@@ -73,7 +68,7 @@ contract MixinExchangeCore is
         // Ensure orderEpoch is monotonically increasing
         require(
             newOrderEpoch > oldOrderEpoch, 
-            INVALID_NEW_ORDER_EPOCH
+            "INVALID_NEW_ORDER_EPOCH"
         );
 
         // Update orderEpoch
@@ -285,20 +280,20 @@ contract MixinExchangeCore is
         // An order can only be filled if its status is FILLABLE.
         require(
             orderInfo.orderStatus == uint8(OrderStatus.FILLABLE),
-            ORDER_UNFILLABLE
+            "ORDER_UNFILLABLE"
         );
 
         // Revert if fill amount is invalid
         require(
             takerAssetFillAmount != 0,
-            INVALID_TAKER_AMOUNT
+            "INVALID_TAKER_AMOUNT"
         );
 
         // Validate sender is allowed to fill this order
         if (order.senderAddress != address(0)) {
             require(
                 order.senderAddress == msg.sender,
-                INVALID_SENDER
+                "INVALID_SENDER"
             );
         }
 
@@ -306,7 +301,7 @@ contract MixinExchangeCore is
         if (order.takerAddress != address(0)) {
             require(
                 order.takerAddress == takerAddress,
-                INVALID_TAKER
+                "INVALID_TAKER"
             );
         }
 
@@ -318,7 +313,7 @@ contract MixinExchangeCore is
                     order.makerAddress,
                     signature
                 ),
-                INVALID_ORDER_SIGNATURE
+                "INVALID_ORDER_SIGNATURE"
             );
         }
 
@@ -329,7 +324,7 @@ contract MixinExchangeCore is
                 order.takerAssetAmount,
                 order.makerAssetAmount
             ),
-            ROUNDING_ERROR
+            "ROUNDING_ERROR"
         );
     }
 
@@ -347,14 +342,14 @@ contract MixinExchangeCore is
         // An order can only be cancelled if its status is FILLABLE.
         require(
             orderInfo.orderStatus == uint8(OrderStatus.FILLABLE),
-            ORDER_UNFILLABLE
+            "ORDER_UNFILLABLE"
         );
 
         // Validate sender is allowed to cancel this order
         if (order.senderAddress != address(0)) {
             require(
                 order.senderAddress == msg.sender,
-                INVALID_SENDER
+                "INVALID_SENDER"
             );
         }
 
@@ -362,7 +357,7 @@ contract MixinExchangeCore is
         address makerAddress = getCurrentContextAddress();
         require(
             order.makerAddress == makerAddress,
-            INVALID_MAKER
+            "INVALID_MAKER"
         );
     }
 
@@ -412,33 +407,27 @@ contract MixinExchangeCore is
     )
         private
     {
-        uint8 makerAssetProxyId = uint8(order.makerAssetData.popLastByte());
-        uint8 takerAssetProxyId = uint8(order.takerAssetData.popLastByte());
         bytes memory zrxAssetData = ZRX_ASSET_DATA;
         dispatchTransferFrom(
             order.makerAssetData,
-            makerAssetProxyId,
             order.makerAddress,
             takerAddress,
             fillResults.makerAssetFilledAmount
         );
         dispatchTransferFrom(
             order.takerAssetData,
-            takerAssetProxyId,
             takerAddress,
             order.makerAddress,
             fillResults.takerAssetFilledAmount
         );
         dispatchTransferFrom(
             zrxAssetData,
-            ZRX_PROXY_ID,
             order.makerAddress,
             order.feeRecipientAddress,
             fillResults.makerFeePaid
         );
         dispatchTransferFrom(
             zrxAssetData,
-            ZRX_PROXY_ID,
             takerAddress,
             order.feeRecipientAddress,
             fillResults.takerFeePaid
diff --git a/packages/contracts/src/contracts/current/protocol/Exchange/MixinMatchOrders.sol b/packages/contracts/src/2.0.0/protocol/Exchange/MixinMatchOrders.sol
index e36fcc2c5..1a43eec79 100644
--- a/packages/contracts/src/contracts/current/protocol/Exchange/MixinMatchOrders.sol
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/MixinMatchOrders.sol
@@ -15,11 +15,9 @@ pragma solidity ^0.4.24;
 pragma experimental ABIEncoderV2;
 
 import "./libs/LibConstants.sol";
-import "../../utils/LibBytes/LibBytes.sol";
 import "./libs/LibMath.sol";
 import "./libs/LibOrder.sol";
 import "./libs/LibFillResults.sol";
-import "./libs/LibExchangeErrors.sol";
 import "./mixins/MExchangeCore.sol";
 import "./mixins/MMatchOrders.sol";
 import "./mixins/MTransactions.sol";
@@ -28,14 +26,11 @@ import "./mixins/MAssetProxyDispatcher.sol";
 contract MixinMatchOrders is
     LibConstants,
     LibMath,
-    LibExchangeErrors,
     MAssetProxyDispatcher,
     MExchangeCore,
     MMatchOrders,
     MTransactions
 {
-    using LibBytes for bytes;
-
     /// @dev Match two complementary orders that have a profitable spread.
     ///      Each order is filled at their respective price point. However, the calculations are
     ///      carried out as though the orders are both being filled at the right order's price point.
@@ -144,7 +139,7 @@ contract MixinMatchOrders is
         require(
             safeMul(leftOrder.makerAssetAmount, rightOrder.makerAssetAmount) >=
             safeMul(leftOrder.takerAssetAmount, rightOrder.takerAssetAmount),
-            NEGATIVE_SPREAD_REQUIRED
+            "NEGATIVE_SPREAD_REQUIRED"
         );
     }
 
@@ -242,27 +237,22 @@ contract MixinMatchOrders is
     )
         private
     {
-        uint8 leftMakerAssetProxyId = uint8(leftOrder.makerAssetData.popLastByte());
-        uint8 rightMakerAssetProxyId = uint8(rightOrder.makerAssetData.popLastByte());
         bytes memory zrxAssetData = ZRX_ASSET_DATA;
         // Order makers and taker
         dispatchTransferFrom(
             leftOrder.makerAssetData,
-            leftMakerAssetProxyId,
             leftOrder.makerAddress,
             rightOrder.makerAddress,
             matchedFillResults.right.takerAssetFilledAmount
         );
         dispatchTransferFrom(
             rightOrder.makerAssetData,
-            rightMakerAssetProxyId,
             rightOrder.makerAddress,
             leftOrder.makerAddress,
             matchedFillResults.left.takerAssetFilledAmount
         );
         dispatchTransferFrom(
             leftOrder.makerAssetData,
-            leftMakerAssetProxyId,
             leftOrder.makerAddress,
             takerAddress,
             matchedFillResults.leftMakerAssetSpreadAmount
@@ -271,14 +261,12 @@ contract MixinMatchOrders is
         // Maker fees
         dispatchTransferFrom(
             zrxAssetData,
-            ZRX_PROXY_ID,
             leftOrder.makerAddress,
             leftOrder.feeRecipientAddress,
             matchedFillResults.left.makerFeePaid
         );
         dispatchTransferFrom(
             zrxAssetData,
-            ZRX_PROXY_ID,
             rightOrder.makerAddress,
             rightOrder.feeRecipientAddress,
             matchedFillResults.right.makerFeePaid
@@ -288,7 +276,6 @@ contract MixinMatchOrders is
         if (leftOrder.feeRecipientAddress == rightOrder.feeRecipientAddress) {
             dispatchTransferFrom(
                 zrxAssetData,
-                ZRX_PROXY_ID,
                 takerAddress,
                 leftOrder.feeRecipientAddress,
                 safeAdd(
@@ -299,14 +286,12 @@ contract MixinMatchOrders is
         } else {
             dispatchTransferFrom(
                 zrxAssetData,
-                ZRX_PROXY_ID,
                 takerAddress,
                 leftOrder.feeRecipientAddress,
                 matchedFillResults.left.takerFeePaid
             );
             dispatchTransferFrom(
                 zrxAssetData,
-                ZRX_PROXY_ID,
                 takerAddress,
                 rightOrder.feeRecipientAddress,
                 matchedFillResults.right.takerFeePaid
diff --git a/packages/contracts/src/contracts/current/protocol/Exchange/MixinSignatureValidator.sol b/packages/contracts/src/2.0.0/protocol/Exchange/MixinSignatureValidator.sol
index cbb55bfce..29172057a 100644
--- a/packages/contracts/src/contracts/current/protocol/Exchange/MixinSignatureValidator.sol
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/MixinSignatureValidator.sol
@@ -19,23 +19,17 @@
 pragma solidity ^0.4.24;
 
 import "../../utils/LibBytes/LibBytes.sol";
-import "./libs/LibExchangeErrors.sol";
 import "./mixins/MSignatureValidator.sol";
 import "./mixins/MTransactions.sol";
 import "./interfaces/IWallet.sol";
 import "./interfaces/IValidator.sol";
 
 contract MixinSignatureValidator is
-    LibExchangeErrors,
     MSignatureValidator,
     MTransactions
 {
     using LibBytes for bytes;
     
-    // Personal message headers
-    string constant ETH_PERSONAL_MESSAGE = "\x19Ethereum Signed Message:\n32";
-    string constant TREZOR_PERSONAL_MESSAGE = "\x19Ethereum Signed Message:\n\x20";
-
     // Mapping of hash => signer => signed
     mapping (bytes32 => mapping (address => bool)) public preSigned;
 
@@ -59,7 +53,7 @@ contract MixinSignatureValidator is
                 signerAddress,
                 signature
             ),
-            INVALID_SIGNATURE
+            "INVALID_SIGNATURE"
         );
         preSigned[hash][signerAddress] = true;
     }
@@ -99,14 +93,14 @@ contract MixinSignatureValidator is
         // TODO: Domain separation: make hash depend on role. (Taker sig should not be valid as maker sig, etc.)
         require(
             signature.length > 0,
-            LENGTH_GREATER_THAN_0_REQUIRED
+            "LENGTH_GREATER_THAN_0_REQUIRED"
         );
 
         // Ensure signature is supported
         uint8 signatureTypeRaw = uint8(signature.popLastByte());
         require(
             signatureTypeRaw < uint8(SignatureType.NSignatureTypes),
-            SIGNATURE_UNSUPPORTED
+            "SIGNATURE_UNSUPPORTED"
         );
 
         // Pop last byte off of signature byte array.
@@ -124,7 +118,7 @@ contract MixinSignatureValidator is
         // it an explicit option. This aids testing and analysis. It is
         // also the initialization value for the enum type.
         if (signatureType == SignatureType.Illegal) {
-            revert(SIGNATURE_ILLEGAL);
+            revert("SIGNATURE_ILLEGAL");
 
         // Always invalid signature.
         // Like Illegal, this is always implicitly available and therefore
@@ -133,7 +127,7 @@ contract MixinSignatureValidator is
         } else if (signatureType == SignatureType.Invalid) {
             require(
                 signature.length == 0,
-                LENGTH_0_REQUIRED
+                "LENGTH_0_REQUIRED"
             );
             isValid = false;
             return isValid;
@@ -142,7 +136,7 @@ contract MixinSignatureValidator is
         } else if (signatureType == SignatureType.EIP712) {
             require(
                 signature.length == 65,
-                LENGTH_65_REQUIRED
+                "LENGTH_65_REQUIRED"
             );
             v = uint8(signature[0]);
             r = signature.readBytes32(1);
@@ -155,13 +149,16 @@ contract MixinSignatureValidator is
         } else if (signatureType == SignatureType.EthSign) {
             require(
                 signature.length == 65,
-                LENGTH_65_REQUIRED
+                "LENGTH_65_REQUIRED"
             );
             v = uint8(signature[0]);
             r = signature.readBytes32(1);
             s = signature.readBytes32(33);
             recovered = ecrecover(
-                keccak256(abi.encodePacked(ETH_PERSONAL_MESSAGE, hash)),
+                keccak256(abi.encodePacked(
+                    "\x19Ethereum Signed Message:\n32",
+                    hash
+                )),
                 v,
                 r,
                 s
@@ -180,7 +177,7 @@ contract MixinSignatureValidator is
         } else if (signatureType == SignatureType.Caller) {
             require(
                 signature.length == 0,
-                LENGTH_0_REQUIRED
+                "LENGTH_0_REQUIRED"
             );
             isValid = signerAddress == msg.sender;
             return isValid;
@@ -230,13 +227,16 @@ contract MixinSignatureValidator is
         } else if (signatureType == SignatureType.Trezor) {
             require(
                 signature.length == 65,
-                LENGTH_65_REQUIRED
+                "LENGTH_65_REQUIRED"
             );
             v = uint8(signature[0]);
             r = signature.readBytes32(1);
             s = signature.readBytes32(33);
             recovered = ecrecover(
-                keccak256(abi.encodePacked(TREZOR_PERSONAL_MESSAGE, hash)),
+                keccak256(abi.encodePacked(
+                    "\x19Ethereum Signed Message:\n\x20",
+                    hash
+                )),
                 v,
                 r,
                 s
@@ -250,6 +250,6 @@ contract MixinSignatureValidator is
         // that we currently support. In this case returning false
         // may lead the caller to incorrectly believe that the
         // signature was invalid.)
-        revert(SIGNATURE_UNSUPPORTED);
+        revert("SIGNATURE_UNSUPPORTED");
     }
 }
diff --git a/packages/contracts/src/contracts/current/protocol/Exchange/MixinTransactions.sol b/packages/contracts/src/2.0.0/protocol/Exchange/MixinTransactions.sol
index 20a4a12df..31f7f2847 100644
--- a/packages/contracts/src/contracts/current/protocol/Exchange/MixinTransactions.sol
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/MixinTransactions.sol
@@ -20,12 +20,10 @@ pragma solidity ^0.4.24;
 import "./libs/LibExchangeErrors.sol";
 import "./mixins/MSignatureValidator.sol";
 import "./mixins/MTransactions.sol";
-import "./libs/LibExchangeErrors.sol";
 import "./libs/LibEIP712.sol";
 
 contract MixinTransactions is
     LibEIP712,
-    LibExchangeErrors,
     MSignatureValidator,
     MTransactions
 {
@@ -62,6 +60,13 @@ contract MixinTransactions is
     {
         bytes32 schemaHash = EIP712_ZEROEX_TRANSACTION_SCHEMA_HASH;
         bytes32 dataHash = keccak256(data);
+        // Assembly for more efficiently computing:
+        // keccak256(abi.encode(
+        //   EIP712_ZEROEX_TRANSACTION_SCHEMA_HASH,
+        //   salt,
+        //   signerAddress,
+        //   keccak256(data)
+        //  ));
         assembly {
             let memPtr := mload(64)
             mstore(memPtr, schemaHash)
@@ -90,7 +95,7 @@ contract MixinTransactions is
         // Prevent reentrancy
         require(
             currentContextAddress == address(0),
-            REENTRANCY_ILLEGAL
+            "REENTRANCY_ILLEGAL"
         );
 
         bytes32 transactionHash = hashEIP712Message(hashZeroExTransaction(
@@ -102,7 +107,7 @@ contract MixinTransactions is
         // Validate transaction has not been executed
         require(
             !transactions[transactionHash],
-            INVALID_TX_HASH
+            "INVALID_TX_HASH"
         );
 
         // Transaction always valid if signer is sender of transaction
@@ -114,7 +119,7 @@ contract MixinTransactions is
                     signerAddress,
                     signature
                 ),
-                INVALID_TX_SIGNATURE
+                "INVALID_TX_SIGNATURE"
             );
 
             // Set the current transaction signer
@@ -125,7 +130,7 @@ contract MixinTransactions is
         transactions[transactionHash] = true;
         require(
             address(this).delegatecall(data),
-            FAILED_EXECUTION
+            "FAILED_EXECUTION"
         );
 
         // Reset current transaction signer
diff --git a/packages/contracts/src/contracts/current/protocol/Exchange/MixinWrapperFunctions.sol b/packages/contracts/src/2.0.0/protocol/Exchange/MixinWrapperFunctions.sol
index 724f95518..00668ca43 100644
--- a/packages/contracts/src/contracts/current/protocol/Exchange/MixinWrapperFunctions.sol
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/MixinWrapperFunctions.sol
@@ -22,13 +22,11 @@ pragma experimental ABIEncoderV2;
 import "./libs/LibMath.sol";
 import "./libs/LibOrder.sol";
 import "./libs/LibFillResults.sol";
-import "./libs/LibExchangeErrors.sol";
 import "./mixins/MExchangeCore.sol";
 
 contract MixinWrapperFunctions is
     LibMath,
     LibFillResults,
-    LibExchangeErrors,
     MExchangeCore
 {
     /// @dev Fills the input order. Reverts if exact takerAssetFillAmount not filled.
@@ -50,7 +48,7 @@ contract MixinWrapperFunctions is
         );
         require(
             fillResults.takerAssetFilledAmount == takerAssetFillAmount,
-            COMPLETE_FILL_FAILED
+            "COMPLETE_FILL_FAILED"
         );
         return fillResults;
     }
@@ -366,14 +364,6 @@ contract MixinWrapperFunctions is
                 signatures[i]
             );
 
-            // HACK: the proxyId is "popped" from the byte array before a fill is settled
-            // by subtracting from the length of the array. Since the popped byte is 
-            // still in memory, we can "unpop" it by incrementing the length of the byte array.
-            assembly {
-                let len := mload(takerAssetData)
-                mstore(takerAssetData, add(len, 1))
-            }
-
             // Update amounts filled and fees paid by maker and taker
             addFillResults(totalFillResults, singleFillResults);
 
@@ -467,14 +457,6 @@ contract MixinWrapperFunctions is
                 signatures[i]
             );
 
-            // HACK: the proxyId is "popped" from the byte array before a fill is settled
-            // by subtracting from the length of the array. Since the popped byte is 
-            // still in memory, we can "unpop" it by incrementing the length of the byte array.
-            assembly {
-                let len := mload(makerAssetData)
-                mstore(makerAssetData, add(len, 1))
-            }
-
             // Update amounts filled and fees paid by maker and taker
             addFillResults(totalFillResults, singleFillResults);
 
diff --git a/packages/contracts/src/contracts/current/protocol/Exchange/interfaces/IAssetProxyDispatcher.sol b/packages/contracts/src/2.0.0/protocol/Exchange/interfaces/IAssetProxyDispatcher.sol
index 2c331dc34..66f3b5796 100644
--- a/packages/contracts/src/contracts/current/protocol/Exchange/interfaces/IAssetProxyDispatcher.sol
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/interfaces/IAssetProxyDispatcher.sol
@@ -20,22 +20,16 @@ pragma solidity ^0.4.24;
 
 contract IAssetProxyDispatcher {
 
-    /// @dev Registers an asset proxy to an asset proxy id.
-    ///      An id can only be assigned to a single proxy at a given time.
-    /// @param assetProxyId Id to register`newAssetProxy` under.
-    /// @param newAssetProxy Address of new asset proxy to register, or 0x0 to unset assetProxyId.
-    /// @param oldAssetProxy Existing asset proxy to overwrite, or 0x0 if assetProxyId is currently unused.
-    function registerAssetProxy(
-        uint8 assetProxyId,
-        address newAssetProxy,
-        address oldAssetProxy
-    )
+    /// @dev Registers an asset proxy to its asset proxy id.
+    ///      Once an asset proxy is registered, it cannot be unregistered.
+    /// @param assetProxy Address of new asset proxy to register.
+    function registerAssetProxy(address assetProxy)
         external;
 
     /// @dev Gets an asset proxy.
     /// @param assetProxyId Id of the asset proxy.
     /// @return The asset proxy registered to assetProxyId. Returns 0x0 if no proxy is registered.
-    function getAssetProxy(uint8 assetProxyId)
+    function getAssetProxy(bytes4 assetProxyId)
         external
         view
         returns (address);
diff --git a/packages/contracts/src/contracts/current/protocol/Exchange/interfaces/IExchange.sol b/packages/contracts/src/2.0.0/protocol/Exchange/interfaces/IExchange.sol
index 9f21c18d7..9f21c18d7 100644
--- a/packages/contracts/src/contracts/current/protocol/Exchange/interfaces/IExchange.sol
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/interfaces/IExchange.sol
diff --git a/packages/contracts/src/contracts/current/protocol/Exchange/interfaces/IExchangeCore.sol b/packages/contracts/src/2.0.0/protocol/Exchange/interfaces/IExchangeCore.sol
index 98222f33f..98222f33f 100644
--- a/packages/contracts/src/contracts/current/protocol/Exchange/interfaces/IExchangeCore.sol
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/interfaces/IExchangeCore.sol
diff --git a/packages/contracts/src/contracts/current/protocol/Exchange/interfaces/IMatchOrders.sol b/packages/contracts/src/2.0.0/protocol/Exchange/interfaces/IMatchOrders.sol
index df009d063..df009d063 100644
--- a/packages/contracts/src/contracts/current/protocol/Exchange/interfaces/IMatchOrders.sol
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/interfaces/IMatchOrders.sol
diff --git a/packages/contracts/src/contracts/current/protocol/Exchange/interfaces/ISignatureValidator.sol b/packages/contracts/src/2.0.0/protocol/Exchange/interfaces/ISignatureValidator.sol
index 511463309..511463309 100644
--- a/packages/contracts/src/contracts/current/protocol/Exchange/interfaces/ISignatureValidator.sol
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/interfaces/ISignatureValidator.sol
diff --git a/packages/contracts/src/contracts/current/protocol/Exchange/interfaces/ITransactions.sol b/packages/contracts/src/2.0.0/protocol/Exchange/interfaces/ITransactions.sol
index a7cab8f55..a7cab8f55 100644
--- a/packages/contracts/src/contracts/current/protocol/Exchange/interfaces/ITransactions.sol
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/interfaces/ITransactions.sol
diff --git a/packages/contracts/src/contracts/current/protocol/Exchange/interfaces/IValidator.sol b/packages/contracts/src/2.0.0/protocol/Exchange/interfaces/IValidator.sol
index 0b1796a66..0b1796a66 100644
--- a/packages/contracts/src/contracts/current/protocol/Exchange/interfaces/IValidator.sol
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/interfaces/IValidator.sol
diff --git a/packages/contracts/src/contracts/current/protocol/Exchange/interfaces/IWallet.sol b/packages/contracts/src/2.0.0/protocol/Exchange/interfaces/IWallet.sol
index c86a2c057..c86a2c057 100644
--- a/packages/contracts/src/contracts/current/protocol/Exchange/interfaces/IWallet.sol
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/interfaces/IWallet.sol
diff --git a/packages/contracts/src/contracts/current/protocol/Exchange/interfaces/IWrapperFunctions.sol b/packages/contracts/src/2.0.0/protocol/Exchange/interfaces/IWrapperFunctions.sol
index 84bb683bc..84bb683bc 100644
--- a/packages/contracts/src/contracts/current/protocol/Exchange/interfaces/IWrapperFunctions.sol
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/interfaces/IWrapperFunctions.sol
diff --git a/packages/contracts/src/contracts/current/protocol/Exchange/libs/LibConstants.sol b/packages/contracts/src/2.0.0/protocol/Exchange/libs/LibConstants.sol
index 4a9452448..488ca956c 100644
--- a/packages/contracts/src/contracts/current/protocol/Exchange/libs/LibConstants.sol
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/libs/LibConstants.sol
@@ -25,9 +25,6 @@ contract LibConstants {
     //        not constant to make testing easier.
     bytes public ZRX_ASSET_DATA;
 
-    // Proxy Id for ZRX token.
-    uint8 constant ZRX_PROXY_ID = 1;
-
     // @TODO: Remove when we deploy.
     constructor (bytes memory zrxAssetData)
         public
diff --git a/packages/contracts/src/contracts/current/protocol/Exchange/libs/LibEIP712.sol b/packages/contracts/src/2.0.0/protocol/Exchange/libs/LibEIP712.sol
index b983347a4..b983347a4 100644
--- a/packages/contracts/src/contracts/current/protocol/Exchange/libs/LibEIP712.sol
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/libs/LibEIP712.sol
diff --git a/packages/contracts/src/contracts/current/protocol/Exchange/libs/LibExchangeErrors.sol b/packages/contracts/src/2.0.0/protocol/Exchange/libs/LibExchangeErrors.sol
index a43f0f927..01aa78a1d 100644
--- a/packages/contracts/src/contracts/current/protocol/Exchange/libs/LibExchangeErrors.sol
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/libs/LibExchangeErrors.sol
@@ -18,7 +18,10 @@
 
 pragma solidity ^0.4.24;
 
+/// @dev This contract documents the revert reasons used in the Exchange contract.
+/// This contract is intended to serve as a reference, but is not actually used for efficiency reasons.
 contract LibExchangeErrors {
+
     /// Order validation errors ///
     string constant ORDER_UNFILLABLE = "ORDER_UNFILLABLE";                              // Order cannot be filled.
     string constant INVALID_MAKER = "INVALID_MAKER";                                    // Invalid makerAddress.
@@ -51,14 +54,15 @@ contract LibExchangeErrors {
     string constant FAILED_EXECUTION = "FAILED_EXECUTION";                              // Transaction execution failed. 
     
     /// registerAssetProxy errors ///
-    string constant ASSET_PROXY_MISMATCH = "ASSET_PROXY_MISMATCH";                      // oldAssetProxy proxy does not match currentAssetProxy. 
-    string constant ASSET_PROXY_ID_MISMATCH = "ASSET_PROXY_ID_MISMATCH";                // newAssetProxyId does not match given assetProxyId.
+    string constant ASSET_PROXY_ALREADY_EXISTS = "ASSET_PROXY_ALREADY_EXISTS";          // AssetProxy with same id already exists.
 
     /// dispatchTransferFrom errors ///
     string constant ASSET_PROXY_DOES_NOT_EXIST = "ASSET_PROXY_DOES_NOT_EXIST";          // No assetProxy registered at given id.
+    string constant TRANSFER_FAILED = "TRANSFER_FAILED";                                // Asset transfer unsuccesful.
 
     /// Length validation errors ///
     string constant LENGTH_GREATER_THAN_0_REQUIRED = "LENGTH_GREATER_THAN_0_REQUIRED";  // Byte array must have a length greater than 0.
+    string constant LENGTH_GREATER_THAN_3_REQUIRED = "LENGTH_GREATER_THAN_3_REQUIRED";  // Byte array must have a length greater than 3.
     string constant LENGTH_0_REQUIRED = "LENGTH_0_REQUIRED";                            // Byte array must have a length of 0.
     string constant LENGTH_65_REQUIRED = "LENGTH_65_REQUIRED";                          // Byte array must have a length of 65.
 }
diff --git a/packages/contracts/src/contracts/current/protocol/Exchange/libs/LibFillResults.sol b/packages/contracts/src/2.0.0/protocol/Exchange/libs/LibFillResults.sol
index 63f1b8c87..63f1b8c87 100644
--- a/packages/contracts/src/contracts/current/protocol/Exchange/libs/LibFillResults.sol
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/libs/LibFillResults.sol
diff --git a/packages/contracts/src/contracts/current/protocol/Exchange/libs/LibMath.sol b/packages/contracts/src/2.0.0/protocol/Exchange/libs/LibMath.sol
index 233547b9f..bfe2fd33f 100644
--- a/packages/contracts/src/contracts/current/protocol/Exchange/libs/LibMath.sol
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/libs/LibMath.sol
@@ -23,7 +23,6 @@ import "../../../utils/SafeMath/SafeMath.sol";
 contract LibMath is
     SafeMath
 {
-    string constant ROUNDING_ERROR_ON_PARTIAL_AMOUNT = "A rounding error occurred when calculating partial transfer amounts.";
 
     /// @dev Calculates partial value given a numerator and denominator.
     /// @param numerator Numerator.
diff --git a/packages/contracts/src/contracts/current/protocol/Exchange/libs/LibOrder.sol b/packages/contracts/src/2.0.0/protocol/Exchange/libs/LibOrder.sol
index f3f1e9277..954f94f76 100644
--- a/packages/contracts/src/contracts/current/protocol/Exchange/libs/LibOrder.sol
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/libs/LibOrder.sol
@@ -98,6 +98,21 @@ contract LibOrder is
         bytes32 schemaHash = EIP712_ORDER_SCHEMA_HASH;
         bytes32 makerAssetDataHash = keccak256(order.makerAssetData);
         bytes32 takerAssetDataHash = keccak256(order.takerAssetData);
+        // Assembly for more efficiently computing:
+        //   keccak256(abi.encode(
+        //       order.makerAddress,
+        //       order.takerAddress,
+        //       order.feeRecipientAddress,
+        //       order.senderAddress,
+        //       order.makerAssetAmount,
+        //       order.takerAssetAmount,
+        //       order.makerFee,
+        //       order.takerFee,
+        //       order.expirationTimeSeconds,
+        //       order.salt,
+        //       keccak256(order.makerAssetData),
+        //       keccak256(order.takerAssetData)
+        //   ));
         assembly {
             // Backup
             let temp1 := mload(sub(order,  32))
diff --git a/packages/contracts/src/contracts/current/protocol/Exchange/mixins/MAssetProxyDispatcher.sol b/packages/contracts/src/2.0.0/protocol/Exchange/mixins/MAssetProxyDispatcher.sol
index 788f42c60..5bf59c6ce 100644
--- a/packages/contracts/src/contracts/current/protocol/Exchange/mixins/MAssetProxyDispatcher.sol
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/mixins/MAssetProxyDispatcher.sol
@@ -26,21 +26,18 @@ contract MAssetProxyDispatcher is
 {
 
     // Logs registration of new asset proxy
-    event AssetProxySet(
-        uint8 id,               // Id of new registered AssetProxy.
-        address newAssetProxy,  // Address of new registered AssetProxy.
-        address oldAssetProxy   // Address of AssetProxy that was overwritten at given id (or null address).
+    event AssetProxyRegistered(
+        bytes4 id,              // Id of new registered AssetProxy.
+        address assetProxy      // Address of new registered AssetProxy.
     );
 
     /// @dev Forwards arguments to assetProxy and calls `transferFrom`. Either succeeds or throws.
-    /// @param assetData Byte array encoded for the respective asset proxy.
-    /// @param assetProxyId Id of assetProxy to dispach to.
+    /// @param assetData Byte array encoded for the asset.
     /// @param from Address to transfer token from.
     /// @param to Address to transfer token to.
     /// @param amount Amount of token to transfer.
     function dispatchTransferFrom(
         bytes memory assetData,
-        uint8 assetProxyId,
         address from,
         address to,
         uint256 amount
diff --git a/packages/contracts/src/contracts/current/protocol/Exchange/mixins/MExchangeCore.sol b/packages/contracts/src/2.0.0/protocol/Exchange/mixins/MExchangeCore.sol
index 6e406e1c4..6e406e1c4 100644
--- a/packages/contracts/src/contracts/current/protocol/Exchange/mixins/MExchangeCore.sol
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/mixins/MExchangeCore.sol
diff --git a/packages/contracts/src/contracts/current/protocol/Exchange/mixins/MMatchOrders.sol b/packages/contracts/src/2.0.0/protocol/Exchange/mixins/MMatchOrders.sol
index abe7c3596..abe7c3596 100644
--- a/packages/contracts/src/contracts/current/protocol/Exchange/mixins/MMatchOrders.sol
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/mixins/MMatchOrders.sol
diff --git a/packages/contracts/src/contracts/current/protocol/Exchange/mixins/MSignatureValidator.sol b/packages/contracts/src/2.0.0/protocol/Exchange/mixins/MSignatureValidator.sol
index 6cc1d7a10..6cc1d7a10 100644
--- a/packages/contracts/src/contracts/current/protocol/Exchange/mixins/MSignatureValidator.sol
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/mixins/MSignatureValidator.sol
diff --git a/packages/contracts/src/contracts/current/protocol/Exchange/mixins/MTransactions.sol b/packages/contracts/src/2.0.0/protocol/Exchange/mixins/MTransactions.sol
index e2f89de01..e2f89de01 100644
--- a/packages/contracts/src/contracts/current/protocol/Exchange/mixins/MTransactions.sol
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/mixins/MTransactions.sol
diff --git a/packages/contracts/src/contracts/current/test/DummyERC20Token/DummyERC20Token.sol b/packages/contracts/src/2.0.0/test/DummyERC20Token/DummyERC20Token.sol
index b2fe2df06..b2fe2df06 100644
--- a/packages/contracts/src/contracts/current/test/DummyERC20Token/DummyERC20Token.sol
+++ b/packages/contracts/src/2.0.0/test/DummyERC20Token/DummyERC20Token.sol
diff --git a/packages/contracts/src/contracts/current/test/DummyERC721Receiver/DummyERC721Receiver.sol b/packages/contracts/src/2.0.0/test/DummyERC721Receiver/DummyERC721Receiver.sol
index c584d0b54..c584d0b54 100644
--- a/packages/contracts/src/contracts/current/test/DummyERC721Receiver/DummyERC721Receiver.sol
+++ b/packages/contracts/src/2.0.0/test/DummyERC721Receiver/DummyERC721Receiver.sol
diff --git a/packages/contracts/src/contracts/current/test/DummyERC721Token/DummyERC721Token.sol b/packages/contracts/src/2.0.0/test/DummyERC721Token/DummyERC721Token.sol
index 5503eb2f2..78ea96447 100644
--- a/packages/contracts/src/contracts/current/test/DummyERC721Token/DummyERC721Token.sol
+++ b/packages/contracts/src/2.0.0/test/DummyERC721Token/DummyERC721Token.sol
@@ -56,4 +56,20 @@ contract DummyERC721Token is
         );
         _mint(to, tokenId);
     }
+
+    /**
+    * @dev Function to burn a token
+    * @dev Reverts if the given token ID doesn't exist
+    * @param tokenId uint256 ID of the token to be minted by the msg.sender
+    */
+    function burn(address owner, uint256 tokenId)
+        public
+        onlyOwner
+    {
+        require(
+            exists(tokenId),
+            "Token with tokenId does not exist."
+        );
+        _burn(owner, tokenId);
+    }
 }
diff --git a/packages/contracts/src/contracts/current/test/ExchangeWrapper/ExchangeWrapper.sol b/packages/contracts/src/2.0.0/test/ExchangeWrapper/ExchangeWrapper.sol
index 5baaf6e5a..5baaf6e5a 100644
--- a/packages/contracts/src/contracts/current/test/ExchangeWrapper/ExchangeWrapper.sol
+++ b/packages/contracts/src/2.0.0/test/ExchangeWrapper/ExchangeWrapper.sol
diff --git a/packages/contracts/src/contracts/current/test/Mintable/Mintable.sol b/packages/contracts/src/2.0.0/test/Mintable/Mintable.sol
index a91bfee9e..a91bfee9e 100644
--- a/packages/contracts/src/contracts/current/test/Mintable/Mintable.sol
+++ b/packages/contracts/src/2.0.0/test/Mintable/Mintable.sol
diff --git a/packages/contracts/src/contracts/current/test/TestAssetProxyDispatcher/TestAssetProxyDispatcher.sol b/packages/contracts/src/2.0.0/test/TestAssetProxyDispatcher/TestAssetProxyDispatcher.sol
index d469a07f0..2ae69e0ef 100644
--- a/packages/contracts/src/contracts/current/test/TestAssetProxyDispatcher/TestAssetProxyDispatcher.sol
+++ b/packages/contracts/src/2.0.0/test/TestAssetProxyDispatcher/TestAssetProxyDispatcher.sol
@@ -24,12 +24,11 @@ import "../../protocol/Exchange/MixinAssetProxyDispatcher.sol";
 contract TestAssetProxyDispatcher is MixinAssetProxyDispatcher {
     function publicDispatchTransferFrom(
         bytes memory assetData,
-        uint8 assetProxyId,
         address from,
         address to,
         uint256 amount)
         public
     {
-        dispatchTransferFrom(assetData, assetProxyId, from, to, amount);
+        dispatchTransferFrom(assetData, from, to, amount);
     }
 }
diff --git a/packages/contracts/src/contracts/current/test/TestAssetProxyOwner/TestAssetProxyOwner.sol b/packages/contracts/src/2.0.0/test/TestAssetProxyOwner/TestAssetProxyOwner.sol
index 2abcd17a0..2abcd17a0 100644
--- a/packages/contracts/src/contracts/current/test/TestAssetProxyOwner/TestAssetProxyOwner.sol
+++ b/packages/contracts/src/2.0.0/test/TestAssetProxyOwner/TestAssetProxyOwner.sol
diff --git a/packages/contracts/src/contracts/current/test/TestLibBytes/TestLibBytes.sol b/packages/contracts/src/2.0.0/test/TestLibBytes/TestLibBytes.sol
index f45faaf36..f45faaf36 100644
--- a/packages/contracts/src/contracts/current/test/TestLibBytes/TestLibBytes.sol
+++ b/packages/contracts/src/2.0.0/test/TestLibBytes/TestLibBytes.sol
diff --git a/packages/contracts/src/contracts/current/test/TestLibs/TestLibs.sol b/packages/contracts/src/2.0.0/test/TestLibs/TestLibs.sol
index 010080703..010080703 100644
--- a/packages/contracts/src/contracts/current/test/TestLibs/TestLibs.sol
+++ b/packages/contracts/src/2.0.0/test/TestLibs/TestLibs.sol
diff --git a/packages/contracts/src/contracts/current/test/TestSignatureValidator/TestSignatureValidator.sol b/packages/contracts/src/2.0.0/test/TestSignatureValidator/TestSignatureValidator.sol
index 0f84678cf..0f84678cf 100644
--- a/packages/contracts/src/contracts/current/test/TestSignatureValidator/TestSignatureValidator.sol
+++ b/packages/contracts/src/2.0.0/test/TestSignatureValidator/TestSignatureValidator.sol
diff --git a/packages/contracts/src/contracts/current/test/TestValidator/TestValidator.sol b/packages/contracts/src/2.0.0/test/TestValidator/TestValidator.sol
index f9271bf7a..f9271bf7a 100644
--- a/packages/contracts/src/contracts/current/test/TestValidator/TestValidator.sol
+++ b/packages/contracts/src/2.0.0/test/TestValidator/TestValidator.sol
diff --git a/packages/contracts/src/contracts/current/test/TestWallet/TestWallet.sol b/packages/contracts/src/2.0.0/test/TestWallet/TestWallet.sol
index 17dee9e9c..17dee9e9c 100644
--- a/packages/contracts/src/contracts/current/test/TestWallet/TestWallet.sol
+++ b/packages/contracts/src/2.0.0/test/TestWallet/TestWallet.sol
diff --git a/packages/contracts/src/contracts/current/test/Whitelist/Whitelist.sol b/packages/contracts/src/2.0.0/test/Whitelist/Whitelist.sol
index d35815474..8b52858b1 100644
--- a/packages/contracts/src/contracts/current/test/Whitelist/Whitelist.sol
+++ b/packages/contracts/src/2.0.0/test/Whitelist/Whitelist.sol
@@ -23,13 +23,13 @@ import "../../protocol/Exchange/interfaces/IExchange.sol";
 import "../../protocol/Exchange/libs/LibOrder.sol";
 import "../../utils/Ownable/Ownable.sol";
 
-contract Whitelist is 
+contract Whitelist is
     Ownable
 {
     // Revert reasons
-    string constant MAKER_NOT_WHITELISTED = "Maker address not whitelisted.";
-    string constant TAKER_NOT_WHITELISTED = "Taker address not whitelisted.";
-    string constant INVALID_SENDER = "Sender must equal transaction origin.";
+    string constant MAKER_NOT_WHITELISTED = "MAKER_NOT_WHITELISTED"; // Maker address not whitelisted.
+    string constant TAKER_NOT_WHITELISTED = "TAKER_NOT_WHITELISTED"; // Taker address not whitelisted.
+    string constant INVALID_SENDER = "INVALID_SENDER"; // Sender must equal transaction origin.
 
     // Mapping of address => whitelist status.
     mapping (address => bool) public isWhitelisted;
@@ -77,7 +77,7 @@ contract Whitelist is
         public
     {
         address takerAddress = msg.sender;
-    
+
         // This contract must be the entry point for the transaction.
         require(
             takerAddress == tx.origin,
diff --git a/packages/contracts/src/contracts/current/tokens/ERC20Token/ERC20Token.sol b/packages/contracts/src/2.0.0/tokens/ERC20Token/ERC20Token.sol
index f0bcdafef..b6961a6ec 100644
--- a/packages/contracts/src/contracts/current/tokens/ERC20Token/ERC20Token.sol
+++ b/packages/contracts/src/2.0.0/tokens/ERC20Token/ERC20Token.sol
@@ -23,8 +23,8 @@ import "./IERC20Token.sol";
 
 contract ERC20Token is IERC20Token {
 
-    string constant INSUFFICIENT_BALANCE = "Insufficient balance to complete transfer.";
-    string constant INSUFFICIENT_ALLOWANCE = "Insufficient allowance to complete transfer.";
+    string constant INSUFFICIENT_BALANCE = "ERC20_INSUFFICIENT_BALANCE";
+    string constant INSUFFICIENT_ALLOWANCE = "ERC20_INSUFFICIENT_ALLOWANCE";
     string constant OVERFLOW = "Transfer would result in an overflow.";
 
     mapping (address => uint256) balances;
@@ -97,4 +97,3 @@ contract ERC20Token is IERC20Token {
         return allowed[_owner][_spender];
     }
 }
-
diff --git a/packages/contracts/src/contracts/current/tokens/ERC20Token/IERC20Token.sol b/packages/contracts/src/2.0.0/tokens/ERC20Token/IERC20Token.sol
index eb879b6a8..eb879b6a8 100644
--- a/packages/contracts/src/contracts/current/tokens/ERC20Token/IERC20Token.sol
+++ b/packages/contracts/src/2.0.0/tokens/ERC20Token/IERC20Token.sol
diff --git a/packages/contracts/src/contracts/current/tokens/ERC721Token/ERC721Token.sol b/packages/contracts/src/2.0.0/tokens/ERC721Token/ERC721Token.sol
index 41ba149e3..41ba149e3 100644
--- a/packages/contracts/src/contracts/current/tokens/ERC721Token/ERC721Token.sol
+++ b/packages/contracts/src/2.0.0/tokens/ERC721Token/ERC721Token.sol
diff --git a/packages/contracts/src/contracts/current/tokens/ERC721Token/IERC721Receiver.sol b/packages/contracts/src/2.0.0/tokens/ERC721Token/IERC721Receiver.sol
index b0fff3c90..b0fff3c90 100644
--- a/packages/contracts/src/contracts/current/tokens/ERC721Token/IERC721Receiver.sol
+++ b/packages/contracts/src/2.0.0/tokens/ERC721Token/IERC721Receiver.sol
diff --git a/packages/contracts/src/contracts/current/tokens/ERC721Token/IERC721Token.sol b/packages/contracts/src/2.0.0/tokens/ERC721Token/IERC721Token.sol
index 345712d67..345712d67 100644
--- a/packages/contracts/src/contracts/current/tokens/ERC721Token/IERC721Token.sol
+++ b/packages/contracts/src/2.0.0/tokens/ERC721Token/IERC721Token.sol
diff --git a/packages/contracts/src/contracts/current/tokens/UnlimitedAllowanceToken/UnlimitedAllowanceToken.sol b/packages/contracts/src/2.0.0/tokens/UnlimitedAllowanceToken/UnlimitedAllowanceToken.sol
index f62602ab3..f62602ab3 100644
--- a/packages/contracts/src/contracts/current/tokens/UnlimitedAllowanceToken/UnlimitedAllowanceToken.sol
+++ b/packages/contracts/src/2.0.0/tokens/UnlimitedAllowanceToken/UnlimitedAllowanceToken.sol
diff --git a/packages/contracts/src/contracts/current/tokens/WETH9/WETH9.sol b/packages/contracts/src/2.0.0/tokens/WETH9/WETH9.sol
index 733ca414b..733ca414b 100644
--- a/packages/contracts/src/contracts/current/tokens/WETH9/WETH9.sol
+++ b/packages/contracts/src/2.0.0/tokens/WETH9/WETH9.sol
diff --git a/packages/contracts/src/contracts/current/tokens/ZRXToken/ZRXToken.sol b/packages/contracts/src/2.0.0/tokens/ZRXToken/ZRXToken.sol
index 2d8e74f2c..2e5b61e0b 100644
--- a/packages/contracts/src/contracts/current/tokens/ZRXToken/ZRXToken.sol
+++ b/packages/contracts/src/2.0.0/tokens/ZRXToken/ZRXToken.sol
@@ -18,7 +18,7 @@
 
 pragma solidity ^0.4.11;
 
-import { UnlimitedAllowanceToken_v1 as UnlimitedAllowanceToken } from "../../../previous/UnlimitedAllowanceToken/UnlimitedAllowanceToken_v1.sol";
+import { UnlimitedAllowanceToken_v1 as UnlimitedAllowanceToken } from "../../../1.0.0/UnlimitedAllowanceToken/UnlimitedAllowanceToken_v1.sol";
 
 contract ZRXToken is UnlimitedAllowanceToken {
 
diff --git a/packages/contracts/src/contracts/current/utils/LibBytes/LibBytes.sol b/packages/contracts/src/2.0.0/utils/LibBytes/LibBytes.sol
index e4cbf318b..78b1ddf7c 100644
--- a/packages/contracts/src/contracts/current/utils/LibBytes/LibBytes.sol
+++ b/packages/contracts/src/2.0.0/utils/LibBytes/LibBytes.sol
@@ -19,17 +19,8 @@
 pragma solidity ^0.4.24;
 
 library LibBytes {
-    using LibBytes for bytes;
 
-    // Revert reasons
-    string constant GREATER_THAN_ZERO_LENGTH_REQUIRED = "GREATER_THAN_ZERO_LENGTH_REQUIRED";
-    string constant GREATER_OR_EQUAL_TO_4_LENGTH_REQUIRED = "GREATER_OR_EQUAL_TO_4_LENGTH_REQUIRED";
-    string constant GREATER_OR_EQUAL_TO_20_LENGTH_REQUIRED = "GREATER_OR_EQUAL_TO_20_LENGTH_REQUIRED";
-    string constant GREATER_OR_EQUAL_TO_32_LENGTH_REQUIRED = "GREATER_OR_EQUAL_TO_32_LENGTH_REQUIRED";
-    string constant GREATER_OR_EQUAL_TO_NESTED_BYTES_LENGTH_REQUIRED = "GREATER_OR_EQUAL_TO_NESTED_BYTES_LENGTH_REQUIRED";
-    string constant GREATER_OR_EQUAL_TO_SOURCE_BYTES_LENGTH_REQUIRED = "GREATER_OR_EQUAL_TO_SOURCE_BYTES_LENGTH_REQUIRED";
-    string constant FROM_LESS_THAN_TO_REQUIRED = "FROM_LESS_THAN_TO_REQUIRED";
-    string constant TO_LESS_THAN_LENGTH_REQUIRED = "TO_LESS_THAN_LENGTH_REQUIRED";
+    using LibBytes for bytes;
 
     /// @dev Gets the memory address for a byte array.
     /// @param input Byte array to lookup.
@@ -176,8 +167,14 @@ library LibBytes {
         pure
         returns (bytes memory result)
     {
-        require(from <= to, FROM_LESS_THAN_TO_REQUIRED);
-        require(to < b.length, TO_LESS_THAN_LENGTH_REQUIRED);
+        require(
+            from <= to,
+            "FROM_LESS_THAN_TO_REQUIRED"
+        );
+        require(
+            to < b.length,
+            "TO_LESS_THAN_LENGTH_REQUIRED"
+        );
         
         // Create a new bytes structure and copy contents
         result = new bytes(to - from);
@@ -199,8 +196,14 @@ library LibBytes {
         pure
         returns (bytes memory result)
     {
-        require(from <= to, FROM_LESS_THAN_TO_REQUIRED);
-        require(to < b.length, TO_LESS_THAN_LENGTH_REQUIRED);
+        require(
+            from <= to,
+            "FROM_LESS_THAN_TO_REQUIRED"
+        );
+        require(
+            to < b.length,
+            "TO_LESS_THAN_LENGTH_REQUIRED"
+        );
         
         // Create a new bytes structure around [from, to) in-place.
         assembly {
@@ -220,7 +223,7 @@ library LibBytes {
     {
         require(
             b.length > 0,
-            GREATER_THAN_ZERO_LENGTH_REQUIRED
+            "GREATER_THAN_ZERO_LENGTH_REQUIRED"
         );
 
         // Store last byte.
@@ -244,7 +247,7 @@ library LibBytes {
     {
         require(
             b.length >= 20,
-            GREATER_OR_EQUAL_TO_20_LENGTH_REQUIRED
+            "GREATER_OR_EQUAL_TO_20_LENGTH_REQUIRED"
         );
 
         // Store last 20 bytes.
@@ -290,7 +293,7 @@ library LibBytes {
     {
         require(
             b.length >= index + 20,  // 20 is length of address
-            GREATER_OR_EQUAL_TO_20_LENGTH_REQUIRED
+            "GREATER_OR_EQUAL_TO_20_LENGTH_REQUIRED"
         );
 
         // Add offset to index:
@@ -322,7 +325,7 @@ library LibBytes {
     {
         require(
             b.length >= index + 20,  // 20 is length of address
-            GREATER_OR_EQUAL_TO_20_LENGTH_REQUIRED
+            "GREATER_OR_EQUAL_TO_20_LENGTH_REQUIRED"
         );
 
         // Add offset to index:
@@ -365,7 +368,7 @@ library LibBytes {
     {
         require(
             b.length >= index + 32,
-            GREATER_OR_EQUAL_TO_32_LENGTH_REQUIRED
+            "GREATER_OR_EQUAL_TO_32_LENGTH_REQUIRED"
         );
 
         // Arrays are prefixed by a 256 bit length parameter
@@ -392,7 +395,7 @@ library LibBytes {
     {
         require(
             b.length >= index + 32,
-            GREATER_OR_EQUAL_TO_32_LENGTH_REQUIRED
+            "GREATER_OR_EQUAL_TO_32_LENGTH_REQUIRED"
         );
 
         // Arrays are prefixed by a 256 bit length parameter
@@ -447,7 +450,7 @@ library LibBytes {
     {
         require(
             b.length >= index + 4,
-            GREATER_OR_EQUAL_TO_4_LENGTH_REQUIRED
+            "GREATER_OR_EQUAL_TO_4_LENGTH_REQUIRED"
         );
         assembly {
             result := mload(add(b, 32))
@@ -459,6 +462,8 @@ library LibBytes {
     }
 
     /// @dev Reads nested bytes from a specific position.
+    /// @dev NOTE: the returned value overlaps with the input value.
+    ///            Both should be treated as immutable.
     /// @param b Byte array containing nested bytes.
     /// @param index Index of nested bytes.
     /// @return result Nested bytes.
@@ -478,17 +483,13 @@ library LibBytes {
         // length of nested bytes
         require(
             b.length >= index + nestedBytesLength,
-            GREATER_OR_EQUAL_TO_NESTED_BYTES_LENGTH_REQUIRED
+            "GREATER_OR_EQUAL_TO_NESTED_BYTES_LENGTH_REQUIRED"
         );
-
-        // Allocate memory and copy value to result
-        result = new bytes(nestedBytesLength);
-        memCopy(
-            result.contentAddress(),
-            b.contentAddress() + index,
-            nestedBytesLength
-        );
-
+        
+        // Return a pointer to the byte array as it exists inside `b`
+        assembly {
+            result := add(b, index)
+        }
         return result;
     }
 
@@ -508,7 +509,7 @@ library LibBytes {
         // length of input
         require(
             b.length >= index + 32 /* 32 bytes to store length */ + input.length,
-            GREATER_OR_EQUAL_TO_NESTED_BYTES_LENGTH_REQUIRED
+            "GREATER_OR_EQUAL_TO_NESTED_BYTES_LENGTH_REQUIRED"
         );
 
         // Copy <input> into <b>
@@ -533,7 +534,7 @@ library LibBytes {
         // Dest length must be >= source length, or some bytes would not be copied.
         require(
             dest.length >= sourceLen,
-            GREATER_OR_EQUAL_TO_SOURCE_BYTES_LENGTH_REQUIRED
+            "GREATER_OR_EQUAL_TO_SOURCE_BYTES_LENGTH_REQUIRED"
         );
         memCopy(
             dest.contentAddress(),
diff --git a/packages/contracts/src/contracts/current/utils/Ownable/IOwnable.sol b/packages/contracts/src/2.0.0/utils/Ownable/IOwnable.sol
index e77680903..e77680903 100644
--- a/packages/contracts/src/contracts/current/utils/Ownable/IOwnable.sol
+++ b/packages/contracts/src/2.0.0/utils/Ownable/IOwnable.sol
diff --git a/packages/contracts/src/contracts/current/utils/Ownable/Ownable.sol b/packages/contracts/src/2.0.0/utils/Ownable/Ownable.sol
index 99b93d0d2..6f5761cc7 100644
--- a/packages/contracts/src/contracts/current/utils/Ownable/Ownable.sol
+++ b/packages/contracts/src/2.0.0/utils/Ownable/Ownable.sol
@@ -13,9 +13,6 @@ import "./IOwnable.sol";
 contract Ownable is IOwnable {
     address public owner;
 
-    // Revert reasons
-    string constant ONLY_CONTRACT_OWNER = "ONLY_CONTRACT_OWNER";
-
     constructor ()
         public
     {
@@ -25,7 +22,7 @@ contract Ownable is IOwnable {
     modifier onlyOwner() {
         require(
             msg.sender == owner,
-            ONLY_CONTRACT_OWNER
+            "ONLY_CONTRACT_OWNER"
         );
         _;
     }
diff --git a/packages/contracts/src/contracts/current/utils/SafeMath/SafeMath.sol b/packages/contracts/src/2.0.0/utils/SafeMath/SafeMath.sol
index e137f6ca5..e137f6ca5 100644
--- a/packages/contracts/src/contracts/current/utils/SafeMath/SafeMath.sol
+++ b/packages/contracts/src/2.0.0/utils/SafeMath/SafeMath.sol
diff --git a/packages/contracts/src/contracts/current/protocol/AssetProxy/ERC20Proxy.sol b/packages/contracts/src/contracts/current/protocol/AssetProxy/ERC20Proxy.sol
deleted file mode 100644
index 7ca823d1f..000000000
--- a/packages/contracts/src/contracts/current/protocol/AssetProxy/ERC20Proxy.sol
+++ /dev/null
@@ -1,44 +0,0 @@
-/*
-
-  Copyright 2018 ZeroEx Intl.
-
-  Licensed under the Apache License, Version 2.0 (the "License");
-  you may not use this file except in compliance with the License.
-  You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-  Unless required by applicable law or agreed to in writing, software
-  distributed under the License is distributed on an "AS IS" BASIS,
-  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-  See the License for the specific language governing permissions and
-  limitations under the License.
-
-*/
-
-pragma solidity ^0.4.24;
-pragma experimental ABIEncoderV2;
-
-import "../../utils/LibBytes/LibBytes.sol";
-import "./MixinAssetProxy.sol";
-import "./MixinAuthorizable.sol";
-import "./MixinERC20Transfer.sol";
-
-contract ERC20Proxy is
-    MixinAssetProxy,
-    MixinAuthorizable,
-    MixinERC20Transfer
-{
-    // Id of this proxy.
-    uint8 constant PROXY_ID = 1;
-
-    /// @dev Gets the proxy id associated with the proxy address.
-    /// @return Proxy id.
-    function getProxyId()
-        external
-        view
-        returns (uint8)
-    {
-        return PROXY_ID;
-    }
-}
diff --git a/packages/contracts/src/contracts/current/protocol/AssetProxy/ERC721Proxy.sol b/packages/contracts/src/contracts/current/protocol/AssetProxy/ERC721Proxy.sol
deleted file mode 100644
index 7ff25aea3..000000000
--- a/packages/contracts/src/contracts/current/protocol/AssetProxy/ERC721Proxy.sol
+++ /dev/null
@@ -1,44 +0,0 @@
-/*
-
-  Copyright 2018 ZeroEx Intl.
-
-  Licensed under the Apache License, Version 2.0 (the "License");
-  you may not use this file except in compliance with the License.
-  You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-  Unless required by applicable law or agreed to in writing, software
-  distributed under the License is distributed on an "AS IS" BASIS,
-  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-  See the License for the specific language governing permissions and
-  limitations under the License.
-
-*/
-
-pragma solidity ^0.4.24;
-pragma experimental ABIEncoderV2;
-
-import "../../utils/LibBytes/LibBytes.sol";
-import "./MixinAssetProxy.sol";
-import "./MixinAuthorizable.sol";
-import "./MixinERC721Transfer.sol";
-
-contract ERC721Proxy is
-    MixinAssetProxy,
-    MixinAuthorizable,
-    MixinERC721Transfer
-{
-    // Id of this proxy.
-    uint8 constant PROXY_ID = 2;
-
-    /// @dev Gets the proxy id associated with the proxy address.
-    /// @return Proxy id.
-    function getProxyId()
-        external
-        view
-        returns (uint8)
-    {
-        return PROXY_ID;
-    }
-}
diff --git a/packages/contracts/src/contracts/current/protocol/AssetProxy/MixinAssetProxy.sol b/packages/contracts/src/contracts/current/protocol/AssetProxy/MixinAssetProxy.sol
deleted file mode 100644
index 9032658e7..000000000
--- a/packages/contracts/src/contracts/current/protocol/AssetProxy/MixinAssetProxy.sol
+++ /dev/null
@@ -1,75 +0,0 @@
-/*
-
-  Copyright 2018 ZeroEx Intl.
-
-  Licensed under the Apache License, Version 2.0 (the "License");
-  you may not use this file except in compliance with the License.
-  You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-  Unless required by applicable law or agreed to in writing, software
-  distributed under the License is distributed on an "AS IS" BASIS,
-  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-  See the License for the specific language governing permissions and
-  limitations under the License.
-
-*/
-
-pragma solidity ^0.4.24;
-pragma experimental ABIEncoderV2;
-
-import "./mixins/MAuthorizable.sol";
-import "./mixins/MAssetProxy.sol";
-
-contract MixinAssetProxy is
-    MAuthorizable,
-    MAssetProxy
-{
-
-    /// @dev Transfers assets. Either succeeds or throws.
-    /// @param assetData Encoded byte array.
-    /// @param from Address to transfer asset from.
-    /// @param to Address to transfer asset to.
-    /// @param amount Amount of asset to transfer.
-    function transferFrom(
-        bytes assetData,
-        address from,
-        address to,
-        uint256 amount
-    )
-        external
-        onlyAuthorized
-    {
-        transferFromInternal(
-            assetData,
-            from,
-            to,
-            amount
-        );
-    }
-
-    /// @dev Makes multiple transfers of assets. Either succeeds or throws.
-    /// @param assetData Array of byte arrays encoded for the respective asset proxy.
-    /// @param from Array of addresses to transfer assets from.
-    /// @param to Array of addresses to transfer assets to.
-    /// @param amounts Array of amounts of assets to transfer.
-    function batchTransferFrom(
-        bytes[] memory assetData,
-        address[] memory from,
-        address[] memory to,
-        uint256[] memory amounts
-    )
-        public
-        onlyAuthorized
-    {
-        for (uint256 i = 0; i < assetData.length; i++) {
-            transferFromInternal(
-                assetData[i],
-                from[i],
-                to[i],
-                amounts[i]
-            );
-        }
-    }
-}
diff --git a/packages/contracts/src/contracts/current/protocol/AssetProxy/MixinERC20Transfer.sol b/packages/contracts/src/contracts/current/protocol/AssetProxy/MixinERC20Transfer.sol
deleted file mode 100644
index 0e7f3fc89..000000000
--- a/packages/contracts/src/contracts/current/protocol/AssetProxy/MixinERC20Transfer.sol
+++ /dev/null
@@ -1,82 +0,0 @@
-/*
-
-  Copyright 2018 ZeroEx Intl.
-
-  Licensed under the Apache License, Version 2.0 (the "License");
-  you may not use this file except in compliance with the License.
-  You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-  Unless required by applicable law or agreed to in writing, software
-  distributed under the License is distributed on an "AS IS" BASIS,
-  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-  See the License for the specific language governing permissions and
-  limitations under the License.
-
-*/
-
-pragma solidity ^0.4.24;
-pragma experimental ABIEncoderV2;
-
-import "../../utils/LibBytes/LibBytes.sol";
-import "../../tokens/ERC20Token/IERC20Token.sol";
-import "./libs/LibTransferErrors.sol";
-
-contract MixinERC20Transfer is
-    LibTransferErrors
-{
-    using LibBytes for bytes;
-
-    /// @dev Internal version of `transferFrom`.
-    /// @param assetData Encoded byte array.
-    /// @param from Address to transfer asset from.
-    /// @param to Address to transfer asset to.
-    /// @param amount Amount of asset to transfer.
-    function transferFromInternal(
-        bytes memory assetData,
-        address from,
-        address to,
-        uint256 amount
-    )
-        internal
-    {
-        // Decode asset data.
-        address token = assetData.readAddress(0);
-
-        // Transfer tokens.
-        // We do a raw call so we can check the success separate
-        // from the return data.
-        bool success = token.call(abi.encodeWithSelector(
-            IERC20Token(token).transferFrom.selector,
-            from,
-            to,
-            amount
-        ));
-        require(
-            success,
-            TRANSFER_FAILED
-        );
-        
-        // Check return data.
-        // If there is no return data, we assume the token incorrectly
-        // does not return a bool. In this case we expect it to revert
-        // on failure, which was handled above.
-        // If the token does return data, we require that it is a single
-        // value that evaluates to true.
-        assembly {
-            if returndatasize {
-                success := 0
-                if eq(returndatasize, 32) {
-                    // First 64 bytes of memory are reserved scratch space
-                    returndatacopy(0, 0, 32)
-                    success := mload(0)
-                }
-            }
-        }
-        require(
-            success,
-            TRANSFER_FAILED
-        );
-    }
-}
diff --git a/packages/contracts/src/contracts/current/protocol/AssetProxy/MixinERC721Transfer.sol b/packages/contracts/src/contracts/current/protocol/AssetProxy/MixinERC721Transfer.sol
deleted file mode 100644
index 944068bbb..000000000
--- a/packages/contracts/src/contracts/current/protocol/AssetProxy/MixinERC721Transfer.sol
+++ /dev/null
@@ -1,94 +0,0 @@
-/*
-
-  Copyright 2018 ZeroEx Intl.
-
-  Licensed under the Apache License, Version 2.0 (the "License");
-  you may not use this file except in compliance with the License.
-  You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-  Unless required by applicable law or agreed to in writing, software
-  distributed under the License is distributed on an "AS IS" BASIS,
-  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-  See the License for the specific language governing permissions and
-  limitations under the License.
-
-*/
-
-pragma solidity ^0.4.24;
-pragma experimental ABIEncoderV2;
-
-import "../../utils/LibBytes/LibBytes.sol";
-import "../../tokens/ERC721Token/ERC721Token.sol";
-import "./libs/LibTransferErrors.sol";
-
-contract MixinERC721Transfer is
-    LibTransferErrors
-{
-    using LibBytes for bytes;
-    
-    /// @dev Internal version of `transferFrom`.
-    /// @param assetData Encoded byte array.
-    /// @param from Address to transfer asset from.
-    /// @param to Address to transfer asset to.
-    /// @param amount Amount of asset to transfer.
-    function transferFromInternal(
-        bytes memory assetData,
-        address from,
-        address to,
-        uint256 amount
-    )
-        internal
-    {
-        // There exists only 1 of each token.
-        require(
-            amount == 1,
-            INVALID_AMOUNT
-        );
-    
-        // Decode asset data.
-        (
-            address token,
-            uint256 tokenId,
-            bytes memory receiverData
-        ) = decodeERC721AssetData(assetData);
-
-        ERC721Token(token).safeTransferFrom(
-            from,
-            to,
-            tokenId,
-            receiverData
-        );
-    }
-
-    /// @dev Decodes ERC721 Asset data.
-    /// @param assetData Encoded byte array.
-    /// @return proxyId Intended ERC721 proxy id.
-    /// @return token ERC721 token address.
-    /// @return tokenId ERC721 token id.
-    /// @return receiverData Additional data with no specific format, which
-    ///                      is passed to the receiving contract's onERC721Received.
-    function decodeERC721AssetData(bytes memory assetData)
-        internal
-        pure
-        returns (
-            address token,
-            uint256 tokenId,
-            bytes memory receiverData
-        )
-    {
-        // Decode asset data.
-        token = assetData.readAddress(0);
-        tokenId = assetData.readUint256(20);
-        if (assetData.length > 52) {
-            receiverData = assetData.readBytesWithLength(52);
-        }
-
-        return (
-            token,
-            tokenId,
-            receiverData
-        );
-    }
-}
diff --git a/packages/contracts/src/contracts/current/protocol/AssetProxy/mixins/MAssetProxy.sol b/packages/contracts/src/contracts/current/protocol/AssetProxy/mixins/MAssetProxy.sol
deleted file mode 100644
index a52cb56f9..000000000
--- a/packages/contracts/src/contracts/current/protocol/AssetProxy/mixins/MAssetProxy.sol
+++ /dev/null
@@ -1,40 +0,0 @@
-/*
-
-  Copyright 2018 ZeroEx Intl.
-
-  Licensed under the Apache License, Version 2.0 (the "License");
-  you may not use this file except in compliance with the License.
-  You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-  Unless required by applicable law or agreed to in writing, software
-  distributed under the License is distributed on an "AS IS" BASIS,
-  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-  See the License for the specific language governing permissions and
-  limitations under the License.
-
-*/
-
-pragma solidity ^0.4.24;
-pragma experimental ABIEncoderV2;
-
-import "../interfaces/IAssetProxy.sol";
-
-contract MAssetProxy is
-    IAssetProxy
-{
-
-    /// @dev Internal version of `transferFrom`.
-    /// @param assetData Encoded byte array.
-    /// @param from Address to transfer asset from.
-    /// @param to Address to transfer asset to.
-    /// @param amount Amount of asset to transfer.
-    function transferFromInternal(
-        bytes memory assetData,
-        address from,
-        address to,
-        uint256 amount
-    )
-        internal;
-}
diff --git a/packages/contracts/src/contracts/current/protocol/Exchange/MixinAssetProxyDispatcher.sol b/packages/contracts/src/contracts/current/protocol/Exchange/MixinAssetProxyDispatcher.sol
deleted file mode 100644
index b8d6c0722..000000000
--- a/packages/contracts/src/contracts/current/protocol/Exchange/MixinAssetProxyDispatcher.sol
+++ /dev/null
@@ -1,118 +0,0 @@
-/*
-
-  Copyright 2018 ZeroEx Intl.
-
-  Licensed under the Apache License, Version 2.0 (the "License");
-  you may not use this file except in compliance with the License.
-  You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-  Unless required by applicable law or agreed to in writing, software
-  distributed under the License is distributed on an "AS IS" BASIS,
-  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-  See the License for the specific language governing permissions and
-  limitations under the License.
-
-*/
-
-pragma solidity ^0.4.24;
-
-import "../../utils/Ownable/Ownable.sol";
-import "./libs/LibExchangeErrors.sol";
-import "./mixins/MAssetProxyDispatcher.sol";
-import "../AssetProxy/interfaces/IAssetProxy.sol";
-
-contract MixinAssetProxyDispatcher is
-    Ownable,
-    LibExchangeErrors,
-    MAssetProxyDispatcher
-{
-    // Mapping from Asset Proxy Id's to their respective Asset Proxy
-    mapping (uint8 => IAssetProxy) public assetProxies;
-
-    /// @dev Registers an asset proxy to an asset proxy id.
-    ///      An id can only be assigned to a single proxy at a given time.
-    /// @param assetProxyId Id to register`newAssetProxy` under.
-    /// @param newAssetProxy Address of new asset proxy to register, or 0x0 to unset assetProxyId.
-    /// @param oldAssetProxy Existing asset proxy to overwrite, or 0x0 if assetProxyId is currently unused.
-    function registerAssetProxy(
-        uint8 assetProxyId,
-        address newAssetProxy,
-        address oldAssetProxy
-    )
-        external
-        onlyOwner
-    {
-        // Ensure the existing asset proxy is not unintentionally overwritten
-        address currentAssetProxy = assetProxies[assetProxyId];
-        require(
-            oldAssetProxy == currentAssetProxy,
-            ASSET_PROXY_MISMATCH
-        );
-
-        IAssetProxy assetProxy = IAssetProxy(newAssetProxy);
-
-        // Ensure that the id of newAssetProxy matches the passed in assetProxyId, unless it is being reset to 0.
-        if (newAssetProxy != address(0)) {
-            uint8 newAssetProxyId = assetProxy.getProxyId();
-            require(
-                newAssetProxyId == assetProxyId,
-                ASSET_PROXY_ID_MISMATCH
-            );
-        }
-
-        // Add asset proxy and log registration.
-        assetProxies[assetProxyId] = assetProxy;
-        emit AssetProxySet(
-            assetProxyId,
-            newAssetProxy,
-            oldAssetProxy
-        );
-    }
-
-    /// @dev Gets an asset proxy.
-    /// @param assetProxyId Id of the asset proxy.
-    /// @return The asset proxy registered to assetProxyId. Returns 0x0 if no proxy is registered.
-    function getAssetProxy(uint8 assetProxyId)
-        external
-        view
-        returns (address)
-    {
-        return assetProxies[assetProxyId];
-    }
-
-    /// @dev Forwards arguments to assetProxy and calls `transferFrom`. Either succeeds or throws.
-    /// @param assetData Byte array encoded for the respective asset proxy.
-    /// @param assetProxyId Id of assetProxy to dispach to.
-    /// @param from Address to transfer token from.
-    /// @param to Address to transfer token to.
-    /// @param amount Amount of token to transfer.
-    function dispatchTransferFrom(
-        bytes memory assetData,
-        uint8 assetProxyId,
-        address from,
-        address to,
-        uint256 amount
-    )
-        internal
-    {
-        // Do nothing if no amount should be transferred.
-        if (amount > 0) {
-            // Lookup assetProxy
-            IAssetProxy assetProxy = assetProxies[assetProxyId];
-            // Ensure that assetProxy exists
-            require(
-                assetProxy != address(0),
-                ASSET_PROXY_DOES_NOT_EXIST
-            );
-            // transferFrom will either succeed or throw.
-            assetProxy.transferFrom(
-                assetData,
-                from,
-                to,
-                amount
-            );
-        }
-    }
-}
diff --git a/packages/contracts/src/contracts/current/test/TestAssetDataDecoders/TestAssetDataDecoders.sol b/packages/contracts/src/contracts/current/test/TestAssetDataDecoders/TestAssetDataDecoders.sol
deleted file mode 100644
index 5987291d2..000000000
--- a/packages/contracts/src/contracts/current/test/TestAssetDataDecoders/TestAssetDataDecoders.sol
+++ /dev/null
@@ -1,56 +0,0 @@
-/*
-
-  Copyright 2018 ZeroEx Intl.
-
-  Licensed under the Apache License, Version 2.0 (the "License");
-  you may not use this file except in compliance with the License.
-  You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-  Unless required by applicable law or agreed to in writing, software
-  distributed under the License is distributed on an "AS IS" BASIS,
-  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-  See the License for the specific language governing permissions and
-  limitations under the License.
-
-*/
-
-pragma solidity ^0.4.24;
-pragma experimental ABIEncoderV2;
-
-import "../../protocol/AssetProxy/ERC20Proxy.sol";
-import "../../protocol/AssetProxy/ERC721Proxy.sol";
-
-contract TestAssetDataDecoders is
-    ERC721Proxy
-{
-    /// @dev Decodes ERC721 Asset data.
-    /// @param assetData Encoded byte array.
-    /// @return proxyId Intended ERC721 proxy id.
-    /// @return token ERC721 token address.
-    /// @return tokenId ERC721 token id.
-    /// @return receiverData Additional data with no specific format, which
-    ///                      is passed to the receiving contract's onERC721Received.
-    function publicDecodeERC721Data(bytes memory assetData)
-        public
-        pure
-        returns (
-            address token,
-            uint256 tokenId,
-            bytes memory receiverData
-        )
-    {
-        (
-            token,
-            tokenId,
-            receiverData
-        ) = decodeERC721AssetData(assetData);
-
-        return (
-            token,
-            tokenId,
-            receiverData
-        );
-    }
-}
diff --git a/packages/contracts/src/utils/artifacts.ts b/packages/contracts/src/utils/artifacts.ts
deleted file mode 100644
index a46bab9ae..000000000
--- a/packages/contracts/src/utils/artifacts.ts
+++ /dev/null
@@ -1,51 +0,0 @@
-import { ContractArtifact } from '@0xproject/sol-compiler';
-
-import * as AssetProxyOwner from '../artifacts/AssetProxyOwner.json';
-import * as DummyERC20Token from '../artifacts/DummyERC20Token.json';
-import * as DummyERC721Receiver from '../artifacts/DummyERC721Receiver.json';
-import * as DummyERC721Token from '../artifacts/DummyERC721Token.json';
-import * as ERC20Proxy from '../artifacts/ERC20Proxy.json';
-import * as ERC721Proxy from '../artifacts/ERC721Proxy.json';
-import * as Exchange from '../artifacts/Exchange.json';
-import * as ExchangeWrapper from '../artifacts/ExchangeWrapper.json';
-import * as MixinAuthorizable from '../artifacts/MixinAuthorizable.json';
-import * as MultiSigWallet from '../artifacts/MultiSigWallet.json';
-import * as MultiSigWalletWithTimeLock from '../artifacts/MultiSigWalletWithTimeLock.json';
-import * as TestAssetDataDecoders from '../artifacts/TestAssetDataDecoders.json';
-import * as TestAssetProxyDispatcher from '../artifacts/TestAssetProxyDispatcher.json';
-import * as TestAssetProxyOwner from '../artifacts/TestAssetProxyOwner.json';
-import * as TestLibBytes from '../artifacts/TestLibBytes.json';
-import * as TestLibs from '../artifacts/TestLibs.json';
-import * as TestSignatureValidator from '../artifacts/TestSignatureValidator.json';
-import * as TestValidator from '../artifacts/TestValidator.json';
-import * as TestWallet from '../artifacts/TestWallet.json';
-import * as TokenRegistry from '../artifacts/TokenRegistry.json';
-import * as EtherToken from '../artifacts/WETH9.json';
-import * as Whitelist from '../artifacts/Whitelist.json';
-import * as ZRX from '../artifacts/ZRXToken.json';
-
-export const artifacts = {
-    AssetProxyOwner: (AssetProxyOwner as any) as ContractArtifact,
-    DummyERC20Token: (DummyERC20Token as any) as ContractArtifact,
-    DummyERC721Receiver: (DummyERC721Receiver as any) as ContractArtifact,
-    DummyERC721Token: (DummyERC721Token as any) as ContractArtifact,
-    ERC20Proxy: (ERC20Proxy as any) as ContractArtifact,
-    ERC721Proxy: (ERC721Proxy as any) as ContractArtifact,
-    Exchange: (Exchange as any) as ContractArtifact,
-    ExchangeWrapper: (ExchangeWrapper as any) as ContractArtifact,
-    EtherToken: (EtherToken as any) as ContractArtifact,
-    MixinAuthorizable: (MixinAuthorizable as any) as ContractArtifact,
-    MultiSigWallet: (MultiSigWallet as any) as ContractArtifact,
-    MultiSigWalletWithTimeLock: (MultiSigWalletWithTimeLock as any) as ContractArtifact,
-    TestAssetProxyOwner: (TestAssetProxyOwner as any) as ContractArtifact,
-    TestAssetProxyDispatcher: (TestAssetProxyDispatcher as any) as ContractArtifact,
-    TestAssetDataDecoders: (TestAssetDataDecoders as any) as ContractArtifact,
-    TestLibBytes: (TestLibBytes as any) as ContractArtifact,
-    TestLibs: (TestLibs as any) as ContractArtifact,
-    TestSignatureValidator: (TestSignatureValidator as any) as ContractArtifact,
-    TestValidator: (TestValidator as any) as ContractArtifact,
-    TestWallet: (TestWallet as any) as ContractArtifact,
-    TokenRegistry: (TokenRegistry as any) as ContractArtifact,
-    Whitelist: (Whitelist as any) as ContractArtifact,
-    ZRX: (ZRX as any) as ContractArtifact,
-};
diff --git a/packages/contracts/test/asset_proxy/authorizable.ts b/packages/contracts/test/asset_proxy/authorizable.ts
index c35dc7882..5a0586c28 100644
--- a/packages/contracts/test/asset_proxy/authorizable.ts
+++ b/packages/contracts/test/asset_proxy/authorizable.ts
@@ -1,13 +1,14 @@
 import { BlockchainLifecycle } from '@0xproject/dev-utils';
+import { RevertReason } from '@0xproject/types';
 import { BigNumber } from '@0xproject/utils';
 import * as chai from 'chai';
 
-import { MixinAuthorizableContract } from '../../src/generated_contract_wrappers/mixin_authorizable';
-import { artifacts } from '../../src/utils/artifacts';
-import { expectRevertOrAlwaysFailingTransactionAsync } from '../../src/utils/assertions';
-import { chaiSetup } from '../../src/utils/chai_setup';
-import { constants } from '../../src/utils/constants';
-import { provider, txDefaults, web3Wrapper } from '../../src/utils/web3_wrapper';
+import { MixinAuthorizableContract } from '../../generated_contract_wrappers/mixin_authorizable';
+import { artifacts } from '../utils/artifacts';
+import { expectRevertReasonOrAlwaysFailingTransactionAsync } from '../utils/assertions';
+import { chaiSetup } from '../utils/chai_setup';
+import { constants } from '../utils/constants';
+import { provider, txDefaults, web3Wrapper } from '../utils/web3_wrapper';
 
 chaiSetup.configure();
 const expect = chai.expect;
@@ -43,8 +44,9 @@ describe('Authorizable', () => {
     });
     describe('addAuthorizedAddress', () => {
         it('should throw if not called by owner', async () => {
-            return expectRevertOrAlwaysFailingTransactionAsync(
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
                 authorizable.addAuthorizedAddress.sendTransactionAsync(notOwner, { from: notOwner }),
+                RevertReason.OnlyContractOwner,
             );
         });
         it('should allow owner to add an authorized address', async () => {
@@ -60,8 +62,9 @@ describe('Authorizable', () => {
                 await authorizable.addAuthorizedAddress.sendTransactionAsync(address, { from: owner }),
                 constants.AWAIT_TRANSACTION_MINED_MS,
             );
-            return expectRevertOrAlwaysFailingTransactionAsync(
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
                 authorizable.addAuthorizedAddress.sendTransactionAsync(address, { from: owner }),
+                RevertReason.TargetAlreadyAuthorized,
             );
         });
     });
@@ -72,10 +75,11 @@ describe('Authorizable', () => {
                 await authorizable.addAuthorizedAddress.sendTransactionAsync(address, { from: owner }),
                 constants.AWAIT_TRANSACTION_MINED_MS,
             );
-            return expectRevertOrAlwaysFailingTransactionAsync(
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
                 authorizable.removeAuthorizedAddress.sendTransactionAsync(address, {
                     from: notOwner,
                 }),
+                RevertReason.OnlyContractOwner,
             );
         });
 
@@ -95,10 +99,11 @@ describe('Authorizable', () => {
         });
 
         it('should throw if owner attempts to remove an address that is not authorized', async () => {
-            return expectRevertOrAlwaysFailingTransactionAsync(
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
                 authorizable.removeAuthorizedAddress.sendTransactionAsync(address, {
                     from: owner,
                 }),
+                RevertReason.TargetNotAuthorized,
             );
         });
     });
@@ -110,10 +115,11 @@ describe('Authorizable', () => {
                 constants.AWAIT_TRANSACTION_MINED_MS,
             );
             const index = new BigNumber(0);
-            return expectRevertOrAlwaysFailingTransactionAsync(
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
                 authorizable.removeAuthorizedAddressAtIndex.sendTransactionAsync(address, index, {
                     from: notOwner,
                 }),
+                RevertReason.OnlyContractOwner,
             );
         });
         it('should throw if index is >= authorities.length', async () => {
@@ -122,18 +128,20 @@ describe('Authorizable', () => {
                 constants.AWAIT_TRANSACTION_MINED_MS,
             );
             const index = new BigNumber(1);
-            return expectRevertOrAlwaysFailingTransactionAsync(
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
                 authorizable.removeAuthorizedAddressAtIndex.sendTransactionAsync(address, index, {
                     from: owner,
                 }),
+                RevertReason.IndexOutOfBounds,
             );
         });
         it('should throw if owner attempts to remove an address that is not authorized', async () => {
             const index = new BigNumber(0);
-            return expectRevertOrAlwaysFailingTransactionAsync(
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
                 authorizable.removeAuthorizedAddressAtIndex.sendTransactionAsync(address, index, {
                     from: owner,
                 }),
+                RevertReason.TargetNotAuthorized,
             );
         });
         it('should throw if address at index does not match target', async () => {
@@ -148,10 +156,11 @@ describe('Authorizable', () => {
                 constants.AWAIT_TRANSACTION_MINED_MS,
             );
             const address1Index = new BigNumber(0);
-            return expectRevertOrAlwaysFailingTransactionAsync(
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
                 authorizable.removeAuthorizedAddressAtIndex.sendTransactionAsync(address2, address1Index, {
                     from: owner,
                 }),
+                RevertReason.AuthorizedAddressMismatch,
             );
         });
         it('should allow owner to remove an authorized address', async () => {
diff --git a/packages/contracts/test/asset_proxy/decoder.ts b/packages/contracts/test/asset_proxy/decoder.ts
deleted file mode 100644
index 98d18aa38..000000000
--- a/packages/contracts/test/asset_proxy/decoder.ts
+++ /dev/null
@@ -1,85 +0,0 @@
-import { BlockchainLifecycle } from '@0xproject/dev-utils';
-import { assetProxyUtils, generatePseudoRandomSalt } from '@0xproject/order-utils';
-import { BigNumber } from '@0xproject/utils';
-import * as chai from 'chai';
-import ethUtil = require('ethereumjs-util');
-
-import { TestAssetDataDecodersContract } from '../../src/generated_contract_wrappers/test_asset_data_decoders';
-import { artifacts } from '../../src/utils/artifacts';
-import { chaiSetup } from '../../src/utils/chai_setup';
-import { provider, txDefaults, web3Wrapper } from '../../src/utils/web3_wrapper';
-
-chaiSetup.configure();
-const expect = chai.expect;
-const blockchainLifecycle = new BlockchainLifecycle(web3Wrapper);
-
-describe('TestAssetDataDecoders', () => {
-    let testAssetProxyDecoder: TestAssetDataDecodersContract;
-    let testAddress: string;
-
-    before(async () => {
-        await blockchainLifecycle.startAsync();
-    });
-    after(async () => {
-        await blockchainLifecycle.revertAsync();
-    });
-    before(async () => {
-        // Setup accounts & addresses
-        const accounts = await web3Wrapper.getAvailableAddressesAsync();
-        testAddress = accounts[0];
-        testAssetProxyDecoder = await TestAssetDataDecodersContract.deployFrom0xArtifactAsync(
-            artifacts.TestAssetDataDecoders,
-            provider,
-            txDefaults,
-        );
-    });
-    beforeEach(async () => {
-        await blockchainLifecycle.startAsync();
-    });
-    afterEach(async () => {
-        await blockchainLifecycle.revertAsync();
-    });
-
-    describe('Asset Data Decoders', () => {
-        it('should correctly decode ERC721 asset data', async () => {
-            const tokenId = generatePseudoRandomSalt();
-            const encodedAssetData = assetProxyUtils.encodeERC721AssetData(testAddress, tokenId);
-            const encodedAssetDataWithoutProxyId = encodedAssetData.slice(0, -2);
-            const expectedDecodedAssetData = assetProxyUtils.decodeERC721AssetData(encodedAssetData);
-            let decodedTokenAddress: string;
-            let decodedTokenId: BigNumber;
-            let decodedData: string;
-            [
-                decodedTokenAddress,
-                decodedTokenId,
-                decodedData,
-            ] = await testAssetProxyDecoder.publicDecodeERC721Data.callAsync(encodedAssetDataWithoutProxyId);
-            expect(decodedTokenAddress).to.be.equal(expectedDecodedAssetData.tokenAddress);
-            expect(decodedTokenId).to.be.bignumber.equal(expectedDecodedAssetData.tokenId);
-            expect(decodedData).to.be.equal(expectedDecodedAssetData.receiverData);
-        });
-
-        it('should correctly decode ERC721 asset data with receiver data', async () => {
-            const tokenId = generatePseudoRandomSalt();
-            const receiverDataFirst32Bytes = ethUtil.bufferToHex(
-                assetProxyUtils.encodeUint256(generatePseudoRandomSalt()),
-            );
-            const receiverDataExtraBytes = 'FFFF';
-            // We add extra bytes to generate a value that doesn't fit perfectly into one word
-            const receiverData = receiverDataFirst32Bytes + receiverDataExtraBytes;
-            const encodedAssetData = assetProxyUtils.encodeERC721AssetData(testAddress, tokenId, receiverData);
-            const expectedDecodedAssetData = assetProxyUtils.decodeERC721AssetData(encodedAssetData);
-            let decodedTokenAddress: string;
-            let decodedTokenId: BigNumber;
-            let decodedReceiverData: string;
-            [
-                decodedTokenAddress,
-                decodedTokenId,
-                decodedReceiverData,
-            ] = await testAssetProxyDecoder.publicDecodeERC721Data.callAsync(encodedAssetData);
-            expect(decodedTokenAddress).to.be.equal(expectedDecodedAssetData.tokenAddress);
-            expect(decodedTokenId).to.be.bignumber.equal(expectedDecodedAssetData.tokenId);
-            expect(decodedReceiverData).to.be.equal(expectedDecodedAssetData.receiverData);
-        });
-    });
-});
diff --git a/packages/contracts/test/asset_proxy/proxies.ts b/packages/contracts/test/asset_proxy/proxies.ts
index 2c27f7382..fc1e53352 100644
--- a/packages/contracts/test/asset_proxy/proxies.ts
+++ b/packages/contracts/test/asset_proxy/proxies.ts
@@ -1,31 +1,38 @@
 import { BlockchainLifecycle } from '@0xproject/dev-utils';
 import { assetProxyUtils, generatePseudoRandomSalt } from '@0xproject/order-utils';
+import { RevertReason } from '@0xproject/types';
 import { BigNumber } from '@0xproject/utils';
 import * as chai from 'chai';
 import { LogWithDecodedArgs } from 'ethereum-types';
 import ethUtil = require('ethereumjs-util');
 import * as _ from 'lodash';
 
-import { DummyERC20TokenContract } from '../../src/generated_contract_wrappers/dummy_e_r_c20_token';
+import { DummyERC20TokenContract } from '../../generated_contract_wrappers/dummy_e_r_c20_token';
 import {
     DummyERC721ReceiverContract,
     TokenReceivedContractEventArgs,
-} from '../../src/generated_contract_wrappers/dummy_e_r_c721_receiver';
-import { DummyERC721TokenContract } from '../../src/generated_contract_wrappers/dummy_e_r_c721_token';
-import { ERC20ProxyContract } from '../../src/generated_contract_wrappers/e_r_c20_proxy';
-import { ERC721ProxyContract } from '../../src/generated_contract_wrappers/e_r_c721_proxy';
-import { artifacts } from '../../src/utils/artifacts';
-import { expectRevertOrAlwaysFailingTransactionAsync } from '../../src/utils/assertions';
-import { chaiSetup } from '../../src/utils/chai_setup';
-import { constants } from '../../src/utils/constants';
-import { ERC20Wrapper } from '../../src/utils/erc20_wrapper';
-import { ERC721Wrapper } from '../../src/utils/erc721_wrapper';
-import { LogDecoder } from '../../src/utils/log_decoder';
-import { provider, txDefaults, web3Wrapper } from '../../src/utils/web3_wrapper';
+} from '../../generated_contract_wrappers/dummy_e_r_c721_receiver';
+import { DummyERC721TokenContract } from '../../generated_contract_wrappers/dummy_e_r_c721_token';
+import { ERC20ProxyContract } from '../../generated_contract_wrappers/e_r_c20_proxy';
+import { ERC721ProxyContract } from '../../generated_contract_wrappers/e_r_c721_proxy';
+import { IAssetProxyContract } from '../../generated_contract_wrappers/i_asset_proxy';
+import { artifacts } from '../utils/artifacts';
+import { expectRevertReasonOrAlwaysFailingTransactionAsync } from '../utils/assertions';
+import { chaiSetup } from '../utils/chai_setup';
+import { constants } from '../utils/constants';
+import { ERC20Wrapper } from '../utils/erc20_wrapper';
+import { ERC721Wrapper } from '../utils/erc721_wrapper';
+import { LogDecoder } from '../utils/log_decoder';
+import { provider, txDefaults, web3Wrapper } from '../utils/web3_wrapper';
 
 chaiSetup.configure();
 const expect = chai.expect;
 const blockchainLifecycle = new BlockchainLifecycle(web3Wrapper);
+const assetProxyInterface = new IAssetProxyContract(
+    artifacts.IAssetProxy.compilerOutput.abi,
+    constants.NULL_ADDRESS,
+    provider,
+);
 
 // tslint:disable:no-unnecessary-type-assertion
 describe('Asset Transfer Proxies', () => {
@@ -53,12 +60,17 @@ describe('Asset Transfer Proxies', () => {
     });
     before(async () => {
         const accounts = await web3Wrapper.getAvailableAddressesAsync();
-        const usedAddresses = ([owner, notAuthorized, exchangeAddress, makerAddress, takerAddress] = accounts);
+        const usedAddresses = ([owner, notAuthorized, exchangeAddress, makerAddress, takerAddress] = _.slice(
+            accounts,
+            0,
+            5,
+        ));
 
         erc20Wrapper = new ERC20Wrapper(provider, usedAddresses, owner);
         erc721Wrapper = new ERC721Wrapper(provider, usedAddresses, owner);
 
-        [zrxToken] = await erc20Wrapper.deployDummyTokensAsync();
+        const numDummyErc20ToDeploy = 1;
+        [zrxToken] = await erc20Wrapper.deployDummyTokensAsync(numDummyErc20ToDeploy, constants.DUMMY_TOKEN_DECIMALS);
         erc20Proxy = await erc20Wrapper.deployProxyAsync();
         await erc20Wrapper.setBalancesAndAllowancesAsync();
         await web3Wrapper.awaitTransactionSuccessAsync(
@@ -96,18 +108,21 @@ describe('Asset Transfer Proxies', () => {
             it('should successfully transfer tokens', async () => {
                 // Construct ERC20 asset data
                 const encodedAssetData = assetProxyUtils.encodeERC20AssetData(zrxToken.address);
-                const encodedAssetDataWithoutProxyId = encodedAssetData.slice(0, -2);
                 // Perform a transfer from makerAddress to takerAddress
                 const erc20Balances = await erc20Wrapper.getBalancesAsync();
                 const amount = new BigNumber(10);
+                const data = assetProxyInterface.transferFrom.getABIEncodedTransactionData(
+                    encodedAssetData,
+                    makerAddress,
+                    takerAddress,
+                    amount,
+                );
                 await web3Wrapper.awaitTransactionSuccessAsync(
-                    await erc20Proxy.transferFrom.sendTransactionAsync(
-                        encodedAssetDataWithoutProxyId,
-                        makerAddress,
-                        takerAddress,
-                        amount,
-                        { from: exchangeAddress },
-                    ),
+                    await web3Wrapper.sendTransactionAsync({
+                        to: erc20Proxy.address,
+                        data,
+                        from: exchangeAddress,
+                    }),
                     constants.AWAIT_TRANSACTION_MINED_MS,
                 );
                 // Verify transfer was successful
@@ -123,18 +138,21 @@ describe('Asset Transfer Proxies', () => {
             it('should do nothing if transferring 0 amount of a token', async () => {
                 // Construct ERC20 asset data
                 const encodedAssetData = assetProxyUtils.encodeERC20AssetData(zrxToken.address);
-                const encodedAssetDataWithoutProxyId = encodedAssetData.slice(0, -2);
                 // Perform a transfer from makerAddress to takerAddress
                 const erc20Balances = await erc20Wrapper.getBalancesAsync();
                 const amount = new BigNumber(0);
+                const data = assetProxyInterface.transferFrom.getABIEncodedTransactionData(
+                    encodedAssetData,
+                    makerAddress,
+                    takerAddress,
+                    amount,
+                );
                 await web3Wrapper.awaitTransactionSuccessAsync(
-                    await erc20Proxy.transferFrom.sendTransactionAsync(
-                        encodedAssetDataWithoutProxyId,
-                        makerAddress,
-                        takerAddress,
-                        amount,
-                        { from: exchangeAddress },
-                    ),
+                    await web3Wrapper.sendTransactionAsync({
+                        to: erc20Proxy.address,
+                        data,
+                        from: exchangeAddress,
+                    }),
                     constants.AWAIT_TRANSACTION_MINED_MS,
                 );
                 // Verify transfer was successful
@@ -152,7 +170,13 @@ describe('Asset Transfer Proxies', () => {
                 const encodedAssetData = assetProxyUtils.encodeERC20AssetData(zrxToken.address);
                 // Create allowance less than transfer amount. Set allowance on proxy.
                 const allowance = new BigNumber(0);
-                const transferAmount = new BigNumber(10);
+                const amount = new BigNumber(10);
+                const data = assetProxyInterface.transferFrom.getABIEncodedTransactionData(
+                    encodedAssetData,
+                    makerAddress,
+                    takerAddress,
+                    amount,
+                );
                 await web3Wrapper.awaitTransactionSuccessAsync(
                     await zrxToken.approve.sendTransactionAsync(erc20Proxy.address, allowance, {
                         from: makerAddress,
@@ -160,93 +184,42 @@ describe('Asset Transfer Proxies', () => {
                     constants.AWAIT_TRANSACTION_MINED_MS,
                 );
                 // Perform a transfer; expect this to fail.
-                return expectRevertOrAlwaysFailingTransactionAsync(
-                    erc20Proxy.transferFrom.sendTransactionAsync(
-                        encodedAssetData,
-                        makerAddress,
-                        takerAddress,
-                        transferAmount,
-                        { from: notAuthorized },
-                    ),
+                return expectRevertReasonOrAlwaysFailingTransactionAsync(
+                    web3Wrapper.sendTransactionAsync({
+                        to: erc20Proxy.address,
+                        data,
+                        from: exchangeAddress,
+                    }),
+                    RevertReason.TransferFailed,
                 );
             });
 
             it('should throw if requesting address is not authorized', async () => {
                 // Construct ERC20 asset data
                 const encodedAssetData = assetProxyUtils.encodeERC20AssetData(zrxToken.address);
-                const encodedAssetDataWithoutProxyId = encodedAssetData.slice(0, -2);
                 // Perform a transfer from makerAddress to takerAddress
                 const amount = new BigNumber(10);
-                return expectRevertOrAlwaysFailingTransactionAsync(
-                    erc20Proxy.transferFrom.sendTransactionAsync(
-                        encodedAssetDataWithoutProxyId,
-                        makerAddress,
-                        takerAddress,
-                        amount,
-                        {
-                            from: notAuthorized,
-                        },
-                    ),
-                );
-            });
-        });
-
-        describe('batchTransferFrom', () => {
-            it('should succesfully make multiple token transfers', async () => {
-                const erc20Balances = await erc20Wrapper.getBalancesAsync();
-
-                const encodedAssetData = assetProxyUtils.encodeERC20AssetData(zrxToken.address);
-                const encodedAssetDataWithoutProxyId = encodedAssetData.slice(0, -2);
-                const amount = new BigNumber(10);
-                const numTransfers = 2;
-                const assetData = _.times(numTransfers, () => encodedAssetDataWithoutProxyId);
-                const fromAddresses = _.times(numTransfers, () => makerAddress);
-                const toAddresses = _.times(numTransfers, () => takerAddress);
-                const amounts = _.times(numTransfers, () => amount);
-
-                const txHash = await erc20Proxy.batchTransferFrom.sendTransactionAsync(
-                    assetData,
-                    fromAddresses,
-                    toAddresses,
-                    amounts,
-                    { from: exchangeAddress },
-                );
-                const res = await web3Wrapper.awaitTransactionSuccessAsync(
-                    txHash,
-                    constants.AWAIT_TRANSACTION_MINED_MS,
-                );
-                const newBalances = await erc20Wrapper.getBalancesAsync();
-
-                expect(res.logs.length).to.equal(numTransfers);
-                expect(newBalances[makerAddress][zrxToken.address]).to.be.bignumber.equal(
-                    erc20Balances[makerAddress][zrxToken.address].minus(amount.times(numTransfers)),
-                );
-                expect(newBalances[takerAddress][zrxToken.address]).to.be.bignumber.equal(
-                    erc20Balances[takerAddress][zrxToken.address].add(amount.times(numTransfers)),
+                const data = assetProxyInterface.transferFrom.getABIEncodedTransactionData(
+                    encodedAssetData,
+                    makerAddress,
+                    takerAddress,
+                    amount,
                 );
-            });
-
-            it('should throw if not called by an authorized address', async () => {
-                const encodedAssetData = assetProxyUtils.encodeERC20AssetData(zrxToken.address);
-                const encodedAssetDataWithoutProxyId = encodedAssetData.slice(0, -2);
-                const amount = new BigNumber(10);
-                const numTransfers = 2;
-                const assetData = _.times(numTransfers, () => encodedAssetDataWithoutProxyId);
-                const fromAddresses = _.times(numTransfers, () => makerAddress);
-                const toAddresses = _.times(numTransfers, () => takerAddress);
-                const amounts = _.times(numTransfers, () => amount);
-
-                return expectRevertOrAlwaysFailingTransactionAsync(
-                    erc20Proxy.batchTransferFrom.sendTransactionAsync(assetData, fromAddresses, toAddresses, amounts, {
+                return expectRevertReasonOrAlwaysFailingTransactionAsync(
+                    web3Wrapper.sendTransactionAsync({
+                        to: erc20Proxy.address,
+                        data,
                         from: notAuthorized,
                     }),
+                    RevertReason.SenderNotAuthorized,
                 );
             });
         });
 
-        it('should have an id of 1', async () => {
+        it('should have an id of 0xf47261b0', async () => {
             const proxyId = await erc20Proxy.getProxyId.callAsync();
-            expect(proxyId).to.equal(1);
+            const expectedProxyId = '0xf47261b0';
+            expect(proxyId).to.equal(expectedProxyId);
         });
     });
 
@@ -255,20 +228,23 @@ describe('Asset Transfer Proxies', () => {
             it('should successfully transfer tokens', async () => {
                 // Construct ERC721 asset data
                 const encodedAssetData = assetProxyUtils.encodeERC721AssetData(erc721Token.address, erc721MakerTokenId);
-                const encodedAssetDataWithoutProxyId = encodedAssetData.slice(0, -2);
                 // Verify pre-condition
                 const ownerMakerAsset = await erc721Token.ownerOf.callAsync(erc721MakerTokenId);
                 expect(ownerMakerAsset).to.be.bignumber.equal(makerAddress);
                 // Perform a transfer from makerAddress to takerAddress
                 const amount = new BigNumber(1);
+                const data = assetProxyInterface.transferFrom.getABIEncodedTransactionData(
+                    encodedAssetData,
+                    makerAddress,
+                    takerAddress,
+                    amount,
+                );
                 await web3Wrapper.awaitTransactionSuccessAsync(
-                    await erc721Proxy.transferFrom.sendTransactionAsync(
-                        encodedAssetDataWithoutProxyId,
-                        makerAddress,
-                        takerAddress,
-                        amount,
-                        { from: exchangeAddress },
-                    ),
+                    await web3Wrapper.sendTransactionAsync({
+                        to: erc721Proxy.address,
+                        data,
+                        from: exchangeAddress,
+                    }),
                     constants.AWAIT_TRANSACTION_MINED_MS,
                 );
                 // Verify transfer was successful
@@ -279,23 +255,26 @@ describe('Asset Transfer Proxies', () => {
             it('should call onERC721Received when transferring to a smart contract without receiver data', async () => {
                 // Construct ERC721 asset data
                 const encodedAssetData = assetProxyUtils.encodeERC721AssetData(erc721Token.address, erc721MakerTokenId);
-                const encodedAssetDataWithoutProxyId = encodedAssetData.slice(0, -2);
                 // Verify pre-condition
                 const ownerMakerAsset = await erc721Token.ownerOf.callAsync(erc721MakerTokenId);
                 expect(ownerMakerAsset).to.be.bignumber.equal(makerAddress);
                 // Perform a transfer from makerAddress to takerAddress
                 const amount = new BigNumber(1);
-                const txHash = await erc721Proxy.transferFrom.sendTransactionAsync(
-                    encodedAssetDataWithoutProxyId,
+                const data = assetProxyInterface.transferFrom.getABIEncodedTransactionData(
+                    encodedAssetData,
                     makerAddress,
                     erc721Receiver.address,
                     amount,
-                    { from: exchangeAddress },
                 );
-                await web3Wrapper.awaitTransactionSuccessAsync(txHash, constants.AWAIT_TRANSACTION_MINED_MS);
-                // Parse transaction logs
                 const logDecoder = new LogDecoder(web3Wrapper, erc721Receiver.address);
-                const tx = await logDecoder.getTxWithDecodedLogsAsync(txHash);
+                const tx = await logDecoder.getTxWithDecodedLogsAsync(
+                    await web3Wrapper.sendTransactionAsync({
+                        to: erc721Proxy.address,
+                        data,
+                        from: exchangeAddress,
+                        gas: constants.TRANSFER_FROM_GAS,
+                    }),
+                );
                 // Verify that no log was emitted by erc721 receiver
                 expect(tx.logs.length).to.be.equal(1);
                 const tokenReceivedLog = tx.logs[0] as LogWithDecodedArgs<TokenReceivedContractEventArgs>;
@@ -315,23 +294,26 @@ describe('Asset Transfer Proxies', () => {
                     erc721MakerTokenId,
                     receiverData,
                 );
-                const encodedAssetDataWithoutProxyId = encodedAssetData.slice(0, -2);
                 // Verify pre-condition
                 const ownerMakerAsset = await erc721Token.ownerOf.callAsync(erc721MakerTokenId);
                 expect(ownerMakerAsset).to.be.bignumber.equal(makerAddress);
                 // Perform a transfer from makerAddress to takerAddress
                 const amount = new BigNumber(1);
-                const txHash = await erc721Proxy.transferFrom.sendTransactionAsync(
-                    encodedAssetDataWithoutProxyId,
+                const data = assetProxyInterface.transferFrom.getABIEncodedTransactionData(
+                    encodedAssetData,
                     makerAddress,
                     erc721Receiver.address,
                     amount,
-                    { from: exchangeAddress },
                 );
-                await web3Wrapper.awaitTransactionSuccessAsync(txHash, constants.AWAIT_TRANSACTION_MINED_MS);
-                // Parse transaction logs
                 const logDecoder = new LogDecoder(web3Wrapper, erc721Receiver.address);
-                const tx = await logDecoder.getTxWithDecodedLogsAsync(txHash);
+                const tx = await logDecoder.getTxWithDecodedLogsAsync(
+                    await web3Wrapper.sendTransactionAsync({
+                        to: erc721Proxy.address,
+                        data,
+                        from: exchangeAddress,
+                        gas: constants.TRANSFER_FROM_GAS,
+                    }),
+                );
                 // Validate log emitted by erc721 receiver
                 expect(tx.logs.length).to.be.equal(1);
                 const tokenReceivedLog = tx.logs[0] as LogWithDecodedArgs<TokenReceivedContractEventArgs>;
@@ -351,164 +333,130 @@ describe('Asset Transfer Proxies', () => {
                     erc721MakerTokenId,
                     receiverData,
                 );
-                const encodedAssetDataWithoutProxyId = encodedAssetData.slice(0, -2);
                 // Verify pre-condition
                 const ownerMakerAsset = await erc721Token.ownerOf.callAsync(erc721MakerTokenId);
                 expect(ownerMakerAsset).to.be.bignumber.equal(makerAddress);
                 // Perform a transfer from makerAddress to takerAddress
                 const amount = new BigNumber(1);
-                return expectRevertOrAlwaysFailingTransactionAsync(
-                    erc721Proxy.transferFrom.sendTransactionAsync(
-                        encodedAssetDataWithoutProxyId,
-                        makerAddress,
-                        erc20Proxy.address, // the ERC20 proxy does not have an ERC721 receiver
-                        amount,
-                        { from: exchangeAddress },
-                    ),
+                const data = assetProxyInterface.transferFrom.getABIEncodedTransactionData(
+                    encodedAssetData,
+                    makerAddress,
+                    erc20Proxy.address, // the ERC20 proxy does not have an ERC721 receiver
+                    amount,
+                );
+                return expectRevertReasonOrAlwaysFailingTransactionAsync(
+                    web3Wrapper.sendTransactionAsync({
+                        to: erc721Proxy.address,
+                        data,
+                        from: exchangeAddress,
+                        gas: constants.TRANSFER_FROM_GAS,
+                    }),
+                    RevertReason.TransferFailed,
                 );
             });
 
             it('should throw if transferring 0 amount of a token', async () => {
                 // Construct ERC721 asset data
                 const encodedAssetData = assetProxyUtils.encodeERC721AssetData(erc721Token.address, erc721MakerTokenId);
-                const encodedAssetDataWithoutProxyId = encodedAssetData.slice(0, -2);
                 // Verify pre-condition
                 const ownerMakerAsset = await erc721Token.ownerOf.callAsync(erc721MakerTokenId);
                 expect(ownerMakerAsset).to.be.bignumber.equal(makerAddress);
                 // Perform a transfer from makerAddress to takerAddress
                 const amount = new BigNumber(0);
-                return expectRevertOrAlwaysFailingTransactionAsync(
-                    erc721Proxy.transferFrom.sendTransactionAsync(
-                        encodedAssetDataWithoutProxyId,
-                        makerAddress,
-                        takerAddress,
-                        amount,
-                        { from: exchangeAddress },
-                    ),
+                const data = assetProxyInterface.transferFrom.getABIEncodedTransactionData(
+                    encodedAssetData,
+                    makerAddress,
+                    takerAddress,
+                    amount,
+                );
+                return expectRevertReasonOrAlwaysFailingTransactionAsync(
+                    web3Wrapper.sendTransactionAsync({
+                        to: erc721Proxy.address,
+                        data,
+                        from: exchangeAddress,
+                    }),
+                    RevertReason.InvalidAmount,
                 );
             });
 
             it('should throw if transferring > 1 amount of a token', async () => {
                 // Construct ERC721 asset data
                 const encodedAssetData = assetProxyUtils.encodeERC721AssetData(erc721Token.address, erc721MakerTokenId);
-                const encodedAssetDataWithoutProxyId = encodedAssetData.slice(0, -2);
                 // Verify pre-condition
                 const ownerMakerAsset = await erc721Token.ownerOf.callAsync(erc721MakerTokenId);
                 expect(ownerMakerAsset).to.be.bignumber.equal(makerAddress);
                 // Perform a transfer from makerAddress to takerAddress
                 const amount = new BigNumber(500);
-                return expectRevertOrAlwaysFailingTransactionAsync(
-                    erc721Proxy.transferFrom.sendTransactionAsync(
-                        encodedAssetDataWithoutProxyId,
-                        makerAddress,
-                        takerAddress,
-                        amount,
-                        { from: exchangeAddress },
-                    ),
+                const data = assetProxyInterface.transferFrom.getABIEncodedTransactionData(
+                    encodedAssetData,
+                    makerAddress,
+                    takerAddress,
+                    amount,
+                );
+                return expectRevertReasonOrAlwaysFailingTransactionAsync(
+                    web3Wrapper.sendTransactionAsync({
+                        to: erc721Proxy.address,
+                        data,
+                        from: exchangeAddress,
+                    }),
+                    RevertReason.InvalidAmount,
                 );
             });
 
             it('should throw if allowances are too low', async () => {
                 // Construct ERC721 asset data
                 const encodedAssetData = assetProxyUtils.encodeERC721AssetData(erc721Token.address, erc721MakerTokenId);
-                const encodedAssetDataWithoutProxyId = encodedAssetData.slice(0, -2);
                 // Remove transfer approval for makerAddress.
                 await web3Wrapper.awaitTransactionSuccessAsync(
-                    await erc721Token.setApprovalForAll.sendTransactionAsync(erc721Proxy.address, false, {
+                    await erc721Token.approve.sendTransactionAsync(constants.NULL_ADDRESS, erc721MakerTokenId, {
                         from: makerAddress,
                     }),
                     constants.AWAIT_TRANSACTION_MINED_MS,
                 );
                 // Perform a transfer; expect this to fail.
                 const amount = new BigNumber(1);
-                return expectRevertOrAlwaysFailingTransactionAsync(
-                    erc20Proxy.transferFrom.sendTransactionAsync(
-                        encodedAssetDataWithoutProxyId,
-                        makerAddress,
-                        takerAddress,
-                        amount,
-                        {
-                            from: notAuthorized,
-                        },
-                    ),
+                const data = assetProxyInterface.transferFrom.getABIEncodedTransactionData(
+                    encodedAssetData,
+                    makerAddress,
+                    takerAddress,
+                    amount,
+                );
+                return expectRevertReasonOrAlwaysFailingTransactionAsync(
+                    web3Wrapper.sendTransactionAsync({
+                        to: erc721Proxy.address,
+                        data,
+                        from: exchangeAddress,
+                    }),
+                    RevertReason.TransferFailed,
                 );
             });
 
             it('should throw if requesting address is not authorized', async () => {
                 // Construct ERC721 asset data
                 const encodedAssetData = assetProxyUtils.encodeERC721AssetData(erc721Token.address, erc721MakerTokenId);
-                const encodedAssetDataWithoutProxyId = encodedAssetData.slice(0, -2);
                 // Perform a transfer from makerAddress to takerAddress
                 const amount = new BigNumber(1);
-                return expectRevertOrAlwaysFailingTransactionAsync(
-                    erc721Proxy.transferFrom.sendTransactionAsync(
-                        encodedAssetDataWithoutProxyId,
-                        makerAddress,
-                        takerAddress,
-                        amount,
-                        { from: notAuthorized },
-                    ),
-                );
-            });
-        });
-
-        describe('batchTransferFrom', () => {
-            it('should succesfully make multiple token transfers', async () => {
-                const erc721TokensById = await erc721Wrapper.getBalancesAsync();
-                const [makerTokenIdA, makerTokenIdB] = erc721TokensById[makerAddress][erc721Token.address];
-
-                const numTransfers = 2;
-                const assetData = [
-                    assetProxyUtils.encodeERC721AssetData(erc721Token.address, makerTokenIdA).slice(0, -2),
-                    assetProxyUtils.encodeERC721AssetData(erc721Token.address, makerTokenIdB).slice(0, -2),
-                ];
-                const fromAddresses = _.times(numTransfers, () => makerAddress);
-                const toAddresses = _.times(numTransfers, () => takerAddress);
-                const amounts = _.times(numTransfers, () => new BigNumber(1));
-
-                const txHash = await erc721Proxy.batchTransferFrom.sendTransactionAsync(
-                    assetData,
-                    fromAddresses,
-                    toAddresses,
-                    amounts,
-                    { from: exchangeAddress },
-                );
-                const res = await web3Wrapper.awaitTransactionSuccessAsync(
-                    txHash,
-                    constants.AWAIT_TRANSACTION_MINED_MS,
+                const data = assetProxyInterface.transferFrom.getABIEncodedTransactionData(
+                    encodedAssetData,
+                    makerAddress,
+                    takerAddress,
+                    amount,
                 );
-                expect(res.logs.length).to.equal(numTransfers);
-
-                const newOwnerMakerAssetA = await erc721Token.ownerOf.callAsync(makerTokenIdA);
-                const newOwnerMakerAssetB = await erc721Token.ownerOf.callAsync(makerTokenIdB);
-                expect(newOwnerMakerAssetA).to.be.bignumber.equal(takerAddress);
-                expect(newOwnerMakerAssetB).to.be.bignumber.equal(takerAddress);
-            });
-
-            it('should throw if not called by an authorized address', async () => {
-                const erc721TokensById = await erc721Wrapper.getBalancesAsync();
-                const [makerTokenIdA, makerTokenIdB] = erc721TokensById[makerAddress][erc721Token.address];
-
-                const numTransfers = 2;
-                const assetData = [
-                    assetProxyUtils.encodeERC721AssetData(erc721Token.address, makerTokenIdA).slice(0, -2),
-                    assetProxyUtils.encodeERC721AssetData(erc721Token.address, makerTokenIdB).slice(0, -2),
-                ];
-                const fromAddresses = _.times(numTransfers, () => makerAddress);
-                const toAddresses = _.times(numTransfers, () => takerAddress);
-                const amounts = _.times(numTransfers, () => new BigNumber(1));
-
-                return expectRevertOrAlwaysFailingTransactionAsync(
-                    erc721Proxy.batchTransferFrom.sendTransactionAsync(assetData, fromAddresses, toAddresses, amounts, {
+                return expectRevertReasonOrAlwaysFailingTransactionAsync(
+                    web3Wrapper.sendTransactionAsync({
+                        to: erc721Proxy.address,
+                        data,
                         from: notAuthorized,
                     }),
+                    RevertReason.SenderNotAuthorized,
                 );
             });
         });
 
-        it('should have an id of 2', async () => {
+        it('should have an id of 0x08e937fa', async () => {
             const proxyId = await erc721Proxy.getProxyId.callAsync();
-            expect(proxyId).to.equal(2);
+            const expectedProxyId = '0x08e937fa';
+            expect(proxyId).to.equal(expectedProxyId);
         });
     });
 });
diff --git a/packages/contracts/test/exchange/core.ts b/packages/contracts/test/exchange/core.ts
index ff652d3aa..db56623f9 100644
--- a/packages/contracts/test/exchange/core.ts
+++ b/packages/contracts/test/exchange/core.ts
@@ -1,31 +1,28 @@
 import { BlockchainLifecycle } from '@0xproject/dev-utils';
 import { assetProxyUtils, orderHashUtils } from '@0xproject/order-utils';
-import { AssetProxyId, SignedOrder } from '@0xproject/types';
+import { RevertReason, SignedOrder } from '@0xproject/types';
 import { BigNumber } from '@0xproject/utils';
 import { Web3Wrapper } from '@0xproject/web3-wrapper';
 import * as chai from 'chai';
 import { LogWithDecodedArgs } from 'ethereum-types';
 import ethUtil = require('ethereumjs-util');
-
-import { DummyERC20TokenContract } from '../../src/generated_contract_wrappers/dummy_e_r_c20_token';
-import { DummyERC721TokenContract } from '../../src/generated_contract_wrappers/dummy_e_r_c721_token';
-import { ERC20ProxyContract } from '../../src/generated_contract_wrappers/e_r_c20_proxy';
-import { ERC721ProxyContract } from '../../src/generated_contract_wrappers/e_r_c721_proxy';
-import {
-    CancelContractEventArgs,
-    ExchangeContract,
-    FillContractEventArgs,
-} from '../../src/generated_contract_wrappers/exchange';
-import { artifacts } from '../../src/utils/artifacts';
-import { expectRevertOrAlwaysFailingTransactionAsync } from '../../src/utils/assertions';
-import { chaiSetup } from '../../src/utils/chai_setup';
-import { constants } from '../../src/utils/constants';
-import { ERC20Wrapper } from '../../src/utils/erc20_wrapper';
-import { ERC721Wrapper } from '../../src/utils/erc721_wrapper';
-import { ExchangeWrapper } from '../../src/utils/exchange_wrapper';
-import { OrderFactory } from '../../src/utils/order_factory';
-import { ERC20BalancesByOwner } from '../../src/utils/types';
-import { provider, txDefaults, web3Wrapper } from '../../src/utils/web3_wrapper';
+import * as _ from 'lodash';
+
+import { DummyERC20TokenContract } from '../../generated_contract_wrappers/dummy_e_r_c20_token';
+import { DummyERC721TokenContract } from '../../generated_contract_wrappers/dummy_e_r_c721_token';
+import { ERC20ProxyContract } from '../../generated_contract_wrappers/e_r_c20_proxy';
+import { ERC721ProxyContract } from '../../generated_contract_wrappers/e_r_c721_proxy';
+import { CancelContractEventArgs, ExchangeContract } from '../../generated_contract_wrappers/exchange';
+import { artifacts } from '../utils/artifacts';
+import { expectRevertReasonOrAlwaysFailingTransactionAsync } from '../utils/assertions';
+import { chaiSetup } from '../utils/chai_setup';
+import { constants } from '../utils/constants';
+import { ERC20Wrapper } from '../utils/erc20_wrapper';
+import { ERC721Wrapper } from '../utils/erc721_wrapper';
+import { ExchangeWrapper } from '../utils/exchange_wrapper';
+import { OrderFactory } from '../utils/order_factory';
+import { ERC20BalancesByOwner } from '../utils/types';
+import { provider, txDefaults, web3Wrapper } from '../utils/web3_wrapper';
 
 chaiSetup.configure();
 const expect = chai.expect;
@@ -66,12 +63,16 @@ describe('Exchange core', () => {
     });
     before(async () => {
         const accounts = await web3Wrapper.getAvailableAddressesAsync();
-        const usedAddresses = ([owner, makerAddress, takerAddress, feeRecipientAddress] = accounts);
+        const usedAddresses = ([owner, makerAddress, takerAddress, feeRecipientAddress] = _.slice(accounts, 0, 4));
 
         erc20Wrapper = new ERC20Wrapper(provider, usedAddresses, owner);
         erc721Wrapper = new ERC721Wrapper(provider, usedAddresses, owner);
 
-        [erc20TokenA, erc20TokenB, zrxToken] = await erc20Wrapper.deployDummyTokensAsync();
+        const numDummyErc20ToDeploy = 3;
+        [erc20TokenA, erc20TokenB, zrxToken] = await erc20Wrapper.deployDummyTokensAsync(
+            numDummyErc20ToDeploy,
+            constants.DUMMY_TOKEN_DECIMALS,
+        );
         erc20Proxy = await erc20Wrapper.deployProxyAsync();
         await erc20Wrapper.setBalancesAndAllowancesAsync();
 
@@ -86,11 +87,11 @@ describe('Exchange core', () => {
             artifacts.Exchange,
             provider,
             txDefaults,
-            zrxToken.address,
+            assetProxyUtils.encodeERC20AssetData(zrxToken.address),
         );
         exchangeWrapper = new ExchangeWrapper(exchange, provider);
-        await exchangeWrapper.registerAssetProxyAsync(AssetProxyId.ERC20, erc20Proxy.address, owner);
-        await exchangeWrapper.registerAssetProxyAsync(AssetProxyId.ERC721, erc721Proxy.address, owner);
+        await exchangeWrapper.registerAssetProxyAsync(erc20Proxy.address, owner);
+        await exchangeWrapper.registerAssetProxyAsync(erc721Proxy.address, owner);
 
         await web3Wrapper.awaitTransactionSuccessAsync(
             await erc20Proxy.addAuthorizedAddress.sendTransactionAsync(exchange.address, {
@@ -130,295 +131,6 @@ describe('Exchange core', () => {
             erc20Balances = await erc20Wrapper.getBalancesAsync();
             signedOrder = orderFactory.newSignedOrder();
         });
-        it('should transfer the correct amounts when makerAssetAmount === takerAssetAmount', async () => {
-            signedOrder = orderFactory.newSignedOrder({
-                makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(100), 18),
-                takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(100), 18),
-            });
-
-            const takerAssetFilledAmountBefore = await exchangeWrapper.getTakerAssetFilledAmountAsync(
-                orderHashUtils.getOrderHashHex(signedOrder),
-            );
-            expect(takerAssetFilledAmountBefore).to.be.bignumber.equal(0);
-
-            const takerAssetFillAmount = signedOrder.takerAssetAmount.div(2);
-            await exchangeWrapper.fillOrderAsync(signedOrder, takerAddress, { takerAssetFillAmount });
-
-            const makerAmountBoughtAfter = await exchangeWrapper.getTakerAssetFilledAmountAsync(
-                orderHashUtils.getOrderHashHex(signedOrder),
-            );
-            expect(makerAmountBoughtAfter).to.be.bignumber.equal(takerAssetFillAmount);
-
-            const newBalances = await erc20Wrapper.getBalancesAsync();
-
-            const makerAssetFilledAmount = takerAssetFillAmount
-                .times(signedOrder.makerAssetAmount)
-                .dividedToIntegerBy(signedOrder.takerAssetAmount);
-            const makerFeePaid = signedOrder.makerFee
-                .times(makerAssetFilledAmount)
-                .dividedToIntegerBy(signedOrder.makerAssetAmount);
-            const takerFeePaid = signedOrder.takerFee
-                .times(makerAssetFilledAmount)
-                .dividedToIntegerBy(signedOrder.makerAssetAmount);
-            expect(newBalances[makerAddress][defaultMakerAssetAddress]).to.be.bignumber.equal(
-                erc20Balances[makerAddress][defaultMakerAssetAddress].minus(makerAssetFilledAmount),
-            );
-            expect(newBalances[makerAddress][defaultTakerAssetAddress]).to.be.bignumber.equal(
-                erc20Balances[makerAddress][defaultTakerAssetAddress].add(takerAssetFillAmount),
-            );
-            expect(newBalances[makerAddress][zrxToken.address]).to.be.bignumber.equal(
-                erc20Balances[makerAddress][zrxToken.address].minus(makerFeePaid),
-            );
-            expect(newBalances[takerAddress][defaultTakerAssetAddress]).to.be.bignumber.equal(
-                erc20Balances[takerAddress][defaultTakerAssetAddress].minus(takerAssetFillAmount),
-            );
-            expect(newBalances[takerAddress][defaultMakerAssetAddress]).to.be.bignumber.equal(
-                erc20Balances[takerAddress][defaultMakerAssetAddress].add(makerAssetFilledAmount),
-            );
-            expect(newBalances[takerAddress][zrxToken.address]).to.be.bignumber.equal(
-                erc20Balances[takerAddress][zrxToken.address].minus(takerFeePaid),
-            );
-            expect(newBalances[feeRecipientAddress][zrxToken.address]).to.be.bignumber.equal(
-                erc20Balances[feeRecipientAddress][zrxToken.address].add(makerFeePaid.add(takerFeePaid)),
-            );
-        });
-
-        it('should transfer the correct amounts when makerAssetAmount > takerAssetAmount', async () => {
-            signedOrder = orderFactory.newSignedOrder({
-                makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(200), 18),
-                takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(100), 18),
-            });
-
-            const takerAssetFilledAmountBefore = await exchangeWrapper.getTakerAssetFilledAmountAsync(
-                orderHashUtils.getOrderHashHex(signedOrder),
-            );
-            expect(takerAssetFilledAmountBefore).to.be.bignumber.equal(0);
-
-            const takerAssetFillAmount = signedOrder.takerAssetAmount.div(2);
-            await exchangeWrapper.fillOrderAsync(signedOrder, takerAddress, { takerAssetFillAmount });
-
-            const makerAmountBoughtAfter = await exchangeWrapper.getTakerAssetFilledAmountAsync(
-                orderHashUtils.getOrderHashHex(signedOrder),
-            );
-            expect(makerAmountBoughtAfter).to.be.bignumber.equal(takerAssetFillAmount);
-
-            const newBalances = await erc20Wrapper.getBalancesAsync();
-
-            const makerAssetFilledAmount = takerAssetFillAmount
-                .times(signedOrder.makerAssetAmount)
-                .dividedToIntegerBy(signedOrder.takerAssetAmount);
-            const makerFeePaid = signedOrder.makerFee
-                .times(makerAssetFilledAmount)
-                .dividedToIntegerBy(signedOrder.makerAssetAmount);
-            const takerFeePaid = signedOrder.takerFee
-                .times(makerAssetFilledAmount)
-                .dividedToIntegerBy(signedOrder.makerAssetAmount);
-            expect(newBalances[makerAddress][defaultMakerAssetAddress]).to.be.bignumber.equal(
-                erc20Balances[makerAddress][defaultMakerAssetAddress].minus(makerAssetFilledAmount),
-            );
-            expect(newBalances[makerAddress][defaultTakerAssetAddress]).to.be.bignumber.equal(
-                erc20Balances[makerAddress][defaultTakerAssetAddress].add(takerAssetFillAmount),
-            );
-            expect(newBalances[makerAddress][zrxToken.address]).to.be.bignumber.equal(
-                erc20Balances[makerAddress][zrxToken.address].minus(makerFeePaid),
-            );
-            expect(newBalances[takerAddress][defaultTakerAssetAddress]).to.be.bignumber.equal(
-                erc20Balances[takerAddress][defaultTakerAssetAddress].minus(takerAssetFillAmount),
-            );
-            expect(newBalances[takerAddress][defaultMakerAssetAddress]).to.be.bignumber.equal(
-                erc20Balances[takerAddress][defaultMakerAssetAddress].add(makerAssetFilledAmount),
-            );
-            expect(newBalances[takerAddress][zrxToken.address]).to.be.bignumber.equal(
-                erc20Balances[takerAddress][zrxToken.address].minus(takerFeePaid),
-            );
-            expect(newBalances[feeRecipientAddress][zrxToken.address]).to.be.bignumber.equal(
-                erc20Balances[feeRecipientAddress][zrxToken.address].add(makerFeePaid.add(takerFeePaid)),
-            );
-        });
-
-        it('should transfer the correct amounts when makerAssetAmount < takerAssetAmount', async () => {
-            signedOrder = orderFactory.newSignedOrder({
-                makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(100), 18),
-                takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(200), 18),
-            });
-
-            const takerAssetFilledAmountBefore = await exchangeWrapper.getTakerAssetFilledAmountAsync(
-                orderHashUtils.getOrderHashHex(signedOrder),
-            );
-            expect(takerAssetFilledAmountBefore).to.be.bignumber.equal(0);
-
-            const takerAssetFillAmount = signedOrder.takerAssetAmount.div(2);
-            await exchangeWrapper.fillOrderAsync(signedOrder, takerAddress, { takerAssetFillAmount });
-
-            const makerAmountBoughtAfter = await exchangeWrapper.getTakerAssetFilledAmountAsync(
-                orderHashUtils.getOrderHashHex(signedOrder),
-            );
-            expect(makerAmountBoughtAfter).to.be.bignumber.equal(takerAssetFillAmount);
-
-            const newBalances = await erc20Wrapper.getBalancesAsync();
-
-            const makerAssetFilledAmount = takerAssetFillAmount
-                .times(signedOrder.makerAssetAmount)
-                .dividedToIntegerBy(signedOrder.takerAssetAmount);
-            const makerFeePaid = signedOrder.makerFee
-                .times(makerAssetFilledAmount)
-                .dividedToIntegerBy(signedOrder.makerAssetAmount);
-            const takerFeePaid = signedOrder.takerFee
-                .times(makerAssetFilledAmount)
-                .dividedToIntegerBy(signedOrder.makerAssetAmount);
-            expect(newBalances[makerAddress][defaultMakerAssetAddress]).to.be.bignumber.equal(
-                erc20Balances[makerAddress][defaultMakerAssetAddress].minus(makerAssetFilledAmount),
-            );
-            expect(newBalances[makerAddress][defaultTakerAssetAddress]).to.be.bignumber.equal(
-                erc20Balances[makerAddress][defaultTakerAssetAddress].add(takerAssetFillAmount),
-            );
-            expect(newBalances[makerAddress][zrxToken.address]).to.be.bignumber.equal(
-                erc20Balances[makerAddress][zrxToken.address].minus(makerFeePaid),
-            );
-            expect(newBalances[takerAddress][defaultTakerAssetAddress]).to.be.bignumber.equal(
-                erc20Balances[takerAddress][defaultTakerAssetAddress].minus(takerAssetFillAmount),
-            );
-            expect(newBalances[takerAddress][defaultMakerAssetAddress]).to.be.bignumber.equal(
-                erc20Balances[takerAddress][defaultMakerAssetAddress].add(makerAssetFilledAmount),
-            );
-            expect(newBalances[takerAddress][zrxToken.address]).to.be.bignumber.equal(
-                erc20Balances[takerAddress][zrxToken.address].minus(takerFeePaid),
-            );
-            expect(newBalances[feeRecipientAddress][zrxToken.address]).to.be.bignumber.equal(
-                erc20Balances[feeRecipientAddress][zrxToken.address].add(makerFeePaid.add(takerFeePaid)),
-            );
-        });
-
-        it('should transfer the correct amounts when taker is specified and order is claimed by taker', async () => {
-            signedOrder = orderFactory.newSignedOrder({
-                takerAddress,
-                makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(100), 18),
-                takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(200), 18),
-            });
-
-            const takerAssetFilledAmountBefore = await exchangeWrapper.getTakerAssetFilledAmountAsync(
-                orderHashUtils.getOrderHashHex(signedOrder),
-            );
-            expect(takerAssetFilledAmountBefore).to.be.bignumber.equal(0);
-
-            const takerAssetFillAmount = signedOrder.takerAssetAmount.div(2);
-            await exchangeWrapper.fillOrderAsync(signedOrder, takerAddress, { takerAssetFillAmount });
-
-            const makerAmountBoughtAfter = await exchangeWrapper.getTakerAssetFilledAmountAsync(
-                orderHashUtils.getOrderHashHex(signedOrder),
-            );
-            const expectedMakerAmountBoughtAfter = takerAssetFillAmount.add(takerAssetFilledAmountBefore);
-            expect(makerAmountBoughtAfter).to.be.bignumber.equal(expectedMakerAmountBoughtAfter);
-
-            const newBalances = await erc20Wrapper.getBalancesAsync();
-
-            const makerAssetFilledAmount = takerAssetFillAmount
-                .times(signedOrder.makerAssetAmount)
-                .dividedToIntegerBy(signedOrder.takerAssetAmount);
-            const makerFeePaid = signedOrder.makerFee
-                .times(makerAssetFilledAmount)
-                .dividedToIntegerBy(signedOrder.makerAssetAmount);
-            const takerFeePaid = signedOrder.takerFee
-                .times(makerAssetFilledAmount)
-                .dividedToIntegerBy(signedOrder.makerAssetAmount);
-            expect(newBalances[makerAddress][defaultMakerAssetAddress]).to.be.bignumber.equal(
-                erc20Balances[makerAddress][defaultMakerAssetAddress].minus(makerAssetFilledAmount),
-            );
-            expect(newBalances[makerAddress][defaultTakerAssetAddress]).to.be.bignumber.equal(
-                erc20Balances[makerAddress][defaultTakerAssetAddress].add(takerAssetFillAmount),
-            );
-            expect(newBalances[makerAddress][zrxToken.address]).to.be.bignumber.equal(
-                erc20Balances[makerAddress][zrxToken.address].minus(makerFeePaid),
-            );
-            expect(newBalances[takerAddress][defaultTakerAssetAddress]).to.be.bignumber.equal(
-                erc20Balances[takerAddress][defaultTakerAssetAddress].minus(takerAssetFillAmount),
-            );
-            expect(newBalances[takerAddress][defaultMakerAssetAddress]).to.be.bignumber.equal(
-                erc20Balances[takerAddress][defaultMakerAssetAddress].add(makerAssetFilledAmount),
-            );
-            expect(newBalances[takerAddress][zrxToken.address]).to.be.bignumber.equal(
-                erc20Balances[takerAddress][zrxToken.address].minus(takerFeePaid),
-            );
-            expect(newBalances[feeRecipientAddress][zrxToken.address]).to.be.bignumber.equal(
-                erc20Balances[feeRecipientAddress][zrxToken.address].add(makerFeePaid.add(takerFeePaid)),
-            );
-        });
-
-        it('should fill remaining value if takerAssetFillAmount > remaining takerAssetAmount', async () => {
-            const takerAssetFillAmount = signedOrder.takerAssetAmount.div(2);
-            await exchangeWrapper.fillOrderAsync(signedOrder, takerAddress, { takerAssetFillAmount });
-
-            const res = await exchangeWrapper.fillOrderAsync(signedOrder, takerAddress, {
-                takerAssetFillAmount: signedOrder.takerAssetAmount,
-            });
-            const log = res.logs[0] as LogWithDecodedArgs<FillContractEventArgs>;
-            expect(log.args.takerAssetFilledAmount).to.be.bignumber.equal(
-                signedOrder.takerAssetAmount.minus(takerAssetFillAmount),
-            );
-            const newBalances = await erc20Wrapper.getBalancesAsync();
-
-            expect(newBalances[makerAddress][defaultMakerAssetAddress]).to.be.bignumber.equal(
-                erc20Balances[makerAddress][defaultMakerAssetAddress].minus(signedOrder.makerAssetAmount),
-            );
-            expect(newBalances[makerAddress][defaultTakerAssetAddress]).to.be.bignumber.equal(
-                erc20Balances[makerAddress][defaultTakerAssetAddress].add(signedOrder.takerAssetAmount),
-            );
-            expect(newBalances[makerAddress][zrxToken.address]).to.be.bignumber.equal(
-                erc20Balances[makerAddress][zrxToken.address].minus(signedOrder.makerFee),
-            );
-            expect(newBalances[takerAddress][defaultTakerAssetAddress]).to.be.bignumber.equal(
-                erc20Balances[takerAddress][defaultTakerAssetAddress].minus(signedOrder.takerAssetAmount),
-            );
-            expect(newBalances[takerAddress][defaultMakerAssetAddress]).to.be.bignumber.equal(
-                erc20Balances[takerAddress][defaultMakerAssetAddress].add(signedOrder.makerAssetAmount),
-            );
-            expect(newBalances[takerAddress][zrxToken.address]).to.be.bignumber.equal(
-                erc20Balances[takerAddress][zrxToken.address].minus(signedOrder.takerFee),
-            );
-            expect(newBalances[feeRecipientAddress][zrxToken.address]).to.be.bignumber.equal(
-                erc20Balances[feeRecipientAddress][zrxToken.address].add(
-                    signedOrder.makerFee.add(signedOrder.takerFee),
-                ),
-            );
-        });
-
-        it('should log 1 event with the correct arguments when order has a feeRecipient', async () => {
-            const divisor = 2;
-            const res = await exchangeWrapper.fillOrderAsync(signedOrder, takerAddress, {
-                takerAssetFillAmount: signedOrder.takerAssetAmount.div(divisor),
-            });
-            expect(res.logs).to.have.length(1);
-
-            const log = res.logs[0] as LogWithDecodedArgs<FillContractEventArgs>;
-            const logArgs = log.args;
-            const expectedFilledMakerAssetAmount = signedOrder.makerAssetAmount.div(divisor);
-            const expectedFilledTakerAssetAmount = signedOrder.takerAssetAmount.div(divisor);
-            const expectedFeeMPaid = signedOrder.makerFee.div(divisor);
-            const expectedFeeTPaid = signedOrder.takerFee.div(divisor);
-
-            expect(signedOrder.makerAddress).to.be.equal(logArgs.makerAddress);
-            expect(takerAddress).to.be.equal(logArgs.takerAddress);
-            expect(takerAddress).to.be.equal(logArgs.senderAddress);
-            expect(signedOrder.feeRecipientAddress).to.be.equal(logArgs.feeRecipientAddress);
-            expect(signedOrder.makerAssetData).to.be.equal(logArgs.makerAssetData);
-            expect(signedOrder.takerAssetData).to.be.equal(logArgs.takerAssetData);
-            expect(expectedFilledMakerAssetAmount).to.be.bignumber.equal(logArgs.makerAssetFilledAmount);
-            expect(expectedFilledTakerAssetAmount).to.be.bignumber.equal(logArgs.takerAssetFilledAmount);
-            expect(expectedFeeMPaid).to.be.bignumber.equal(logArgs.makerFeePaid);
-            expect(expectedFeeTPaid).to.be.bignumber.equal(logArgs.takerFeePaid);
-            expect(orderHashUtils.getOrderHashHex(signedOrder)).to.be.equal(logArgs.orderHash);
-        });
-
-        it('should throw when taker is specified and order is claimed by other', async () => {
-            signedOrder = orderFactory.newSignedOrder({
-                takerAddress: feeRecipientAddress,
-                makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(100), 18),
-                takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(200), 18),
-            });
-            return expectRevertOrAlwaysFailingTransactionAsync(
-                exchangeWrapper.fillOrderAsync(signedOrder, takerAddress),
-            );
-        });
 
         it('should throw if signature is invalid', async () => {
             signedOrder = orderFactory.newSignedOrder({
@@ -432,98 +144,18 @@ describe('Exchange core', () => {
             const invalidSigBuff = Buffer.concat([v, invalidR, invalidS, signatureType]);
             const invalidSigHex = `0x${invalidSigBuff.toString('hex')}`;
             signedOrder.signature = invalidSigHex;
-            return expectRevertOrAlwaysFailingTransactionAsync(
-                exchangeWrapper.fillOrderAsync(signedOrder, takerAddress),
-            );
-        });
-
-        it('should throw if makerAssetAmount is 0', async () => {
-            signedOrder = orderFactory.newSignedOrder({
-                makerAssetAmount: new BigNumber(0),
-            });
-
-            return expectRevertOrAlwaysFailingTransactionAsync(
-                exchangeWrapper.fillOrderAsync(signedOrder, takerAddress),
-            );
-        });
-
-        it('should throw if takerAssetAmount is 0', async () => {
-            signedOrder = orderFactory.newSignedOrder({
-                takerAssetAmount: new BigNumber(0),
-            });
-
-            return expectRevertOrAlwaysFailingTransactionAsync(
-                exchangeWrapper.fillOrderAsync(signedOrder, takerAddress),
-            );
-        });
-
-        it('should throw if takerAssetFillAmount is 0', async () => {
-            signedOrder = orderFactory.newSignedOrder();
-
-            return expectRevertOrAlwaysFailingTransactionAsync(
-                exchangeWrapper.fillOrderAsync(signedOrder, takerAddress, {
-                    takerAssetFillAmount: new BigNumber(0),
-                }),
-            );
-        });
-
-        it('should throw if maker erc20Balances are too low to fill order', async () => {
-            signedOrder = orderFactory.newSignedOrder({
-                makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(100000), 18),
-            });
-
-            return expectRevertOrAlwaysFailingTransactionAsync(
-                exchangeWrapper.fillOrderAsync(signedOrder, takerAddress),
-            );
-        });
-
-        it('should throw if taker erc20Balances are too low to fill order', async () => {
-            signedOrder = orderFactory.newSignedOrder({
-                takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(100000), 18),
-            });
-            return expectRevertOrAlwaysFailingTransactionAsync(
-                exchangeWrapper.fillOrderAsync(signedOrder, takerAddress),
-            );
-        });
-
-        it('should throw if maker allowances are too low to fill order', async () => {
-            await web3Wrapper.awaitTransactionSuccessAsync(
-                await erc20TokenA.approve.sendTransactionAsync(erc20Proxy.address, new BigNumber(0), {
-                    from: makerAddress,
-                }),
-                constants.AWAIT_TRANSACTION_MINED_MS,
-            );
-            return expectRevertOrAlwaysFailingTransactionAsync(
-                exchangeWrapper.fillOrderAsync(signedOrder, takerAddress),
-            );
-        });
-
-        it('should throw if taker allowances are too low to fill order', async () => {
-            await web3Wrapper.awaitTransactionSuccessAsync(
-                await erc20TokenB.approve.sendTransactionAsync(erc20Proxy.address, new BigNumber(0), {
-                    from: takerAddress,
-                }),
-                constants.AWAIT_TRANSACTION_MINED_MS,
-            );
-            return expectRevertOrAlwaysFailingTransactionAsync(
-                exchangeWrapper.fillOrderAsync(signedOrder, takerAddress),
-            );
-        });
-
-        it('should throw if an order is expired', async () => {
-            signedOrder = orderFactory.newSignedOrder({
-                expirationTimeSeconds: new BigNumber(Math.floor((Date.now() - 10000) / 1000)),
-            });
-            return expectRevertOrAlwaysFailingTransactionAsync(
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
                 exchangeWrapper.fillOrderAsync(signedOrder, takerAddress),
+                RevertReason.InvalidOrderSignature,
             );
         });
 
         it('should throw if no value is filled', async () => {
             signedOrder = orderFactory.newSignedOrder();
             await exchangeWrapper.fillOrderAsync(signedOrder, takerAddress);
-            return expectRevertOrAlwaysFailingTransactionAsync(
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
                 exchangeWrapper.fillOrderAsync(signedOrder, takerAddress),
+                RevertReason.OrderUnfillable,
             );
         });
     });
@@ -535,8 +167,9 @@ describe('Exchange core', () => {
         });
 
         it('should throw if not sent by maker', async () => {
-            return expectRevertOrAlwaysFailingTransactionAsync(
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
                 exchangeWrapper.cancelOrderAsync(signedOrder, takerAddress),
+                RevertReason.InvalidMaker,
             );
         });
 
@@ -545,8 +178,9 @@ describe('Exchange core', () => {
                 makerAssetAmount: new BigNumber(0),
             });
 
-            return expectRevertOrAlwaysFailingTransactionAsync(
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
                 exchangeWrapper.cancelOrderAsync(signedOrder, makerAddress),
+                RevertReason.OrderUnfillable,
             );
         });
 
@@ -555,17 +189,19 @@ describe('Exchange core', () => {
                 takerAssetAmount: new BigNumber(0),
             });
 
-            return expectRevertOrAlwaysFailingTransactionAsync(
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
                 exchangeWrapper.cancelOrderAsync(signedOrder, makerAddress),
+                RevertReason.OrderUnfillable,
             );
         });
 
         it('should be able to cancel a full order', async () => {
             await exchangeWrapper.cancelOrderAsync(signedOrder, makerAddress);
-            return expectRevertOrAlwaysFailingTransactionAsync(
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
                 exchangeWrapper.fillOrderAsync(signedOrder, takerAddress, {
                     takerAssetFillAmount: signedOrder.takerAssetAmount.div(2),
                 }),
+                RevertReason.OrderUnfillable,
             );
         });
 
@@ -586,8 +222,9 @@ describe('Exchange core', () => {
 
         it('should throw if already cancelled', async () => {
             await exchangeWrapper.cancelOrderAsync(signedOrder, makerAddress);
-            return expectRevertOrAlwaysFailingTransactionAsync(
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
                 exchangeWrapper.cancelOrderAsync(signedOrder, makerAddress),
+                RevertReason.OrderUnfillable,
             );
         });
 
@@ -595,8 +232,9 @@ describe('Exchange core', () => {
             signedOrder = orderFactory.newSignedOrder({
                 expirationTimeSeconds: new BigNumber(Math.floor((Date.now() - 10000) / 1000)),
             });
-            return expectRevertOrAlwaysFailingTransactionAsync(
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
                 exchangeWrapper.cancelOrderAsync(signedOrder, makerAddress),
+                RevertReason.OrderUnfillable,
             );
         });
 
@@ -612,10 +250,11 @@ describe('Exchange core', () => {
             });
 
             const fillTakerAssetAmount2 = new BigNumber(1);
-            return expectRevertOrAlwaysFailingTransactionAsync(
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
                 exchangeWrapper.fillOrderAsync(signedOrder, takerAddress, {
                     takerAssetFillAmount: fillTakerAssetAmount2,
                 }),
+                RevertReason.RoundingError,
             );
         });
     });
@@ -625,16 +264,18 @@ describe('Exchange core', () => {
             const orderEpoch = new BigNumber(1);
             await exchangeWrapper.cancelOrdersUpToAsync(orderEpoch, makerAddress);
             const lesserOrderEpoch = new BigNumber(0);
-            return expectRevertOrAlwaysFailingTransactionAsync(
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
                 exchangeWrapper.cancelOrdersUpToAsync(lesserOrderEpoch, makerAddress),
+                RevertReason.InvalidNewOrderEpoch,
             );
         });
 
         it('should fail to set orderEpoch equal to existing orderEpoch', async () => {
             const orderEpoch = new BigNumber(1);
             await exchangeWrapper.cancelOrdersUpToAsync(orderEpoch, makerAddress);
-            return expectRevertOrAlwaysFailingTransactionAsync(
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
                 exchangeWrapper.cancelOrdersUpToAsync(orderEpoch, makerAddress),
+                RevertReason.InvalidNewOrderEpoch,
             );
         });
 
@@ -705,32 +346,6 @@ describe('Exchange core', () => {
     });
 
     describe('Testing Exchange of ERC721 Tokens', () => {
-        it('should successfully exchange a single token between the maker and taker (via fillOrder)', async () => {
-            // Construct Exchange parameters
-            const makerAssetId = erc721MakerAssetIds[0];
-            const takerAssetId = erc721TakerAssetIds[1];
-            signedOrder = orderFactory.newSignedOrder({
-                makerAssetAmount: new BigNumber(1),
-                takerAssetAmount: new BigNumber(1),
-                makerAssetData: assetProxyUtils.encodeERC721AssetData(erc721Token.address, makerAssetId),
-                takerAssetData: assetProxyUtils.encodeERC721AssetData(erc721Token.address, takerAssetId),
-            });
-            // Verify pre-conditions
-            const initialOwnerMakerAsset = await erc721Token.ownerOf.callAsync(makerAssetId);
-            expect(initialOwnerMakerAsset).to.be.bignumber.equal(makerAddress);
-            const initialOwnerTakerAsset = await erc721Token.ownerOf.callAsync(takerAssetId);
-            expect(initialOwnerTakerAsset).to.be.bignumber.equal(takerAddress);
-            // Call Exchange
-            const takerAssetFillAmount = signedOrder.takerAssetAmount;
-            // tslint:disable-next-line:no-unused-variable
-            const res = await exchangeWrapper.fillOrderAsync(signedOrder, takerAddress, { takerAssetFillAmount });
-            // Verify post-conditions
-            const newOwnerMakerAsset = await erc721Token.ownerOf.callAsync(makerAssetId);
-            expect(newOwnerMakerAsset).to.be.bignumber.equal(takerAddress);
-            const newOwnerTakerAsset = await erc721Token.ownerOf.callAsync(takerAssetId);
-            expect(newOwnerTakerAsset).to.be.bignumber.equal(makerAddress);
-        });
-
         it('should throw when maker does not own the token with id makerAssetId', async () => {
             // Construct Exchange parameters
             const makerAssetId = erc721TakerAssetIds[0];
@@ -748,8 +363,9 @@ describe('Exchange core', () => {
             expect(initialOwnerTakerAsset).to.be.bignumber.equal(takerAddress);
             // Call Exchange
             const takerAssetFillAmount = signedOrder.takerAssetAmount;
-            return expectRevertOrAlwaysFailingTransactionAsync(
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
                 exchangeWrapper.fillOrderAsync(signedOrder, takerAddress, { takerAssetFillAmount }),
+                RevertReason.TransferFailed,
             );
         });
 
@@ -770,8 +386,9 @@ describe('Exchange core', () => {
             expect(initialOwnerTakerAsset).to.be.bignumber.not.equal(takerAddress);
             // Call Exchange
             const takerAssetFillAmount = signedOrder.takerAssetAmount;
-            return expectRevertOrAlwaysFailingTransactionAsync(
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
                 exchangeWrapper.fillOrderAsync(signedOrder, takerAddress, { takerAssetFillAmount }),
+                RevertReason.TransferFailed,
             );
         });
 
@@ -792,8 +409,9 @@ describe('Exchange core', () => {
             expect(initialOwnerTakerAsset).to.be.bignumber.equal(takerAddress);
             // Call Exchange
             const takerAssetFillAmount = signedOrder.takerAssetAmount;
-            return expectRevertOrAlwaysFailingTransactionAsync(
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
                 exchangeWrapper.fillOrderAsync(signedOrder, takerAddress, { takerAssetFillAmount }),
+                RevertReason.InvalidAmount,
             );
         });
 
@@ -814,110 +432,52 @@ describe('Exchange core', () => {
             expect(initialOwnerTakerAsset).to.be.bignumber.equal(takerAddress);
             // Call Exchange
             const takerAssetFillAmount = signedOrder.takerAssetAmount;
-            return expectRevertOrAlwaysFailingTransactionAsync(
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
                 exchangeWrapper.fillOrderAsync(signedOrder, takerAddress, { takerAssetFillAmount }),
+                RevertReason.InvalidAmount,
             );
         });
 
         it('should throw on partial fill', async () => {
             // Construct Exchange parameters
             const makerAssetId = erc721MakerAssetIds[0];
-            const takerAssetId = erc721TakerAssetIds[0];
-            signedOrder = orderFactory.newSignedOrder({
-                makerAssetAmount: new BigNumber(1),
-                takerAssetAmount: new BigNumber(0),
-                makerAssetData: assetProxyUtils.encodeERC721AssetData(erc721Token.address, makerAssetId),
-                takerAssetData: assetProxyUtils.encodeERC721AssetData(erc721Token.address, takerAssetId),
-            });
-            // Verify pre-conditions
-            const initialOwnerMakerAsset = await erc721Token.ownerOf.callAsync(makerAssetId);
-            expect(initialOwnerMakerAsset).to.be.bignumber.equal(makerAddress);
-            const initialOwnerTakerAsset = await erc721Token.ownerOf.callAsync(takerAssetId);
-            expect(initialOwnerTakerAsset).to.be.bignumber.equal(takerAddress);
-            // Call Exchange
-            const takerAssetFillAmount = signedOrder.takerAssetAmount;
-            return expectRevertOrAlwaysFailingTransactionAsync(
-                exchangeWrapper.fillOrderAsync(signedOrder, takerAddress, { takerAssetFillAmount }),
-            );
-        });
-
-        it('should successfully fill order when makerAsset is ERC721 and takerAsset is ERC20', async () => {
-            // Construct Exchange parameters
-            const makerAssetId = erc721MakerAssetIds[0];
             signedOrder = orderFactory.newSignedOrder({
                 makerAssetAmount: new BigNumber(1),
                 takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(100), 18),
                 makerAssetData: assetProxyUtils.encodeERC721AssetData(erc721Token.address, makerAssetId),
                 takerAssetData: assetProxyUtils.encodeERC20AssetData(defaultTakerAssetAddress),
             });
-            // Verify pre-conditions
-            const initialOwnerMakerAsset = await erc721Token.ownerOf.callAsync(makerAssetId);
-            expect(initialOwnerMakerAsset).to.be.bignumber.equal(makerAddress);
             // Call Exchange
-            erc20Balances = await erc20Wrapper.getBalancesAsync();
-            const takerAssetFillAmount = signedOrder.takerAssetAmount;
-            await exchangeWrapper.fillOrderAsync(signedOrder, takerAddress, { takerAssetFillAmount });
-            // Verify ERC721 token was transferred from Maker to Taker
-            const newOwnerMakerAsset = await erc721Token.ownerOf.callAsync(makerAssetId);
-            expect(newOwnerMakerAsset).to.be.bignumber.equal(takerAddress);
-            // Verify ERC20 tokens were transferred from Taker to Maker & fees were paid correctly
-            const newBalances = await erc20Wrapper.getBalancesAsync();
-            expect(newBalances[makerAddress][defaultTakerAssetAddress]).to.be.bignumber.equal(
-                erc20Balances[makerAddress][defaultTakerAssetAddress].add(takerAssetFillAmount),
-            );
-            expect(newBalances[takerAddress][defaultTakerAssetAddress]).to.be.bignumber.equal(
-                erc20Balances[takerAddress][defaultTakerAssetAddress].minus(takerAssetFillAmount),
-            );
-            expect(newBalances[makerAddress][zrxToken.address]).to.be.bignumber.equal(
-                erc20Balances[makerAddress][zrxToken.address].minus(signedOrder.makerFee),
-            );
-            expect(newBalances[takerAddress][zrxToken.address]).to.be.bignumber.equal(
-                erc20Balances[takerAddress][zrxToken.address].minus(signedOrder.takerFee),
-            );
-            expect(newBalances[feeRecipientAddress][zrxToken.address]).to.be.bignumber.equal(
-                erc20Balances[feeRecipientAddress][zrxToken.address].add(
-                    signedOrder.makerFee.add(signedOrder.takerFee),
-                ),
+            const takerAssetFillAmount = signedOrder.takerAssetAmount.div(2);
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
+                exchangeWrapper.fillOrderAsync(signedOrder, takerAddress, { takerAssetFillAmount }),
+                RevertReason.RoundingError,
             );
         });
 
-        it('should successfully fill order when makerAsset is ERC20 and takerAsset is ERC721', async () => {
+        it('should throw if assetData has a length < 132', async () => {
             // Construct Exchange parameters
+            const makerAssetId = erc721MakerAssetIds[0];
             const takerAssetId = erc721TakerAssetIds[0];
+            const makerAssetData = assetProxyUtils
+                .encodeERC721AssetData(erc721Token.address, makerAssetId)
+                .slice(0, -2);
             signedOrder = orderFactory.newSignedOrder({
+                makerAssetAmount: new BigNumber(1),
                 takerAssetAmount: new BigNumber(1),
-                makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(100), 18),
+                makerAssetData,
                 takerAssetData: assetProxyUtils.encodeERC721AssetData(erc721Token.address, takerAssetId),
-                makerAssetData: assetProxyUtils.encodeERC20AssetData(defaultMakerAssetAddress),
             });
             // Verify pre-conditions
+            const initialOwnerMakerAsset = await erc721Token.ownerOf.callAsync(makerAssetId);
+            expect(initialOwnerMakerAsset).to.be.bignumber.equal(makerAddress);
             const initialOwnerTakerAsset = await erc721Token.ownerOf.callAsync(takerAssetId);
             expect(initialOwnerTakerAsset).to.be.bignumber.equal(takerAddress);
             // Call Exchange
-            erc20Balances = await erc20Wrapper.getBalancesAsync();
             const takerAssetFillAmount = signedOrder.takerAssetAmount;
-            await exchangeWrapper.fillOrderAsync(signedOrder, takerAddress, { takerAssetFillAmount });
-            // Verify ERC721 token was transferred from Taker to Maker
-            const newOwnerTakerAsset = await erc721Token.ownerOf.callAsync(takerAssetId);
-            expect(newOwnerTakerAsset).to.be.bignumber.equal(makerAddress);
-            // Verify ERC20 tokens were transferred from Maker to Taker & fees were paid correctly
-            const newBalances = await erc20Wrapper.getBalancesAsync();
-            expect(newBalances[takerAddress][defaultMakerAssetAddress]).to.be.bignumber.equal(
-                erc20Balances[takerAddress][defaultMakerAssetAddress].add(signedOrder.makerAssetAmount),
-            );
-            expect(newBalances[makerAddress][defaultMakerAssetAddress]).to.be.bignumber.equal(
-                erc20Balances[makerAddress][defaultMakerAssetAddress].minus(signedOrder.makerAssetAmount),
-            );
-            expect(newBalances[makerAddress][zrxToken.address]).to.be.bignumber.equal(
-                erc20Balances[makerAddress][zrxToken.address].minus(signedOrder.makerFee),
-            );
-            expect(newBalances[takerAddress][zrxToken.address]).to.be.bignumber.equal(
-                erc20Balances[takerAddress][zrxToken.address].minus(signedOrder.takerFee),
-            );
-            expect(newBalances[feeRecipientAddress][zrxToken.address]).to.be.bignumber.equal(
-                erc20Balances[feeRecipientAddress][zrxToken.address].add(
-                    signedOrder.makerFee.add(signedOrder.takerFee),
-                ),
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
+                exchangeWrapper.fillOrderAsync(signedOrder, takerAddress, { takerAssetFillAmount }),
+                RevertReason.LengthGreaterThan131Required,
             );
         });
     });
diff --git a/packages/contracts/test/exchange/dispatcher.ts b/packages/contracts/test/exchange/dispatcher.ts
index abbfd7ac7..afbf958d9 100644
--- a/packages/contracts/test/exchange/dispatcher.ts
+++ b/packages/contracts/test/exchange/dispatcher.ts
@@ -1,25 +1,31 @@
 import { BlockchainLifecycle } from '@0xproject/dev-utils';
 import { assetProxyUtils } from '@0xproject/order-utils';
-import { AssetProxyId } from '@0xproject/types';
+import { AssetProxyId, RevertReason } from '@0xproject/types';
 import { BigNumber } from '@0xproject/utils';
 import * as chai from 'chai';
-
-import { DummyERC20TokenContract } from '../../src/generated_contract_wrappers/dummy_e_r_c20_token';
-import { ERC20ProxyContract } from '../../src/generated_contract_wrappers/e_r_c20_proxy';
-import { ERC721ProxyContract } from '../../src/generated_contract_wrappers/e_r_c721_proxy';
-import { TestAssetProxyDispatcherContract } from '../../src/generated_contract_wrappers/test_asset_proxy_dispatcher';
-import { artifacts } from '../../src/utils/artifacts';
-import { expectRevertOrAlwaysFailingTransactionAsync } from '../../src/utils/assertions';
-import { chaiSetup } from '../../src/utils/chai_setup';
-import { constants } from '../../src/utils/constants';
-import { ERC20Wrapper } from '../../src/utils/erc20_wrapper';
-import { ERC721Wrapper } from '../../src/utils/erc721_wrapper';
-import { provider, txDefaults, web3Wrapper } from '../../src/utils/web3_wrapper';
+import { LogWithDecodedArgs } from 'ethereum-types';
+import * as _ from 'lodash';
+
+import { DummyERC20TokenContract } from '../../generated_contract_wrappers/dummy_e_r_c20_token';
+import { ERC20ProxyContract } from '../../generated_contract_wrappers/e_r_c20_proxy';
+import { ERC721ProxyContract } from '../../generated_contract_wrappers/e_r_c721_proxy';
+import {
+    AssetProxyRegisteredContractEventArgs,
+    TestAssetProxyDispatcherContract,
+} from '../../generated_contract_wrappers/test_asset_proxy_dispatcher';
+import { artifacts } from '../utils/artifacts';
+import { expectRevertReasonOrAlwaysFailingTransactionAsync } from '../utils/assertions';
+import { chaiSetup } from '../utils/chai_setup';
+import { constants } from '../utils/constants';
+import { ERC20Wrapper } from '../utils/erc20_wrapper';
+import { ERC721Wrapper } from '../utils/erc721_wrapper';
+import { LogDecoder } from '../utils/log_decoder';
+import { provider, txDefaults, web3Wrapper } from '../utils/web3_wrapper';
 
 chaiSetup.configure();
 const expect = chai.expect;
 const blockchainLifecycle = new BlockchainLifecycle(web3Wrapper);
-
+// tslint:disable:no-unnecessary-type-assertion
 describe('AssetProxyDispatcher', () => {
     let owner: string;
     let notOwner: string;
@@ -43,12 +49,13 @@ describe('AssetProxyDispatcher', () => {
     before(async () => {
         // Setup accounts & addresses
         const accounts = await web3Wrapper.getAvailableAddressesAsync();
-        const usedAddresses = ([owner, notOwner, makerAddress, takerAddress] = accounts);
+        const usedAddresses = ([owner, notOwner, makerAddress, takerAddress] = _.slice(accounts, 0, 4));
 
         erc20Wrapper = new ERC20Wrapper(provider, usedAddresses, owner);
         erc721Wrapper = new ERC721Wrapper(provider, usedAddresses, owner);
 
-        [zrxToken] = await erc20Wrapper.deployDummyTokensAsync();
+        const numDummyErc20ToDeploy = 1;
+        [zrxToken] = await erc20Wrapper.deployDummyTokensAsync(numDummyErc20ToDeploy, constants.DUMMY_TOKEN_DECIMALS);
         erc20Proxy = await erc20Wrapper.deployProxyAsync();
         await erc20Wrapper.setBalancesAndAllowancesAsync();
 
@@ -80,14 +87,8 @@ describe('AssetProxyDispatcher', () => {
     });
     describe('registerAssetProxy', () => {
         it('should record proxy upon registration', async () => {
-            const prevProxyAddress = constants.NULL_ADDRESS;
             await web3Wrapper.awaitTransactionSuccessAsync(
-                await assetProxyDispatcher.registerAssetProxy.sendTransactionAsync(
-                    AssetProxyId.ERC20,
-                    erc20Proxy.address,
-                    prevProxyAddress,
-                    { from: owner },
-                ),
+                await assetProxyDispatcher.registerAssetProxy.sendTransactionAsync(erc20Proxy.address, { from: owner }),
                 constants.AWAIT_TRANSACTION_MINED_MS,
             );
             const proxyAddress = await assetProxyDispatcher.getAssetProxy.callAsync(AssetProxyId.ERC20);
@@ -96,46 +97,30 @@ describe('AssetProxyDispatcher', () => {
 
         it('should be able to record multiple proxies', async () => {
             // Record first proxy
-            const prevERC20ProxyAddress = constants.NULL_ADDRESS;
             await web3Wrapper.awaitTransactionSuccessAsync(
-                await assetProxyDispatcher.registerAssetProxy.sendTransactionAsync(
-                    AssetProxyId.ERC20,
-                    erc20Proxy.address,
-                    prevERC20ProxyAddress,
-                    { from: owner },
-                ),
+                await assetProxyDispatcher.registerAssetProxy.sendTransactionAsync(erc20Proxy.address, { from: owner }),
                 constants.AWAIT_TRANSACTION_MINED_MS,
             );
             let proxyAddress = await assetProxyDispatcher.getAssetProxy.callAsync(AssetProxyId.ERC20);
             expect(proxyAddress).to.be.equal(erc20Proxy.address);
             // Record another proxy
-            const prevERC721ProxyAddress = constants.NULL_ADDRESS;
             await web3Wrapper.awaitTransactionSuccessAsync(
-                await assetProxyDispatcher.registerAssetProxy.sendTransactionAsync(
-                    AssetProxyId.ERC721,
-                    erc721Proxy.address,
-                    prevERC721ProxyAddress,
-                    { from: owner },
-                ),
+                await assetProxyDispatcher.registerAssetProxy.sendTransactionAsync(erc721Proxy.address, {
+                    from: owner,
+                }),
                 constants.AWAIT_TRANSACTION_MINED_MS,
             );
             proxyAddress = await assetProxyDispatcher.getAssetProxy.callAsync(AssetProxyId.ERC721);
             expect(proxyAddress).to.be.equal(erc721Proxy.address);
         });
 
-        it('should replace proxy address upon re-registration', async () => {
+        it('should throw if a proxy with the same id is already registered', async () => {
             // Initial registration
-            const prevProxyAddress = constants.NULL_ADDRESS;
             await web3Wrapper.awaitTransactionSuccessAsync(
-                await assetProxyDispatcher.registerAssetProxy.sendTransactionAsync(
-                    AssetProxyId.ERC20,
-                    erc20Proxy.address,
-                    prevProxyAddress,
-                    { from: owner },
-                ),
+                await assetProxyDispatcher.registerAssetProxy.sendTransactionAsync(erc20Proxy.address, { from: owner }),
                 constants.AWAIT_TRANSACTION_MINED_MS,
             );
-            let proxyAddress = await assetProxyDispatcher.getAssetProxy.callAsync(AssetProxyId.ERC20);
+            const proxyAddress = await assetProxyDispatcher.getAssetProxy.callAsync(AssetProxyId.ERC20);
             expect(proxyAddress).to.be.equal(erc20Proxy.address);
             // Deploy a new version of the ERC20 Transfer Proxy contract
             const newErc20TransferProxy = await ERC20ProxyContract.deployFrom0xArtifactAsync(
@@ -144,111 +129,37 @@ describe('AssetProxyDispatcher', () => {
                 txDefaults,
             );
             // Register new ERC20 Transfer Proxy contract
-            const newAddress = newErc20TransferProxy.address;
-            const currentAddress = erc20Proxy.address;
-            await web3Wrapper.awaitTransactionSuccessAsync(
-                await assetProxyDispatcher.registerAssetProxy.sendTransactionAsync(
-                    AssetProxyId.ERC20,
-                    newAddress,
-                    currentAddress,
-                    { from: owner },
-                ),
-                constants.AWAIT_TRANSACTION_MINED_MS,
-            );
-            // Verify new asset proxy has replaced initial version
-            proxyAddress = await assetProxyDispatcher.getAssetProxy.callAsync(AssetProxyId.ERC20);
-            expect(proxyAddress).to.be.equal(newAddress);
-        });
-
-        it('should throw if registering with incorrect "currentAssetProxyAddress" field', async () => {
-            // Initial registration
-            const prevProxyAddress = constants.NULL_ADDRESS;
-            await web3Wrapper.awaitTransactionSuccessAsync(
-                await assetProxyDispatcher.registerAssetProxy.sendTransactionAsync(
-                    AssetProxyId.ERC20,
-                    erc20Proxy.address,
-                    prevProxyAddress,
-                    { from: owner },
-                ),
-                constants.AWAIT_TRANSACTION_MINED_MS,
-            );
-            const proxyAddress = await assetProxyDispatcher.getAssetProxy.callAsync(AssetProxyId.ERC20);
-            expect(proxyAddress).to.be.equal(erc20Proxy.address);
-            // The following transaction will throw because the currentAddress is no longer constants.NULL_ADDRESS
-            return expectRevertOrAlwaysFailingTransactionAsync(
-                assetProxyDispatcher.registerAssetProxy.sendTransactionAsync(
-                    AssetProxyId.ERC20,
-                    erc20Proxy.address,
-                    constants.NULL_ADDRESS,
-                    { from: owner },
-                ),
-            );
-        });
-
-        it('should be able to reset proxy address to NULL', async () => {
-            // Initial registration
-            const prevProxyAddress = constants.NULL_ADDRESS;
-            await web3Wrapper.awaitTransactionSuccessAsync(
-                await assetProxyDispatcher.registerAssetProxy.sendTransactionAsync(
-                    AssetProxyId.ERC20,
-                    erc20Proxy.address,
-                    prevProxyAddress,
-                    { from: owner },
-                ),
-                constants.AWAIT_TRANSACTION_MINED_MS,
-            );
-            const proxyAddress = await assetProxyDispatcher.getAssetProxy.callAsync(AssetProxyId.ERC20);
-            expect(proxyAddress).to.be.equal(erc20Proxy.address);
-            // The following transaction will reset the proxy address
-            const newProxyAddress = constants.NULL_ADDRESS;
-            await web3Wrapper.awaitTransactionSuccessAsync(
-                await assetProxyDispatcher.registerAssetProxy.sendTransactionAsync(
-                    AssetProxyId.ERC20,
-                    newProxyAddress,
-                    erc20Proxy.address,
-                    { from: owner },
-                ),
-                constants.AWAIT_TRANSACTION_MINED_MS,
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
+                assetProxyDispatcher.registerAssetProxy.sendTransactionAsync(newErc20TransferProxy.address, {
+                    from: owner,
+                }),
+                RevertReason.AssetProxyAlreadyExists,
             );
-            const finalProxyAddress = await assetProxyDispatcher.getAssetProxy.callAsync(AssetProxyId.ERC20);
-            expect(finalProxyAddress).to.be.equal(newProxyAddress);
         });
 
         it('should throw if requesting address is not owner', async () => {
-            const prevProxyAddress = constants.NULL_ADDRESS;
-            return expectRevertOrAlwaysFailingTransactionAsync(
-                assetProxyDispatcher.registerAssetProxy.sendTransactionAsync(
-                    AssetProxyId.ERC20,
-                    erc20Proxy.address,
-                    prevProxyAddress,
-                    { from: notOwner },
-                ),
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
+                assetProxyDispatcher.registerAssetProxy.sendTransactionAsync(erc20Proxy.address, { from: notOwner }),
+                RevertReason.OnlyContractOwner,
             );
         });
 
-        it('should throw if attempting to register a proxy to the incorrect id', async () => {
-            const prevProxyAddress = constants.NULL_ADDRESS;
-            return expectRevertOrAlwaysFailingTransactionAsync(
-                assetProxyDispatcher.registerAssetProxy.sendTransactionAsync(
-                    AssetProxyId.ERC721,
-                    erc20Proxy.address,
-                    prevProxyAddress,
-                    { from: owner },
-                ),
+        it('should log an event with correct arguments when an asset proxy is registered', async () => {
+            const logDecoder = new LogDecoder(web3Wrapper, assetProxyDispatcher.address);
+            const txReceipt = await logDecoder.getTxWithDecodedLogsAsync(
+                await assetProxyDispatcher.registerAssetProxy.sendTransactionAsync(erc20Proxy.address, { from: owner }),
             );
+            const logs = txReceipt.logs;
+            const log = logs[0] as LogWithDecodedArgs<AssetProxyRegisteredContractEventArgs>;
+            expect(log.args.id).to.equal(AssetProxyId.ERC20);
+            expect(log.args.assetProxy).to.equal(erc20Proxy.address);
         });
     });
 
     describe('getAssetProxy', () => {
         it('should return correct address of registered proxy', async () => {
-            const prevProxyAddress = constants.NULL_ADDRESS;
             await web3Wrapper.awaitTransactionSuccessAsync(
-                await assetProxyDispatcher.registerAssetProxy.sendTransactionAsync(
-                    AssetProxyId.ERC20,
-                    erc20Proxy.address,
-                    prevProxyAddress,
-                    { from: owner },
-                ),
+                await assetProxyDispatcher.registerAssetProxy.sendTransactionAsync(erc20Proxy.address, { from: owner }),
                 constants.AWAIT_TRANSACTION_MINED_MS,
             );
             const proxyAddress = await assetProxyDispatcher.getAssetProxy.callAsync(AssetProxyId.ERC20);
@@ -264,26 +175,19 @@ describe('AssetProxyDispatcher', () => {
     describe('dispatchTransferFrom', () => {
         it('should dispatch transfer to registered proxy', async () => {
             // Register ERC20 proxy
-            const prevProxyAddress = constants.NULL_ADDRESS;
             await web3Wrapper.awaitTransactionSuccessAsync(
-                await assetProxyDispatcher.registerAssetProxy.sendTransactionAsync(
-                    AssetProxyId.ERC20,
-                    erc20Proxy.address,
-                    prevProxyAddress,
-                    { from: owner },
-                ),
+                await assetProxyDispatcher.registerAssetProxy.sendTransactionAsync(erc20Proxy.address, { from: owner }),
                 constants.AWAIT_TRANSACTION_MINED_MS,
             );
             // Construct metadata for ERC20 proxy
             const encodedAssetData = assetProxyUtils.encodeERC20AssetData(zrxToken.address);
-            const encodedAssetDataWithoutProxyId = encodedAssetData.slice(0, -2);
+
             // Perform a transfer from makerAddress to takerAddress
             const erc20Balances = await erc20Wrapper.getBalancesAsync();
             const amount = new BigNumber(10);
             await web3Wrapper.awaitTransactionSuccessAsync(
                 await assetProxyDispatcher.publicDispatchTransferFrom.sendTransactionAsync(
-                    encodedAssetDataWithoutProxyId,
-                    AssetProxyId.ERC20,
+                    encodedAssetData,
                     makerAddress,
                     takerAddress,
                     amount,
@@ -304,19 +208,19 @@ describe('AssetProxyDispatcher', () => {
         it('should throw if dispatching to unregistered proxy', async () => {
             // Construct metadata for ERC20 proxy
             const encodedAssetData = assetProxyUtils.encodeERC20AssetData(zrxToken.address);
-            const encodedAssetDataWithoutProxyId = encodedAssetData.slice(0, -2);
             // Perform a transfer from makerAddress to takerAddress
             const amount = new BigNumber(10);
-            return expectRevertOrAlwaysFailingTransactionAsync(
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
                 assetProxyDispatcher.publicDispatchTransferFrom.sendTransactionAsync(
-                    encodedAssetDataWithoutProxyId,
-                    AssetProxyId.ERC20,
+                    encodedAssetData,
                     makerAddress,
                     takerAddress,
                     amount,
                     { from: owner },
                 ),
+                RevertReason.AssetProxyDoesNotExist,
             );
         });
     });
 });
+// tslint:enable:no-unnecessary-type-assertion
diff --git a/packages/contracts/test/exchange/fill_order.ts b/packages/contracts/test/exchange/fill_order.ts
new file mode 100644
index 000000000..22eb401d9
--- /dev/null
+++ b/packages/contracts/test/exchange/fill_order.ts
@@ -0,0 +1,305 @@
+import { BlockchainLifecycle } from '@0xproject/dev-utils';
+import * as _ from 'lodash';
+
+import { chaiSetup } from '../utils/chai_setup';
+import { CoreCombinatorialUtils, coreCombinatorialUtilsFactoryAsync } from '../utils/core_combinatorial_utils';
+import {
+    AllowanceAmountScenario,
+    AssetDataScenario,
+    BalanceAmountScenario,
+    ExpirationTimeSecondsScenario,
+    FeeRecipientAddressScenario,
+    FillScenario,
+    OrderAssetAmountScenario,
+    TakerAssetFillAmountScenario,
+    TakerScenario,
+} from '../utils/types';
+import { provider, txDefaults, web3Wrapper } from '../utils/web3_wrapper';
+
+chaiSetup.configure();
+const blockchainLifecycle = new BlockchainLifecycle(web3Wrapper);
+
+const defaultFillScenario = {
+    orderScenario: {
+        takerScenario: TakerScenario.Unspecified,
+        feeRecipientScenario: FeeRecipientAddressScenario.EthUserAddress,
+        makerAssetAmountScenario: OrderAssetAmountScenario.Large,
+        takerAssetAmountScenario: OrderAssetAmountScenario.Large,
+        makerFeeScenario: OrderAssetAmountScenario.Large,
+        takerFeeScenario: OrderAssetAmountScenario.Large,
+        expirationTimeSecondsScenario: ExpirationTimeSecondsScenario.InFuture,
+        makerAssetDataScenario: AssetDataScenario.ERC20NonZRXEighteenDecimals,
+        takerAssetDataScenario: AssetDataScenario.ERC20NonZRXEighteenDecimals,
+    },
+    takerAssetFillAmountScenario: TakerAssetFillAmountScenario.LessThanRemainingFillableTakerAssetAmount,
+    makerStateScenario: {
+        traderAssetBalance: BalanceAmountScenario.Higher,
+        traderAssetAllowance: AllowanceAmountScenario.Higher,
+        zrxFeeBalance: BalanceAmountScenario.Higher,
+        zrxFeeAllowance: AllowanceAmountScenario.Higher,
+    },
+    takerStateScenario: {
+        traderAssetBalance: BalanceAmountScenario.Higher,
+        traderAssetAllowance: AllowanceAmountScenario.Higher,
+        zrxFeeBalance: BalanceAmountScenario.Higher,
+        zrxFeeAllowance: AllowanceAmountScenario.Higher,
+    },
+};
+
+describe('FillOrder Tests', () => {
+    let coreCombinatorialUtils: CoreCombinatorialUtils;
+
+    before(async () => {
+        await blockchainLifecycle.startAsync();
+        coreCombinatorialUtils = await coreCombinatorialUtilsFactoryAsync(web3Wrapper, txDefaults);
+    });
+    after(async () => {
+        await blockchainLifecycle.revertAsync();
+    });
+    beforeEach(async () => {
+        await blockchainLifecycle.startAsync();
+    });
+    afterEach(async () => {
+        await blockchainLifecycle.revertAsync();
+    });
+    describe('fillOrder', () => {
+        const test = (fillScenarios: FillScenario[]) => {
+            _.forEach(fillScenarios, fillScenario => {
+                const orderScenario = fillScenario.orderScenario;
+                const description = `Combinatorial OrderFill: ${orderScenario.feeRecipientScenario} ${
+                    orderScenario.makerAssetAmountScenario
+                } ${orderScenario.takerAssetAmountScenario} ${orderScenario.makerFeeScenario} ${
+                    orderScenario.takerFeeScenario
+                } ${orderScenario.expirationTimeSecondsScenario} ${orderScenario.makerAssetDataScenario} ${
+                    orderScenario.takerAssetDataScenario
+                }`;
+                it(description, async () => {
+                    await coreCombinatorialUtils.testFillOrderScenarioAsync(provider, fillScenario);
+                });
+            });
+        };
+
+        const allFillScenarios = CoreCombinatorialUtils.generateFillOrderCombinations();
+        describe('Combinatorially generated fills orders', () => test(allFillScenarios));
+
+        it('should transfer the correct amounts when makerAssetAmount === takerAssetAmount', async () => {
+            const fillScenario = {
+                ...defaultFillScenario,
+            };
+            await coreCombinatorialUtils.testFillOrderScenarioAsync(provider, fillScenario);
+        });
+        it('should transfer the correct amounts when makerAssetAmount > takerAssetAmount', async () => {
+            const fillScenario = {
+                ...defaultFillScenario,
+                orderScenario: {
+                    ...defaultFillScenario.orderScenario,
+                    takerAssetAmountScenario: OrderAssetAmountScenario.Small,
+                },
+            };
+            await coreCombinatorialUtils.testFillOrderScenarioAsync(provider, fillScenario);
+        });
+        it('should transfer the correct amounts when makerAssetAmount < takerAssetAmount', async () => {
+            const fillScenario = {
+                ...defaultFillScenario,
+                orderScenario: {
+                    ...defaultFillScenario.orderScenario,
+                    makerAssetAmountScenario: OrderAssetAmountScenario.Small,
+                },
+            };
+            await coreCombinatorialUtils.testFillOrderScenarioAsync(provider, fillScenario);
+        });
+        it('should transfer the correct amounts when taker is specified and order is claimed by taker', async () => {
+            const fillScenario = {
+                ...defaultFillScenario,
+                orderScenario: {
+                    ...defaultFillScenario.orderScenario,
+                    takerScenario: TakerScenario.CorrectlySpecified,
+                },
+            };
+            await coreCombinatorialUtils.testFillOrderScenarioAsync(provider, fillScenario);
+        });
+        it('should fill remaining value if takerAssetFillAmount > remaining takerAssetAmount', async () => {
+            const fillScenario = {
+                ...defaultFillScenario,
+                takerAssetFillAmountScenario: TakerAssetFillAmountScenario.GreaterThanRemainingFillableTakerAssetAmount,
+            };
+            await coreCombinatorialUtils.testFillOrderScenarioAsync(provider, fillScenario);
+        });
+        it('should throw when taker is specified and order is claimed by other', async () => {
+            const fillScenario = {
+                ...defaultFillScenario,
+                orderScenario: {
+                    ...defaultFillScenario.orderScenario,
+                    takerScenario: TakerScenario.IncorrectlySpecified,
+                },
+            };
+            await coreCombinatorialUtils.testFillOrderScenarioAsync(provider, fillScenario);
+        });
+
+        it('should throw if makerAssetAmount is 0', async () => {
+            const fillScenario = {
+                ...defaultFillScenario,
+                orderScenario: {
+                    ...defaultFillScenario.orderScenario,
+                    makerAssetAmountScenario: OrderAssetAmountScenario.Zero,
+                },
+                takerAssetFillAmountScenario: TakerAssetFillAmountScenario.GreaterThanRemainingFillableTakerAssetAmount,
+            };
+            await coreCombinatorialUtils.testFillOrderScenarioAsync(provider, fillScenario);
+        });
+
+        it('should throw if takerAssetAmount is 0', async () => {
+            const fillScenario = {
+                ...defaultFillScenario,
+                orderScenario: {
+                    ...defaultFillScenario.orderScenario,
+                    takerAssetAmountScenario: OrderAssetAmountScenario.Zero,
+                },
+                takerAssetFillAmountScenario: TakerAssetFillAmountScenario.GreaterThanRemainingFillableTakerAssetAmount,
+            };
+            await coreCombinatorialUtils.testFillOrderScenarioAsync(provider, fillScenario);
+        });
+
+        it('should throw if takerAssetFillAmount is 0', async () => {
+            const fillScenario = {
+                ...defaultFillScenario,
+                takerAssetFillAmountScenario: TakerAssetFillAmountScenario.Zero,
+            };
+            await coreCombinatorialUtils.testFillOrderScenarioAsync(provider, fillScenario);
+        });
+
+        it('should throw if an order is expired', async () => {
+            const fillScenario = {
+                ...defaultFillScenario,
+                orderScenario: {
+                    ...defaultFillScenario.orderScenario,
+                    expirationTimeSecondsScenario: ExpirationTimeSecondsScenario.InPast,
+                },
+            };
+            await coreCombinatorialUtils.testFillOrderScenarioAsync(provider, fillScenario);
+        });
+
+        it('should throw if maker erc20Balances are too low to fill order', async () => {
+            const fillScenario = {
+                ...defaultFillScenario,
+                makerStateScenario: {
+                    ...defaultFillScenario.makerStateScenario,
+                    traderAssetBalance: BalanceAmountScenario.TooLow,
+                },
+            };
+            await coreCombinatorialUtils.testFillOrderScenarioAsync(provider, fillScenario);
+        });
+
+        it('should throw if taker erc20Balances are too low to fill order', async () => {
+            const fillScenario = {
+                ...defaultFillScenario,
+                takerStateScenario: {
+                    ...defaultFillScenario.makerStateScenario,
+                    traderAssetBalance: BalanceAmountScenario.TooLow,
+                },
+            };
+            await coreCombinatorialUtils.testFillOrderScenarioAsync(provider, fillScenario);
+        });
+
+        it('should throw if maker allowances are too low to fill order', async () => {
+            const fillScenario = {
+                ...defaultFillScenario,
+                makerStateScenario: {
+                    ...defaultFillScenario.makerStateScenario,
+                    traderAssetAllowance: AllowanceAmountScenario.TooLow,
+                },
+            };
+            await coreCombinatorialUtils.testFillOrderScenarioAsync(provider, fillScenario);
+        });
+
+        it('should throw if taker allowances are too low to fill order', async () => {
+            const fillScenario = {
+                ...defaultFillScenario,
+                takerStateScenario: {
+                    ...defaultFillScenario.makerStateScenario,
+                    traderAssetAllowance: AllowanceAmountScenario.TooLow,
+                },
+            };
+            await coreCombinatorialUtils.testFillOrderScenarioAsync(provider, fillScenario);
+        });
+    });
+
+    describe('Testing Exchange of ERC721 Tokens', () => {
+        it('should successfully exchange a single token between the maker and taker (via fillOrder)', async () => {
+            const fillScenario = {
+                ...defaultFillScenario,
+                orderScenario: {
+                    ...defaultFillScenario.orderScenario,
+                    makerAssetDataScenario: AssetDataScenario.ERC721,
+                    takerAssetDataScenario: AssetDataScenario.ERC721,
+                },
+                takerAssetFillAmountScenario: TakerAssetFillAmountScenario.ExactlyRemainingFillableTakerAssetAmount,
+            };
+            await coreCombinatorialUtils.testFillOrderScenarioAsync(provider, fillScenario);
+        });
+
+        it('should successfully fill order when makerAsset is ERC721 and takerAsset is ERC20', async () => {
+            const fillScenario = {
+                ...defaultFillScenario,
+                orderScenario: {
+                    ...defaultFillScenario.orderScenario,
+                    makerAssetDataScenario: AssetDataScenario.ERC721,
+                    takerAssetDataScenario: AssetDataScenario.ERC20NonZRXEighteenDecimals,
+                },
+                takerAssetFillAmountScenario: TakerAssetFillAmountScenario.ExactlyRemainingFillableTakerAssetAmount,
+            };
+            await coreCombinatorialUtils.testFillOrderScenarioAsync(provider, fillScenario, true);
+        });
+
+        it('should successfully fill order when makerAsset is ERC20 and takerAsset is ERC721', async () => {
+            const fillScenario = {
+                ...defaultFillScenario,
+                orderScenario: {
+                    ...defaultFillScenario.orderScenario,
+                    makerAssetDataScenario: AssetDataScenario.ERC20NonZRXEighteenDecimals,
+                    takerAssetDataScenario: AssetDataScenario.ERC721,
+                },
+                takerAssetFillAmountScenario: TakerAssetFillAmountScenario.ExactlyRemainingFillableTakerAssetAmount,
+            };
+            await coreCombinatorialUtils.testFillOrderScenarioAsync(provider, fillScenario);
+        });
+
+        it('should successfully fill order when makerAsset is ERC721 and approveAll is set for it', async () => {
+            const fillScenario = {
+                ...defaultFillScenario,
+                orderScenario: {
+                    ...defaultFillScenario.orderScenario,
+                    makerAssetDataScenario: AssetDataScenario.ERC721,
+                    takerAssetDataScenario: AssetDataScenario.ERC20NonZRXEighteenDecimals,
+                },
+                takerAssetFillAmountScenario: TakerAssetFillAmountScenario.ExactlyRemainingFillableTakerAssetAmount,
+                makerStateScenario: {
+                    ...defaultFillScenario.makerStateScenario,
+                    traderAssetAllowance: AllowanceAmountScenario.Unlimited,
+                },
+            };
+            await coreCombinatorialUtils.testFillOrderScenarioAsync(provider, fillScenario);
+        });
+
+        it('should successfully fill order when makerAsset and takerAsset are ERC721 and approveAll is set for them', async () => {
+            const fillScenario = {
+                ...defaultFillScenario,
+                orderScenario: {
+                    ...defaultFillScenario.orderScenario,
+                    makerAssetDataScenario: AssetDataScenario.ERC721,
+                    takerAssetDataScenario: AssetDataScenario.ERC721,
+                },
+                takerAssetFillAmountScenario: TakerAssetFillAmountScenario.ExactlyRemainingFillableTakerAssetAmount,
+                makerStateScenario: {
+                    ...defaultFillScenario.makerStateScenario,
+                    traderAssetAllowance: AllowanceAmountScenario.Unlimited,
+                },
+                takerStateScenario: {
+                    ...defaultFillScenario.takerStateScenario,
+                    traderAssetAllowance: AllowanceAmountScenario.Unlimited,
+                },
+            };
+            await coreCombinatorialUtils.testFillOrderScenarioAsync(provider, fillScenario);
+        });
+    });
+});
diff --git a/packages/contracts/test/exchange/libs.ts b/packages/contracts/test/exchange/libs.ts
index c08001198..6ded6329c 100644
--- a/packages/contracts/test/exchange/libs.ts
+++ b/packages/contracts/test/exchange/libs.ts
@@ -4,13 +4,13 @@ import { SignedOrder } from '@0xproject/types';
 import { BigNumber } from '@0xproject/utils';
 import * as chai from 'chai';
 
-import { TestLibsContract } from '../../src/generated_contract_wrappers/test_libs';
-import { addressUtils } from '../../src/utils/address_utils';
-import { artifacts } from '../../src/utils/artifacts';
-import { chaiSetup } from '../../src/utils/chai_setup';
-import { constants } from '../../src/utils/constants';
-import { OrderFactory } from '../../src/utils/order_factory';
-import { provider, txDefaults, web3Wrapper } from '../../src/utils/web3_wrapper';
+import { TestLibsContract } from '../../generated_contract_wrappers/test_libs';
+import { addressUtils } from '../utils/address_utils';
+import { artifacts } from '../utils/artifacts';
+import { chaiSetup } from '../utils/chai_setup';
+import { constants } from '../utils/constants';
+import { OrderFactory } from '../utils/order_factory';
+import { provider, txDefaults, web3Wrapper } from '../utils/web3_wrapper';
 
 chaiSetup.configure();
 const expect = chai.expect;
diff --git a/packages/contracts/test/exchange/match_orders.ts b/packages/contracts/test/exchange/match_orders.ts
index b8dca04fd..0d07d156f 100644
--- a/packages/contracts/test/exchange/match_orders.ts
+++ b/packages/contracts/test/exchange/match_orders.ts
@@ -1,27 +1,27 @@
 import { BlockchainLifecycle } from '@0xproject/dev-utils';
 import { assetProxyUtils } from '@0xproject/order-utils';
-import { AssetProxyId } from '@0xproject/types';
+import { RevertReason } from '@0xproject/types';
 import { BigNumber } from '@0xproject/utils';
 import { Web3Wrapper } from '@0xproject/web3-wrapper';
 import * as chai from 'chai';
 import * as _ from 'lodash';
 
-import { DummyERC20TokenContract } from '../../src/generated_contract_wrappers/dummy_e_r_c20_token';
-import { DummyERC721TokenContract } from '../../src/generated_contract_wrappers/dummy_e_r_c721_token';
-import { ERC20ProxyContract } from '../../src/generated_contract_wrappers/e_r_c20_proxy';
-import { ERC721ProxyContract } from '../../src/generated_contract_wrappers/e_r_c721_proxy';
-import { ExchangeContract } from '../../src/generated_contract_wrappers/exchange';
-import { artifacts } from '../../src/utils/artifacts';
-import { expectRevertOrAlwaysFailingTransactionAsync } from '../../src/utils/assertions';
-import { chaiSetup } from '../../src/utils/chai_setup';
-import { constants } from '../../src/utils/constants';
-import { ERC20Wrapper } from '../../src/utils/erc20_wrapper';
-import { ERC721Wrapper } from '../../src/utils/erc721_wrapper';
-import { ExchangeWrapper } from '../../src/utils/exchange_wrapper';
-import { MatchOrderTester } from '../../src/utils/match_order_tester';
-import { OrderFactory } from '../../src/utils/order_factory';
-import { ERC20BalancesByOwner, ERC721TokenIdsByOwner, OrderInfo, OrderStatus } from '../../src/utils/types';
-import { provider, txDefaults, web3Wrapper } from '../../src/utils/web3_wrapper';
+import { DummyERC20TokenContract } from '../../generated_contract_wrappers/dummy_e_r_c20_token';
+import { DummyERC721TokenContract } from '../../generated_contract_wrappers/dummy_e_r_c721_token';
+import { ERC20ProxyContract } from '../../generated_contract_wrappers/e_r_c20_proxy';
+import { ERC721ProxyContract } from '../../generated_contract_wrappers/e_r_c721_proxy';
+import { ExchangeContract } from '../../generated_contract_wrappers/exchange';
+import { artifacts } from '../utils/artifacts';
+import { expectRevertReasonOrAlwaysFailingTransactionAsync } from '../utils/assertions';
+import { chaiSetup } from '../utils/chai_setup';
+import { constants } from '../utils/constants';
+import { ERC20Wrapper } from '../utils/erc20_wrapper';
+import { ERC721Wrapper } from '../utils/erc721_wrapper';
+import { ExchangeWrapper } from '../utils/exchange_wrapper';
+import { MatchOrderTester } from '../utils/match_order_tester';
+import { OrderFactory } from '../utils/order_factory';
+import { ERC20BalancesByOwner, ERC721TokenIdsByOwner, OrderInfo, OrderStatus } from '../utils/types';
+import { provider, txDefaults, web3Wrapper } from '../utils/web3_wrapper';
 
 chaiSetup.configure();
 const expect = chai.expect;
@@ -76,12 +76,16 @@ describe('matchOrders', () => {
             takerAddress,
             feeRecipientAddressLeft,
             feeRecipientAddressRight,
-        ] = accounts);
+        ] = _.slice(accounts, 0, 6));
         // Create wrappers
         erc20Wrapper = new ERC20Wrapper(provider, usedAddresses, owner);
         erc721Wrapper = new ERC721Wrapper(provider, usedAddresses, owner);
         // Deploy ERC20 token & ERC20 proxy
-        [erc20TokenA, erc20TokenB, zrxToken] = await erc20Wrapper.deployDummyTokensAsync();
+        const numDummyErc20ToDeploy = 3;
+        [erc20TokenA, erc20TokenB, zrxToken] = await erc20Wrapper.deployDummyTokensAsync(
+            numDummyErc20ToDeploy,
+            constants.DUMMY_TOKEN_DECIMALS,
+        );
         erc20Proxy = await erc20Wrapper.deployProxyAsync();
         await erc20Wrapper.setBalancesAndAllowancesAsync();
         // Deploy ERC721 token and proxy
@@ -96,11 +100,11 @@ describe('matchOrders', () => {
             artifacts.Exchange,
             provider,
             txDefaults,
-            zrxToken.address,
+            assetProxyUtils.encodeERC20AssetData(zrxToken.address),
         );
         exchangeWrapper = new ExchangeWrapper(exchange, provider);
-        await exchangeWrapper.registerAssetProxyAsync(AssetProxyId.ERC20, erc20Proxy.address, owner);
-        await exchangeWrapper.registerAssetProxyAsync(AssetProxyId.ERC721, erc721Proxy.address, owner);
+        await exchangeWrapper.registerAssetProxyAsync(erc20Proxy.address, owner);
+        await exchangeWrapper.registerAssetProxyAsync(erc721Proxy.address, owner);
         // Authorize ERC20 and ERC721 trades by exchange
         await web3Wrapper.awaitTransactionSuccessAsync(
             await erc20Proxy.addAuthorizedAddress.sendTransactionAsync(exchange.address, {
@@ -598,8 +602,9 @@ describe('matchOrders', () => {
             // Cancel left order
             await exchangeWrapper.cancelOrderAsync(signedOrderLeft, signedOrderLeft.makerAddress);
             // Match orders
-            return expectRevertOrAlwaysFailingTransactionAsync(
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
                 exchangeWrapper.matchOrdersAsync(signedOrderLeft, signedOrderRight, takerAddress),
+                RevertReason.OrderUnfillable,
             );
         });
 
@@ -622,8 +627,9 @@ describe('matchOrders', () => {
             // Cancel right order
             await exchangeWrapper.cancelOrderAsync(signedOrderRight, signedOrderRight.makerAddress);
             // Match orders
-            return expectRevertOrAlwaysFailingTransactionAsync(
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
                 exchangeWrapper.matchOrdersAsync(signedOrderLeft, signedOrderRight, takerAddress),
+                RevertReason.OrderUnfillable,
             );
         });
 
@@ -644,14 +650,9 @@ describe('matchOrders', () => {
                 feeRecipientAddress: feeRecipientAddressRight,
             });
             // Match orders
-            return expectRevertOrAlwaysFailingTransactionAsync(
-                matchOrderTester.matchOrdersAndVerifyBalancesAsync(
-                    signedOrderLeft,
-                    signedOrderRight,
-                    takerAddress,
-                    erc20BalancesByOwner,
-                    erc721TokenIdsByOwner,
-                ),
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
+                exchangeWrapper.matchOrdersAsync(signedOrderLeft, signedOrderRight, takerAddress),
+                RevertReason.NegativeSpreadRequired,
             );
         });
 
@@ -672,14 +673,13 @@ describe('matchOrders', () => {
                 feeRecipientAddress: feeRecipientAddressRight,
             });
             // Match orders
-            return expectRevertOrAlwaysFailingTransactionAsync(
-                matchOrderTester.matchOrdersAndVerifyBalancesAsync(
-                    signedOrderLeft,
-                    signedOrderRight,
-                    takerAddress,
-                    erc20BalancesByOwner,
-                    erc721TokenIdsByOwner,
-                ),
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
+                exchangeWrapper.matchOrdersAsync(signedOrderLeft, signedOrderRight, takerAddress),
+                // We are assuming assetData fields of the right order are the
+                // reverse of the left order, rather than checking equality. This
+                // saves a bunch of gas, but as a result if the assetData fields are
+                // off then the failure ends up happening at signature validation
+                RevertReason.InvalidOrderSignature,
             );
         });
 
@@ -702,14 +702,9 @@ describe('matchOrders', () => {
                 feeRecipientAddress: feeRecipientAddressRight,
             });
             // Match orders
-            return expectRevertOrAlwaysFailingTransactionAsync(
-                matchOrderTester.matchOrdersAndVerifyBalancesAsync(
-                    signedOrderLeft,
-                    signedOrderRight,
-                    takerAddress,
-                    erc20BalancesByOwner,
-                    erc721TokenIdsByOwner,
-                ),
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
+                exchangeWrapper.matchOrdersAsync(signedOrderLeft, signedOrderRight, takerAddress),
+                RevertReason.InvalidOrderSignature,
             );
         });
 
diff --git a/packages/contracts/test/exchange/signature_validator.ts b/packages/contracts/test/exchange/signature_validator.ts
index 8e221e3f1..1db7dfc6d 100644
--- a/packages/contracts/test/exchange/signature_validator.ts
+++ b/packages/contracts/test/exchange/signature_validator.ts
@@ -1,6 +1,6 @@
 import { BlockchainLifecycle } from '@0xproject/dev-utils';
 import { addSignedMessagePrefix, assetProxyUtils, MessagePrefixType, orderHashUtils } from '@0xproject/order-utils';
-import { SignatureType, SignedOrder } from '@0xproject/types';
+import { RevertReason, SignatureType, SignedOrder } from '@0xproject/types';
 import * as chai from 'chai';
 import { LogWithDecodedArgs } from 'ethereum-types';
 import ethUtil = require('ethereumjs-util');
@@ -8,17 +8,17 @@ import ethUtil = require('ethereumjs-util');
 import {
     SignatureValidatorApprovalContractEventArgs,
     TestSignatureValidatorContract,
-} from '../../src/generated_contract_wrappers/test_signature_validator';
-import { TestValidatorContract } from '../../src/generated_contract_wrappers/test_validator';
-import { TestWalletContract } from '../../src/generated_contract_wrappers/test_wallet';
-import { addressUtils } from '../../src/utils/address_utils';
-import { artifacts } from '../../src/utils/artifacts';
-import { expectRevertOrOtherErrorAsync } from '../../src/utils/assertions';
-import { chaiSetup } from '../../src/utils/chai_setup';
-import { constants } from '../../src/utils/constants';
-import { LogDecoder } from '../../src/utils/log_decoder';
-import { OrderFactory } from '../../src/utils/order_factory';
-import { provider, txDefaults, web3Wrapper } from '../../src/utils/web3_wrapper';
+} from '../../generated_contract_wrappers/test_signature_validator';
+import { TestValidatorContract } from '../../generated_contract_wrappers/test_validator';
+import { TestWalletContract } from '../../generated_contract_wrappers/test_wallet';
+import { addressUtils } from '../utils/address_utils';
+import { artifacts } from '../utils/artifacts';
+import { expectRevertOrOtherErrorAsync } from '../utils/assertions';
+import { chaiSetup } from '../utils/chai_setup';
+import { constants } from '../utils/constants';
+import { LogDecoder } from '../utils/log_decoder';
+import { OrderFactory } from '../utils/order_factory';
+import { provider, txDefaults, web3Wrapper } from '../utils/web3_wrapper';
 
 chaiSetup.configure();
 const expect = chai.expect;
@@ -107,7 +107,7 @@ describe('MixinSignatureValidator', () => {
                     signedOrder.makerAddress,
                     emptySignature,
                 ),
-                constants.EXCHANGE_LENGTH_GREATER_THAN_0_REQUIRED,
+                RevertReason.LengthGreaterThan0Required,
             );
         });
 
@@ -121,7 +121,7 @@ describe('MixinSignatureValidator', () => {
                     signedOrder.makerAddress,
                     unsupportedSignatureHex,
                 ),
-                constants.EXCHANGE_SIGNATURE_UNSUPPORTED,
+                RevertReason.SignatureUnsupported,
             );
         });
 
@@ -134,7 +134,7 @@ describe('MixinSignatureValidator', () => {
                     signedOrder.makerAddress,
                     unsupportedSignatureHex,
                 ),
-                constants.EXCHANGE_SIGNATURE_ILLEGAL,
+                RevertReason.SignatureIllegal,
             );
         });
 
@@ -161,7 +161,7 @@ describe('MixinSignatureValidator', () => {
                     signedOrder.makerAddress,
                     signatureHex,
                 ),
-                constants.EXCHANGE_LENGTH_0_REQUIRED,
+                RevertReason.Length0Required,
             );
         });
 
diff --git a/packages/contracts/test/exchange/transactions.ts b/packages/contracts/test/exchange/transactions.ts
index 9a625880c..4f8b49e0e 100644
--- a/packages/contracts/test/exchange/transactions.ts
+++ b/packages/contracts/test/exchange/transactions.ts
@@ -1,25 +1,26 @@
 import { BlockchainLifecycle } from '@0xproject/dev-utils';
 import { assetProxyUtils, generatePseudoRandomSalt } from '@0xproject/order-utils';
-import { AssetProxyId, OrderWithoutExchangeAddress, SignedOrder } from '@0xproject/types';
+import { OrderWithoutExchangeAddress, RevertReason, SignedOrder } from '@0xproject/types';
 import { BigNumber } from '@0xproject/utils';
 import * as chai from 'chai';
-
-import { DummyERC20TokenContract } from '../../src/generated_contract_wrappers/dummy_e_r_c20_token';
-import { ERC20ProxyContract } from '../../src/generated_contract_wrappers/e_r_c20_proxy';
-import { ExchangeContract } from '../../src/generated_contract_wrappers/exchange';
-import { ExchangeWrapperContract } from '../../src/generated_contract_wrappers/exchange_wrapper';
-import { WhitelistContract } from '../../src/generated_contract_wrappers/whitelist';
-import { artifacts } from '../../src/utils/artifacts';
-import { expectRevertOrAlwaysFailingTransactionAsync } from '../../src/utils/assertions';
-import { chaiSetup } from '../../src/utils/chai_setup';
-import { constants } from '../../src/utils/constants';
-import { ERC20Wrapper } from '../../src/utils/erc20_wrapper';
-import { ExchangeWrapper } from '../../src/utils/exchange_wrapper';
-import { OrderFactory } from '../../src/utils/order_factory';
-import { orderUtils } from '../../src/utils/order_utils';
-import { TransactionFactory } from '../../src/utils/transaction_factory';
-import { ERC20BalancesByOwner, SignedTransaction } from '../../src/utils/types';
-import { provider, txDefaults, web3Wrapper } from '../../src/utils/web3_wrapper';
+import * as _ from 'lodash';
+
+import { DummyERC20TokenContract } from '../../generated_contract_wrappers/dummy_e_r_c20_token';
+import { ERC20ProxyContract } from '../../generated_contract_wrappers/e_r_c20_proxy';
+import { ExchangeContract } from '../../generated_contract_wrappers/exchange';
+import { ExchangeWrapperContract } from '../../generated_contract_wrappers/exchange_wrapper';
+import { WhitelistContract } from '../../generated_contract_wrappers/whitelist';
+import { artifacts } from '../utils/artifacts';
+import { expectRevertReasonOrAlwaysFailingTransactionAsync } from '../utils/assertions';
+import { chaiSetup } from '../utils/chai_setup';
+import { constants } from '../utils/constants';
+import { ERC20Wrapper } from '../utils/erc20_wrapper';
+import { ExchangeWrapper } from '../utils/exchange_wrapper';
+import { OrderFactory } from '../utils/order_factory';
+import { orderUtils } from '../utils/order_utils';
+import { TransactionFactory } from '../utils/transaction_factory';
+import { ERC20BalancesByOwner, SignedTransaction } from '../utils/types';
+import { provider, txDefaults, web3Wrapper } from '../utils/web3_wrapper';
 
 chaiSetup.configure();
 const expect = chai.expect;
@@ -59,13 +60,27 @@ describe('Exchange transactions', () => {
     after(async () => {
         await blockchainLifecycle.revertAsync();
     });
+    beforeEach(async () => {
+        await blockchainLifecycle.startAsync();
+    });
+    afterEach(async () => {
+        await blockchainLifecycle.revertAsync();
+    });
     before(async () => {
         const accounts = await web3Wrapper.getAvailableAddressesAsync();
-        const usedAddresses = ([owner, senderAddress, makerAddress, takerAddress, feeRecipientAddress] = accounts);
+        const usedAddresses = ([owner, senderAddress, makerAddress, takerAddress, feeRecipientAddress] = _.slice(
+            accounts,
+            0,
+            5,
+        ));
 
         erc20Wrapper = new ERC20Wrapper(provider, usedAddresses, owner);
 
-        [erc20TokenA, erc20TokenB, zrxToken] = await erc20Wrapper.deployDummyTokensAsync();
+        const numDummyErc20ToDeploy = 3;
+        [erc20TokenA, erc20TokenB, zrxToken] = await erc20Wrapper.deployDummyTokensAsync(
+            numDummyErc20ToDeploy,
+            constants.DUMMY_TOKEN_DECIMALS,
+        );
         erc20Proxy = await erc20Wrapper.deployProxyAsync();
         await erc20Wrapper.setBalancesAndAllowancesAsync();
 
@@ -73,10 +88,10 @@ describe('Exchange transactions', () => {
             artifacts.Exchange,
             provider,
             txDefaults,
-            zrxToken.address,
+            assetProxyUtils.encodeERC20AssetData(zrxToken.address),
         );
         exchangeWrapper = new ExchangeWrapper(exchange, provider);
-        await exchangeWrapper.registerAssetProxyAsync(AssetProxyId.ERC20, erc20Proxy.address, owner);
+        await exchangeWrapper.registerAssetProxyAsync(erc20Proxy.address, owner);
 
         await web3Wrapper.awaitTransactionSuccessAsync(
             await erc20Proxy.addAuthorizedAddress.sendTransactionAsync(exchange.address, { from: owner }),
@@ -101,13 +116,6 @@ describe('Exchange transactions', () => {
         makerTransactionFactory = new TransactionFactory(makerPrivateKey, exchange.address);
         takerTransactionFactory = new TransactionFactory(takerPrivateKey, exchange.address);
     });
-    beforeEach(async () => {
-        await blockchainLifecycle.startAsync();
-    });
-    afterEach(async () => {
-        await blockchainLifecycle.revertAsync();
-    });
-
     describe('executeTransaction', () => {
         describe('fillOrder', () => {
             let takerAssetFillAmount: BigNumber;
@@ -126,8 +134,9 @@ describe('Exchange transactions', () => {
             });
 
             it('should throw if not called by specified sender', async () => {
-                return expectRevertOrAlwaysFailingTransactionAsync(
+                return expectRevertReasonOrAlwaysFailingTransactionAsync(
                     exchangeWrapper.executeTransactionAsync(signedTx, takerAddress),
+                    RevertReason.FailedExecution,
                 );
             });
 
@@ -168,8 +177,9 @@ describe('Exchange transactions', () => {
 
             it('should throw if the a 0x transaction with the same transactionHash has already been executed', async () => {
                 await exchangeWrapper.executeTransactionAsync(signedTx, senderAddress);
-                return expectRevertOrAlwaysFailingTransactionAsync(
+                return expectRevertReasonOrAlwaysFailingTransactionAsync(
                     exchangeWrapper.executeTransactionAsync(signedTx, senderAddress),
+                    RevertReason.InvalidTxHash,
                 );
             });
 
@@ -187,15 +197,17 @@ describe('Exchange transactions', () => {
             });
 
             it('should throw if not called by specified sender', async () => {
-                return expectRevertOrAlwaysFailingTransactionAsync(
+                return expectRevertReasonOrAlwaysFailingTransactionAsync(
                     exchangeWrapper.executeTransactionAsync(signedTx, makerAddress),
+                    RevertReason.FailedExecution,
                 );
             });
 
             it('should cancel the order when signed by maker and called by sender', async () => {
                 await exchangeWrapper.executeTransactionAsync(signedTx, senderAddress);
-                return expectRevertOrAlwaysFailingTransactionAsync(
+                return expectRevertReasonOrAlwaysFailingTransactionAsync(
                     exchangeWrapper.fillOrderAsync(signedOrder, senderAddress),
+                    RevertReason.OrderUnfillable,
                 );
             });
         });
@@ -238,7 +250,7 @@ describe('Exchange transactions', () => {
                     signedOrder.signature,
                 );
                 const signedFillTx = takerTransactionFactory.newSignedTransaction(fillData);
-                return expectRevertOrAlwaysFailingTransactionAsync(
+                return expectRevertReasonOrAlwaysFailingTransactionAsync(
                     exchangeWrapperContract.fillOrder.sendTransactionAsync(
                         orderWithoutExchangeAddress,
                         takerAssetFillAmount,
@@ -247,6 +259,7 @@ describe('Exchange transactions', () => {
                         signedFillTx.signature,
                         { from: takerAddress },
                     ),
+                    RevertReason.FailedExecution,
                 );
             });
 
@@ -357,7 +370,7 @@ describe('Exchange transactions', () => {
             orderWithoutExchangeAddress = orderUtils.getOrderWithoutExchangeAddress(signedOrder);
             const takerAssetFillAmount = signedOrder.takerAssetAmount;
             const salt = generatePseudoRandomSalt();
-            return expectRevertOrAlwaysFailingTransactionAsync(
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
                 whitelist.fillOrderIfWhitelisted.sendTransactionAsync(
                     orderWithoutExchangeAddress,
                     takerAssetFillAmount,
@@ -365,6 +378,7 @@ describe('Exchange transactions', () => {
                     signedOrder.signature,
                     { from: takerAddress },
                 ),
+                RevertReason.MakerNotWhitelisted,
             );
         });
 
@@ -378,7 +392,7 @@ describe('Exchange transactions', () => {
             orderWithoutExchangeAddress = orderUtils.getOrderWithoutExchangeAddress(signedOrder);
             const takerAssetFillAmount = signedOrder.takerAssetAmount;
             const salt = generatePseudoRandomSalt();
-            return expectRevertOrAlwaysFailingTransactionAsync(
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
                 whitelist.fillOrderIfWhitelisted.sendTransactionAsync(
                     orderWithoutExchangeAddress,
                     takerAssetFillAmount,
@@ -386,6 +400,7 @@ describe('Exchange transactions', () => {
                     signedOrder.signature,
                     { from: takerAddress },
                 ),
+                RevertReason.TakerNotWhitelisted,
             );
         });
 
diff --git a/packages/contracts/test/exchange/wrapper.ts b/packages/contracts/test/exchange/wrapper.ts
index 703f644b8..7942f7695 100644
--- a/packages/contracts/test/exchange/wrapper.ts
+++ b/packages/contracts/test/exchange/wrapper.ts
@@ -1,26 +1,26 @@
 import { BlockchainLifecycle } from '@0xproject/dev-utils';
 import { assetProxyUtils } from '@0xproject/order-utils';
-import { AssetProxyId, SignedOrder } from '@0xproject/types';
+import { RevertReason, SignedOrder } from '@0xproject/types';
 import { BigNumber } from '@0xproject/utils';
 import { Web3Wrapper } from '@0xproject/web3-wrapper';
 import * as chai from 'chai';
 import * as _ from 'lodash';
 
-import { DummyERC20TokenContract } from '../../src/generated_contract_wrappers/dummy_e_r_c20_token';
-import { DummyERC721TokenContract } from '../../src/generated_contract_wrappers/dummy_e_r_c721_token';
-import { ERC20ProxyContract } from '../../src/generated_contract_wrappers/e_r_c20_proxy';
-import { ERC721ProxyContract } from '../../src/generated_contract_wrappers/e_r_c721_proxy';
-import { ExchangeContract } from '../../src/generated_contract_wrappers/exchange';
-import { artifacts } from '../../src/utils/artifacts';
-import { expectRevertOrAlwaysFailingTransactionAsync } from '../../src/utils/assertions';
-import { chaiSetup } from '../../src/utils/chai_setup';
-import { constants } from '../../src/utils/constants';
-import { ERC20Wrapper } from '../../src/utils/erc20_wrapper';
-import { ERC721Wrapper } from '../../src/utils/erc721_wrapper';
-import { ExchangeWrapper } from '../../src/utils/exchange_wrapper';
-import { OrderFactory } from '../../src/utils/order_factory';
-import { ERC20BalancesByOwner } from '../../src/utils/types';
-import { provider, txDefaults, web3Wrapper } from '../../src/utils/web3_wrapper';
+import { DummyERC20TokenContract } from '../../generated_contract_wrappers/dummy_e_r_c20_token';
+import { DummyERC721TokenContract } from '../../generated_contract_wrappers/dummy_e_r_c721_token';
+import { ERC20ProxyContract } from '../../generated_contract_wrappers/e_r_c20_proxy';
+import { ERC721ProxyContract } from '../../generated_contract_wrappers/e_r_c721_proxy';
+import { ExchangeContract } from '../../generated_contract_wrappers/exchange';
+import { artifacts } from '../utils/artifacts';
+import { expectRevertReasonOrAlwaysFailingTransactionAsync } from '../utils/assertions';
+import { chaiSetup } from '../utils/chai_setup';
+import { constants } from '../utils/constants';
+import { ERC20Wrapper } from '../utils/erc20_wrapper';
+import { ERC721Wrapper } from '../utils/erc721_wrapper';
+import { ExchangeWrapper } from '../utils/exchange_wrapper';
+import { OrderFactory } from '../utils/order_factory';
+import { ERC20BalancesByOwner } from '../utils/types';
+import { provider, txDefaults, web3Wrapper } from '../utils/web3_wrapper';
 
 chaiSetup.configure();
 const expect = chai.expect;
@@ -60,12 +60,16 @@ describe('Exchange wrappers', () => {
     });
     before(async () => {
         const accounts = await web3Wrapper.getAvailableAddressesAsync();
-        const usedAddresses = ([owner, makerAddress, takerAddress, feeRecipientAddress] = accounts);
+        const usedAddresses = ([owner, makerAddress, takerAddress, feeRecipientAddress] = _.slice(accounts, 0, 4));
 
         erc20Wrapper = new ERC20Wrapper(provider, usedAddresses, owner);
         erc721Wrapper = new ERC721Wrapper(provider, usedAddresses, owner);
 
-        [erc20TokenA, erc20TokenB, zrxToken] = await erc20Wrapper.deployDummyTokensAsync();
+        const numDummyErc20ToDeploy = 3;
+        [erc20TokenA, erc20TokenB, zrxToken] = await erc20Wrapper.deployDummyTokensAsync(
+            numDummyErc20ToDeploy,
+            constants.DUMMY_TOKEN_DECIMALS,
+        );
         erc20Proxy = await erc20Wrapper.deployProxyAsync();
         await erc20Wrapper.setBalancesAndAllowancesAsync();
 
@@ -80,11 +84,11 @@ describe('Exchange wrappers', () => {
             artifacts.Exchange,
             provider,
             txDefaults,
-            zrxToken.address,
+            assetProxyUtils.encodeERC20AssetData(zrxToken.address),
         );
         exchangeWrapper = new ExchangeWrapper(exchange, provider);
-        await exchangeWrapper.registerAssetProxyAsync(AssetProxyId.ERC20, erc20Proxy.address, owner);
-        await exchangeWrapper.registerAssetProxyAsync(AssetProxyId.ERC721, erc721Proxy.address, owner);
+        await exchangeWrapper.registerAssetProxyAsync(erc20Proxy.address, owner);
+        await exchangeWrapper.registerAssetProxyAsync(erc721Proxy.address, owner);
 
         await web3Wrapper.awaitTransactionSuccessAsync(
             await erc20Proxy.addAuthorizedAddress.sendTransactionAsync(exchange.address, {
@@ -165,13 +169,14 @@ describe('Exchange wrappers', () => {
             );
         });
 
-        it('should throw if an signedOrder is expired', async () => {
+        it('should throw if a signedOrder is expired', async () => {
             const signedOrder = orderFactory.newSignedOrder({
                 expirationTimeSeconds: new BigNumber(Math.floor((Date.now() - 10000) / 1000)),
             });
 
-            return expectRevertOrAlwaysFailingTransactionAsync(
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
                 exchangeWrapper.fillOrKillOrderAsync(signedOrder, takerAddress),
+                RevertReason.OrderUnfillable,
             );
         });
 
@@ -182,8 +187,9 @@ describe('Exchange wrappers', () => {
                 takerAssetFillAmount: signedOrder.takerAssetAmount.div(2),
             });
 
-            return expectRevertOrAlwaysFailingTransactionAsync(
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
                 exchangeWrapper.fillOrKillOrderAsync(signedOrder, takerAddress),
+                RevertReason.CompleteFillFailed,
             );
         });
     });
@@ -368,7 +374,7 @@ describe('Exchange wrappers', () => {
                 // HACK(albrow): We need to hardcode the gas estimate here because
                 // the Geth gas estimator doesn't work with the way we use
                 // delegatecall and swallow errors.
-                gas: 270000,
+                gas: 280000,
             });
             // Verify post-conditions
             const newOwnerMakerAsset = await erc721Token.ownerOf.callAsync(makerAssetId);
@@ -494,10 +500,11 @@ describe('Exchange wrappers', () => {
 
                 await exchangeWrapper.fillOrKillOrderAsync(signedOrders[0], takerAddress);
 
-                return expectRevertOrAlwaysFailingTransactionAsync(
+                return expectRevertReasonOrAlwaysFailingTransactionAsync(
                     exchangeWrapper.batchFillOrKillOrdersAsync(signedOrders, takerAddress, {
                         takerAssetFillAmounts,
                     }),
+                    RevertReason.OrderUnfillable,
                 );
             });
         });
@@ -687,7 +694,7 @@ describe('Exchange wrappers', () => {
                 expect(newBalances).to.be.deep.equal(erc20Balances);
             });
 
-            it('should throw when an signedOrder does not use the same takerAssetAddress', async () => {
+            it('should throw when a signedOrder does not use the same takerAssetAddress', async () => {
                 signedOrders = [
                     orderFactory.newSignedOrder(),
                     orderFactory.newSignedOrder({
@@ -696,10 +703,13 @@ describe('Exchange wrappers', () => {
                     orderFactory.newSignedOrder(),
                 ];
 
-                return expectRevertOrAlwaysFailingTransactionAsync(
+                return expectRevertReasonOrAlwaysFailingTransactionAsync(
                     exchangeWrapper.marketSellOrdersAsync(signedOrders, takerAddress, {
                         takerAssetFillAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(1000), 18),
                     }),
+                    // We simply use the takerAssetData from the first order for all orders.
+                    // If they are not the same, the contract throws when validating the order signature
+                    RevertReason.InvalidOrderSignature,
                 );
             });
         });
@@ -902,7 +912,7 @@ describe('Exchange wrappers', () => {
                 expect(newBalances).to.be.deep.equal(erc20Balances);
             });
 
-            it('should throw when an signedOrder does not use the same makerAssetAddress', async () => {
+            it('should throw when a signedOrder does not use the same makerAssetAddress', async () => {
                 signedOrders = [
                     orderFactory.newSignedOrder(),
                     orderFactory.newSignedOrder({
@@ -911,10 +921,11 @@ describe('Exchange wrappers', () => {
                     orderFactory.newSignedOrder(),
                 ];
 
-                return expectRevertOrAlwaysFailingTransactionAsync(
+                return expectRevertReasonOrAlwaysFailingTransactionAsync(
                     exchangeWrapper.marketBuyOrdersAsync(signedOrders, takerAddress, {
                         makerAssetFillAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(1000), 18),
                     }),
+                    RevertReason.InvalidOrderSignature,
                 );
             });
         });
diff --git a/packages/contracts/test/global_hooks.ts b/packages/contracts/test/global_hooks.ts
index 83263c5b3..cf7c52efd 100644
--- a/packages/contracts/test/global_hooks.ts
+++ b/packages/contracts/test/global_hooks.ts
@@ -1,7 +1,7 @@
 import { env, EnvVars } from '@0xproject/dev-utils';
 
-import { coverage } from '../src/utils/coverage';
-import { profiler } from '../src/utils/profiler';
+import { coverage } from './utils/coverage';
+import { profiler } from './utils/profiler';
 
 after('generate coverage report', async () => {
     if (env.parseBoolean(EnvVars.SolidityCoverage)) {
diff --git a/packages/contracts/test/libraries/lib_bytes.ts b/packages/contracts/test/libraries/lib_bytes.ts
index 56f1dc2bc..963b51b8f 100644
--- a/packages/contracts/test/libraries/lib_bytes.ts
+++ b/packages/contracts/test/libraries/lib_bytes.ts
@@ -1,17 +1,18 @@
 import { BlockchainLifecycle } from '@0xproject/dev-utils';
 import { assetProxyUtils, generatePseudoRandomSalt } from '@0xproject/order-utils';
+import { RevertReason } from '@0xproject/types';
 import { BigNumber } from '@0xproject/utils';
 import BN = require('bn.js');
 import * as chai from 'chai';
 import ethUtil = require('ethereumjs-util');
 import * as _ from 'lodash';
 
-import { TestLibBytesContract } from '../../src/generated_contract_wrappers/test_lib_bytes';
-import { artifacts } from '../../src/utils/artifacts';
-import { expectRevertOrOtherErrorAsync } from '../../src/utils/assertions';
-import { chaiSetup } from '../../src/utils/chai_setup';
-import { constants } from '../../src/utils/constants';
-import { provider, txDefaults, web3Wrapper } from '../../src/utils/web3_wrapper';
+import { TestLibBytesContract } from '../../generated_contract_wrappers/test_lib_bytes';
+import { artifacts } from '../utils/artifacts';
+import { expectRevertOrOtherErrorAsync } from '../utils/assertions';
+import { chaiSetup } from '../utils/chai_setup';
+import { constants } from '../utils/constants';
+import { provider, txDefaults, web3Wrapper } from '../utils/web3_wrapper';
 
 chaiSetup.configure();
 const expect = chai.expect;
@@ -101,7 +102,7 @@ describe('LibBytes', () => {
         it('should revert if length is 0', async () => {
             return expectRevertOrOtherErrorAsync(
                 libBytes.publicPopLastByte.callAsync(constants.NULL_BYTES),
-                constants.LIB_BYTES_GREATER_THAN_ZERO_LENGTH_REQUIRED,
+                RevertReason.LibBytesGreaterThanZeroLengthRequired,
             );
         });
         it('should pop the last byte from the input and return it', async () => {
@@ -117,7 +118,7 @@ describe('LibBytes', () => {
         it('should revert if length is less than 20', async () => {
             return expectRevertOrOtherErrorAsync(
                 libBytes.publicPopLast20Bytes.callAsync(byteArrayShorterThan20Bytes),
-                constants.LIB_BYTES_GREATER_OR_EQUAL_TO_20_LENGTH_REQUIRED,
+                RevertReason.LibBytesGreaterOrEqualTo20LengthRequired,
             );
         });
         it('should pop the last 20 bytes from the input and return it', async () => {
@@ -185,7 +186,7 @@ describe('LibBytes', () => {
         it('should revert if dest is shorter than source', async () => {
             return expectRevertOrOtherErrorAsync(
                 libBytes.publicDeepCopyBytes.callAsync(byteArrayShorterThan32Bytes, byteArrayLongerThan32Bytes),
-                constants.LIB_BYTES_GREATER_OR_EQUAL_TO_SOURCE_BYTES_LENGTH_REQUIRED,
+                RevertReason.LibBytesGreaterOrEqualToSourceBytesLengthRequired,
             );
         });
         it('should overwrite dest with source if source and dest have equal length', async () => {
@@ -238,7 +239,7 @@ describe('LibBytes', () => {
             const offset = new BigNumber(0);
             return expectRevertOrOtherErrorAsync(
                 libBytes.publicReadAddress.callAsync(shortByteArray, offset),
-                constants.LIB_BYTES_GREATER_OR_EQUAL_TO_20_LENGTH_REQUIRED,
+                RevertReason.LibBytesGreaterOrEqualTo20LengthRequired,
             );
         });
         it('should fail if the length between the offset and end of the byte array is too short to hold an address', async () => {
@@ -246,7 +247,7 @@ describe('LibBytes', () => {
             const badOffset = new BigNumber(ethUtil.toBuffer(byteArray).byteLength);
             return expectRevertOrOtherErrorAsync(
                 libBytes.publicReadAddress.callAsync(byteArray, badOffset),
-                constants.LIB_BYTES_GREATER_OR_EQUAL_TO_20_LENGTH_REQUIRED,
+                RevertReason.LibBytesGreaterOrEqualTo20LengthRequired,
             );
         });
     });
@@ -282,7 +283,7 @@ describe('LibBytes', () => {
             const offset = new BigNumber(0);
             return expectRevertOrOtherErrorAsync(
                 libBytes.publicWriteAddress.callAsync(byteArrayShorterThan20Bytes, offset, testAddress),
-                constants.LIB_BYTES_GREATER_OR_EQUAL_TO_20_LENGTH_REQUIRED,
+                RevertReason.LibBytesGreaterOrEqualTo20LengthRequired,
             );
         });
         it('should fail if the length between the offset and end of the byte array is too short to hold an address', async () => {
@@ -290,7 +291,7 @@ describe('LibBytes', () => {
             const badOffset = new BigNumber(ethUtil.toBuffer(byteArray).byteLength);
             return expectRevertOrOtherErrorAsync(
                 libBytes.publicWriteAddress.callAsync(byteArray, badOffset, testAddress),
-                constants.LIB_BYTES_GREATER_OR_EQUAL_TO_20_LENGTH_REQUIRED,
+                RevertReason.LibBytesGreaterOrEqualTo20LengthRequired,
             );
         });
     });
@@ -314,14 +315,14 @@ describe('LibBytes', () => {
             const offset = new BigNumber(0);
             return expectRevertOrOtherErrorAsync(
                 libBytes.publicReadBytes32.callAsync(byteArrayShorterThan32Bytes, offset),
-                constants.LIB_BYTES_GREATER_OR_EQUAL_TO_32_LENGTH_REQUIRED,
+                RevertReason.LibBytesGreaterOrEqualTo32LengthRequired,
             );
         });
         it('should fail if the length between the offset and end of the byte array is too short to hold a bytes32', async () => {
             const badOffset = new BigNumber(ethUtil.toBuffer(testBytes32).byteLength);
             return expectRevertOrOtherErrorAsync(
                 libBytes.publicReadBytes32.callAsync(testBytes32, badOffset),
-                constants.LIB_BYTES_GREATER_OR_EQUAL_TO_32_LENGTH_REQUIRED,
+                RevertReason.LibBytesGreaterOrEqualTo32LengthRequired,
             );
         });
     });
@@ -357,7 +358,7 @@ describe('LibBytes', () => {
             const offset = new BigNumber(0);
             return expectRevertOrOtherErrorAsync(
                 libBytes.publicWriteBytes32.callAsync(byteArrayShorterThan32Bytes, offset, testBytes32),
-                constants.LIB_BYTES_GREATER_OR_EQUAL_TO_32_LENGTH_REQUIRED,
+                RevertReason.LibBytesGreaterOrEqualTo32LengthRequired,
             );
         });
         it('should fail if the length between the offset and end of the byte array is too short to hold a bytes32', async () => {
@@ -365,7 +366,7 @@ describe('LibBytes', () => {
             const badOffset = new BigNumber(ethUtil.toBuffer(byteArray).byteLength);
             return expectRevertOrOtherErrorAsync(
                 libBytes.publicWriteBytes32.callAsync(byteArray, badOffset, testBytes32),
-                constants.LIB_BYTES_GREATER_OR_EQUAL_TO_32_LENGTH_REQUIRED,
+                RevertReason.LibBytesGreaterOrEqualTo32LengthRequired,
             );
         });
     });
@@ -393,7 +394,7 @@ describe('LibBytes', () => {
             const offset = new BigNumber(0);
             return expectRevertOrOtherErrorAsync(
                 libBytes.publicReadUint256.callAsync(byteArrayShorterThan32Bytes, offset),
-                constants.LIB_BYTES_GREATER_OR_EQUAL_TO_32_LENGTH_REQUIRED,
+                RevertReason.LibBytesGreaterOrEqualTo32LengthRequired,
             );
         });
         it('should fail if the length between the offset and end of the byte array is too short to hold a uint256', async () => {
@@ -403,7 +404,7 @@ describe('LibBytes', () => {
             const badOffset = new BigNumber(testUint256AsBuffer.byteLength);
             return expectRevertOrOtherErrorAsync(
                 libBytes.publicReadUint256.callAsync(byteArray, badOffset),
-                constants.LIB_BYTES_GREATER_OR_EQUAL_TO_32_LENGTH_REQUIRED,
+                RevertReason.LibBytesGreaterOrEqualTo32LengthRequired,
             );
         });
     });
@@ -443,7 +444,7 @@ describe('LibBytes', () => {
             const offset = new BigNumber(0);
             return expectRevertOrOtherErrorAsync(
                 libBytes.publicWriteUint256.callAsync(byteArrayShorterThan32Bytes, offset, testUint256),
-                constants.LIB_BYTES_GREATER_OR_EQUAL_TO_32_LENGTH_REQUIRED,
+                RevertReason.LibBytesGreaterOrEqualTo32LengthRequired,
             );
         });
         it('should fail if the length between the offset and end of the byte array is too short to hold a uint256', async () => {
@@ -451,7 +452,7 @@ describe('LibBytes', () => {
             const badOffset = new BigNumber(ethUtil.toBuffer(byteArray).byteLength);
             return expectRevertOrOtherErrorAsync(
                 libBytes.publicWriteUint256.callAsync(byteArray, badOffset, testUint256),
-                constants.LIB_BYTES_GREATER_OR_EQUAL_TO_32_LENGTH_REQUIRED,
+                RevertReason.LibBytesGreaterOrEqualTo32LengthRequired,
             );
         });
     });
@@ -462,7 +463,7 @@ describe('LibBytes', () => {
             const byteArrayLessThan4Bytes = '0x010101';
             return expectRevertOrOtherErrorAsync(
                 libBytes.publicReadBytes4.callAsync(byteArrayLessThan4Bytes, new BigNumber(0)),
-                constants.LIB_BYTES_GREATER_OR_EQUAL_TO_4_LENGTH_REQUIRED,
+                RevertReason.LibBytesGreaterOrEqualTo4LengthRequired,
             );
         });
         it('should return the first 4 bytes of a byte array of arbitrary length', async () => {
@@ -517,28 +518,28 @@ describe('LibBytes', () => {
             const offset = new BigNumber(0);
             return expectRevertOrOtherErrorAsync(
                 libBytes.publicReadBytesWithLength.callAsync(byteArrayShorterThan32Bytes, offset),
-                constants.LIB_BYTES_GREATER_OR_EQUAL_TO_32_LENGTH_REQUIRED,
+                RevertReason.LibBytesGreaterOrEqualTo32LengthRequired,
             );
         });
         it('should fail if we store a nested byte array length, without a nested byte array', async () => {
             const offset = new BigNumber(0);
             return expectRevertOrOtherErrorAsync(
                 libBytes.publicReadBytesWithLength.callAsync(testBytes32, offset),
-                constants.LIB_BYTES_GREATER_OR_EQUAL_TO_NESTED_BYTES_LENGTH_REQUIRED,
+                RevertReason.LibBytesGreaterOrEqualToNestedBytesLengthRequired,
             );
         });
         it('should fail if the length between the offset and end of the byte array is too short to hold the length of a nested byte array', async () => {
             const badOffset = new BigNumber(ethUtil.toBuffer(byteArrayShorterThan32Bytes).byteLength);
             return expectRevertOrOtherErrorAsync(
                 libBytes.publicReadBytesWithLength.callAsync(byteArrayShorterThan32Bytes, badOffset),
-                constants.LIB_BYTES_GREATER_OR_EQUAL_TO_32_LENGTH_REQUIRED,
+                RevertReason.LibBytesGreaterOrEqualTo32LengthRequired,
             );
         });
         it('should fail if the length between the offset and end of the byte array is too short to hold the nested byte array', async () => {
             const badOffset = new BigNumber(ethUtil.toBuffer(testBytes32).byteLength);
             return expectRevertOrOtherErrorAsync(
                 libBytes.publicReadBytesWithLength.callAsync(testBytes32, badOffset),
-                constants.LIB_BYTES_GREATER_OR_EQUAL_TO_32_LENGTH_REQUIRED,
+                RevertReason.LibBytesGreaterOrEqualTo32LengthRequired,
             );
         });
     });
@@ -650,7 +651,7 @@ describe('LibBytes', () => {
             const emptyByteArray = ethUtil.bufferToHex(new Buffer(1));
             return expectRevertOrOtherErrorAsync(
                 libBytes.publicWriteBytesWithLength.callAsync(emptyByteArray, offset, longData),
-                constants.LIB_BYTES_GREATER_OR_EQUAL_TO_NESTED_BYTES_LENGTH_REQUIRED,
+                RevertReason.LibBytesGreaterOrEqualToNestedBytesLengthRequired,
             );
         });
         it('should fail if the length between the offset and end of the byte array is too short to hold the length of a nested byte array)', async () => {
@@ -658,7 +659,7 @@ describe('LibBytes', () => {
             const badOffset = new BigNumber(ethUtil.toBuffer(shortTestBytesAsBuffer).byteLength);
             return expectRevertOrOtherErrorAsync(
                 libBytes.publicWriteBytesWithLength.callAsync(emptyByteArray, badOffset, shortData),
-                constants.LIB_BYTES_GREATER_OR_EQUAL_TO_NESTED_BYTES_LENGTH_REQUIRED,
+                RevertReason.LibBytesGreaterOrEqualToNestedBytesLengthRequired,
             );
         });
     });
diff --git a/packages/contracts/test/asset_proxy_owner.ts b/packages/contracts/test/multisig/asset_proxy_owner.ts
index 188cba5a3..cde86dd46 100644
--- a/packages/contracts/test/asset_proxy_owner.ts
+++ b/packages/contracts/test/multisig/asset_proxy_owner.ts
@@ -9,19 +9,19 @@ import {
     ExecutionContractEventArgs,
     ExecutionFailureContractEventArgs,
     SubmissionContractEventArgs,
-} from '../src/generated_contract_wrappers/asset_proxy_owner';
-import { MixinAuthorizableContract } from '../src/generated_contract_wrappers/mixin_authorizable';
-import { TestAssetProxyOwnerContract } from '../src/generated_contract_wrappers/test_asset_proxy_owner';
-import { artifacts } from '../src/utils/artifacts';
+} from '../../generated_contract_wrappers/asset_proxy_owner';
+import { MixinAuthorizableContract } from '../../generated_contract_wrappers/mixin_authorizable';
+import { TestAssetProxyOwnerContract } from '../../generated_contract_wrappers/test_asset_proxy_owner';
+import { artifacts } from '../utils/artifacts';
 import {
     expectRevertOrAlwaysFailingTransactionAsync,
     expectRevertOrContractCallFailedAsync,
-} from '../src/utils/assertions';
-import { chaiSetup } from '../src/utils/chai_setup';
-import { constants } from '../src/utils/constants';
-import { increaseTimeAndMineBlockAsync } from '../src/utils/increase_time';
-import { MultiSigWrapper } from '../src/utils/multi_sig_wrapper';
-import { provider, txDefaults, web3Wrapper } from '../src/utils/web3_wrapper';
+} from '../utils/assertions';
+import { chaiSetup } from '../utils/chai_setup';
+import { constants } from '../utils/constants';
+import { increaseTimeAndMineBlockAsync } from '../utils/increase_time';
+import { MultiSigWrapper } from '../utils/multi_sig_wrapper';
+import { provider, txDefaults, web3Wrapper } from '../utils/web3_wrapper';
 
 chaiSetup.configure();
 const expect = chai.expect;
diff --git a/packages/contracts/test/multi_sig_with_time_lock.ts b/packages/contracts/test/multisig/multi_sig_with_time_lock.ts
index aa82b9edf..a746403d2 100644
--- a/packages/contracts/test/multi_sig_with_time_lock.ts
+++ b/packages/contracts/test/multisig/multi_sig_with_time_lock.ts
@@ -6,14 +6,14 @@ import { LogWithDecodedArgs } from 'ethereum-types';
 import {
     MultiSigWalletWithTimeLockContract,
     SubmissionContractEventArgs,
-} from '../src/generated_contract_wrappers/multi_sig_wallet_with_time_lock';
-import { artifacts } from '../src/utils/artifacts';
-import { expectRevertOrAlwaysFailingTransactionAsync } from '../src/utils/assertions';
-import { chaiSetup } from '../src/utils/chai_setup';
-import { constants } from '../src/utils/constants';
-import { increaseTimeAndMineBlockAsync } from '../src/utils/increase_time';
-import { MultiSigWrapper } from '../src/utils/multi_sig_wrapper';
-import { provider, txDefaults, web3Wrapper } from '../src/utils/web3_wrapper';
+} from '../../generated_contract_wrappers/multi_sig_wallet_with_time_lock';
+import { artifacts } from '../utils/artifacts';
+import { expectRevertOrAlwaysFailingTransactionAsync } from '../utils/assertions';
+import { chaiSetup } from '../utils/chai_setup';
+import { constants } from '../utils/constants';
+import { increaseTimeAndMineBlockAsync } from '../utils/increase_time';
+import { MultiSigWrapper } from '../utils/multi_sig_wrapper';
+import { provider, txDefaults, web3Wrapper } from '../utils/web3_wrapper';
 
 chaiSetup.configure();
 const expect = chai.expect;
diff --git a/packages/contracts/test/token_registry.ts b/packages/contracts/test/token_registry.ts
index 095cecfce..32f8cdee3 100644
--- a/packages/contracts/test/token_registry.ts
+++ b/packages/contracts/test/token_registry.ts
@@ -4,13 +4,14 @@ import * as chai from 'chai';
 import ethUtil = require('ethereumjs-util');
 import * as _ from 'lodash';
 
-import { TokenRegistryContract } from '../src/generated_contract_wrappers/token_registry';
-import { artifacts } from '../src/utils/artifacts';
-import { expectRevertOrAlwaysFailingTransactionAsync } from '../src/utils/assertions';
-import { chaiSetup } from '../src/utils/chai_setup';
-import { constants } from '../src/utils/constants';
-import { TokenRegWrapper } from '../src/utils/token_registry_wrapper';
-import { provider, txDefaults, web3Wrapper } from '../src/utils/web3_wrapper';
+import { TokenRegistryContract } from '../generated_contract_wrappers/token_registry';
+
+import { artifacts } from './utils/artifacts';
+import { expectRevertOrAlwaysFailingTransactionAsync } from './utils/assertions';
+import { chaiSetup } from './utils/chai_setup';
+import { constants } from './utils/constants';
+import { TokenRegWrapper } from './utils/token_registry_wrapper';
+import { provider, txDefaults, web3Wrapper } from './utils/web3_wrapper';
 
 chaiSetup.configure();
 const expect = chai.expect;
diff --git a/packages/contracts/test/ether_token.ts b/packages/contracts/test/tokens/ether_token.ts
index 01093d309..25ef15595 100644
--- a/packages/contracts/test/ether_token.ts
+++ b/packages/contracts/test/tokens/ether_token.ts
@@ -3,12 +3,12 @@ import { BigNumber } from '@0xproject/utils';
 import { Web3Wrapper } from '@0xproject/web3-wrapper';
 import * as chai from 'chai';
 
-import { WETH9Contract } from '../src/generated_contract_wrappers/weth9';
-import { artifacts } from '../src/utils/artifacts';
-import { expectInsufficientFundsAsync, expectRevertOrAlwaysFailingTransactionAsync } from '../src/utils/assertions';
-import { chaiSetup } from '../src/utils/chai_setup';
-import { constants } from '../src/utils/constants';
-import { provider, txDefaults, web3Wrapper } from '../src/utils/web3_wrapper';
+import { WETH9Contract } from '../../generated_contract_wrappers/weth9';
+import { artifacts } from '../utils/artifacts';
+import { expectInsufficientFundsAsync, expectRevertOrAlwaysFailingTransactionAsync } from '../utils/assertions';
+import { chaiSetup } from '../utils/chai_setup';
+import { constants } from '../utils/constants';
+import { provider, txDefaults, web3Wrapper } from '../utils/web3_wrapper';
 
 chaiSetup.configure();
 const expect = chai.expect;
diff --git a/packages/contracts/test/unlimited_allowance_token.ts b/packages/contracts/test/tokens/unlimited_allowance_token.ts
index 7132c57bf..09a24950c 100644
--- a/packages/contracts/test/unlimited_allowance_token.ts
+++ b/packages/contracts/test/tokens/unlimited_allowance_token.ts
@@ -1,13 +1,14 @@
 import { BlockchainLifecycle } from '@0xproject/dev-utils';
+import { RevertReason } from '@0xproject/types';
 import { BigNumber } from '@0xproject/utils';
 import * as chai from 'chai';
 
-import { DummyERC20TokenContract } from '../src/generated_contract_wrappers/dummy_e_r_c20_token';
-import { artifacts } from '../src/utils/artifacts';
-import { expectRevertOrOtherErrorAsync } from '../src/utils/assertions';
-import { chaiSetup } from '../src/utils/chai_setup';
-import { constants } from '../src/utils/constants';
-import { provider, txDefaults, web3Wrapper } from '../src/utils/web3_wrapper';
+import { DummyERC20TokenContract } from '../../generated_contract_wrappers/dummy_e_r_c20_token';
+import { artifacts } from '../utils/artifacts';
+import { expectRevertOrOtherErrorAsync } from '../utils/assertions';
+import { chaiSetup } from '../utils/chai_setup';
+import { constants } from '../utils/constants';
+import { provider, txDefaults, web3Wrapper } from '../utils/web3_wrapper';
 
 chaiSetup.configure();
 const expect = chai.expect;
@@ -55,7 +56,7 @@ describe('UnlimitedAllowanceToken', () => {
             const amountToTransfer = ownerBalance.plus(1);
             return expectRevertOrOtherErrorAsync(
                 token.transfer.callAsync(spender, amountToTransfer, { from: owner }),
-                constants.ERC20_INSUFFICIENT_BALANCE,
+                RevertReason.Erc20InsufficientBalance,
             );
         });
 
@@ -96,7 +97,7 @@ describe('UnlimitedAllowanceToken', () => {
                 token.transferFrom.callAsync(owner, spender, amountToTransfer, {
                     from: spender,
                 }),
-                constants.ERC20_INSUFFICIENT_BALANCE,
+                RevertReason.Erc20InsufficientBalance,
             );
         });
 
@@ -112,7 +113,7 @@ describe('UnlimitedAllowanceToken', () => {
                 token.transferFrom.callAsync(owner, spender, amountToTransfer, {
                     from: spender,
                 }),
-                constants.ERC20_INSUFFICIENT_ALLOWANCE,
+                RevertReason.Erc20InsufficientAllowance,
             );
         });
 
diff --git a/packages/contracts/test/zrx_token.ts b/packages/contracts/test/tokens/zrx_token.ts
index 01ae57d4a..a0d77c924 100644
--- a/packages/contracts/test/zrx_token.ts
+++ b/packages/contracts/test/tokens/zrx_token.ts
@@ -3,11 +3,11 @@ import { BigNumber } from '@0xproject/utils';
 import { Web3Wrapper } from '@0xproject/web3-wrapper';
 import * as chai from 'chai';
 
-import { ZRXTokenContract } from '../src/generated_contract_wrappers/zrx_token';
-import { artifacts } from '../src/utils/artifacts';
-import { chaiSetup } from '../src/utils/chai_setup';
-import { constants } from '../src/utils/constants';
-import { provider, txDefaults, web3Wrapper } from '../src/utils/web3_wrapper';
+import { ZRXTokenContract } from '../../generated_contract_wrappers/zrx_token';
+import { artifacts } from '../utils/artifacts';
+import { chaiSetup } from '../utils/chai_setup';
+import { constants } from '../utils/constants';
+import { provider, txDefaults, web3Wrapper } from '../utils/web3_wrapper';
 
 chaiSetup.configure();
 const expect = chai.expect;
diff --git a/packages/contracts/test/utils/abstract_asset_wrapper.ts b/packages/contracts/test/utils/abstract_asset_wrapper.ts
new file mode 100644
index 000000000..4b56a8502
--- /dev/null
+++ b/packages/contracts/test/utils/abstract_asset_wrapper.ts
@@ -0,0 +1,3 @@
+export abstract class AbstractAssetWrapper {
+    public abstract getProxyId(): string;
+}
diff --git a/packages/contracts/src/utils/address_utils.ts b/packages/contracts/test/utils/address_utils.ts
index a9fb6921a..a9fb6921a 100644
--- a/packages/contracts/src/utils/address_utils.ts
+++ b/packages/contracts/test/utils/address_utils.ts
diff --git a/packages/contracts/test/utils/artifacts.ts b/packages/contracts/test/utils/artifacts.ts
new file mode 100644
index 000000000..23e93c085
--- /dev/null
+++ b/packages/contracts/test/utils/artifacts.ts
@@ -0,0 +1,51 @@
+import { ContractArtifact } from '@0xproject/sol-compiler';
+
+import * as AssetProxyOwner from '../../artifacts/AssetProxyOwner.json';
+import * as DummyERC20Token from '../../artifacts/DummyERC20Token.json';
+import * as DummyERC721Receiver from '../../artifacts/DummyERC721Receiver.json';
+import * as DummyERC721Token from '../../artifacts/DummyERC721Token.json';
+import * as ERC20Proxy from '../../artifacts/ERC20Proxy.json';
+import * as ERC721Proxy from '../../artifacts/ERC721Proxy.json';
+import * as Exchange from '../../artifacts/Exchange.json';
+import * as ExchangeWrapper from '../../artifacts/ExchangeWrapper.json';
+import * as IAssetProxy from '../../artifacts/IAssetProxy.json';
+import * as MixinAuthorizable from '../../artifacts/MixinAuthorizable.json';
+import * as MultiSigWallet from '../../artifacts/MultiSigWallet.json';
+import * as MultiSigWalletWithTimeLock from '../../artifacts/MultiSigWalletWithTimeLock.json';
+import * as TestAssetProxyDispatcher from '../../artifacts/TestAssetProxyDispatcher.json';
+import * as TestAssetProxyOwner from '../../artifacts/TestAssetProxyOwner.json';
+import * as TestLibBytes from '../../artifacts/TestLibBytes.json';
+import * as TestLibs from '../../artifacts/TestLibs.json';
+import * as TestSignatureValidator from '../../artifacts/TestSignatureValidator.json';
+import * as TestValidator from '../../artifacts/TestValidator.json';
+import * as TestWallet from '../../artifacts/TestWallet.json';
+import * as TokenRegistry from '../../artifacts/TokenRegistry.json';
+import * as EtherToken from '../../artifacts/WETH9.json';
+import * as Whitelist from '../../artifacts/Whitelist.json';
+import * as ZRX from '../../artifacts/ZRXToken.json';
+
+export const artifacts = {
+    AssetProxyOwner: (AssetProxyOwner as any) as ContractArtifact,
+    DummyERC20Token: (DummyERC20Token as any) as ContractArtifact,
+    DummyERC721Receiver: (DummyERC721Receiver as any) as ContractArtifact,
+    DummyERC721Token: (DummyERC721Token as any) as ContractArtifact,
+    ERC20Proxy: (ERC20Proxy as any) as ContractArtifact,
+    ERC721Proxy: (ERC721Proxy as any) as ContractArtifact,
+    Exchange: (Exchange as any) as ContractArtifact,
+    ExchangeWrapper: (ExchangeWrapper as any) as ContractArtifact,
+    EtherToken: (EtherToken as any) as ContractArtifact,
+    IAssetProxy: (IAssetProxy as any) as ContractArtifact,
+    MixinAuthorizable: (MixinAuthorizable as any) as ContractArtifact,
+    MultiSigWallet: (MultiSigWallet as any) as ContractArtifact,
+    MultiSigWalletWithTimeLock: (MultiSigWalletWithTimeLock as any) as ContractArtifact,
+    TestAssetProxyOwner: (TestAssetProxyOwner as any) as ContractArtifact,
+    TestAssetProxyDispatcher: (TestAssetProxyDispatcher as any) as ContractArtifact,
+    TestLibBytes: (TestLibBytes as any) as ContractArtifact,
+    TestLibs: (TestLibs as any) as ContractArtifact,
+    TestSignatureValidator: (TestSignatureValidator as any) as ContractArtifact,
+    TestValidator: (TestValidator as any) as ContractArtifact,
+    TestWallet: (TestWallet as any) as ContractArtifact,
+    TokenRegistry: (TokenRegistry as any) as ContractArtifact,
+    Whitelist: (Whitelist as any) as ContractArtifact,
+    ZRX: (ZRX as any) as ContractArtifact,
+};
diff --git a/packages/contracts/src/utils/assertions.ts b/packages/contracts/test/utils/assertions.ts
index 615e648f3..baba892d3 100644
--- a/packages/contracts/src/utils/assertions.ts
+++ b/packages/contracts/test/utils/assertions.ts
@@ -1,7 +1,10 @@
+import { RevertReason } from '@0xproject/types';
 import * as chai from 'chai';
+import { TransactionReceipt, TransactionReceiptWithDecodedLogs } from 'ethereum-types';
 import * as _ from 'lodash';
 
 import { constants } from './constants';
+import { web3Wrapper } from './web3_wrapper';
 
 const expect = chai.expect;
 
@@ -52,6 +55,48 @@ export function expectRevertOrAlwaysFailingTransactionAsync<T>(p: Promise<T>): P
 }
 
 /**
+ * Rejects if at least one the following conditions is not met:
+ * 1) The given Promise rejects with the given revert reason.
+ * 2) The given Promise rejects with an error containing "always failing transaction"
+ * 3) The given Promise fulfills with a txReceipt that has a status of 0 or '0', indicating the transaction failed.
+ * 4) The given Promise fulfills with a txHash and corresponding txReceipt has a status of 0 or '0'.
+ * @param p the Promise which is expected to reject
+ * @param reason a specific revert reason
+ * @returns a new Promise which will reject if the conditions are not met and
+ * otherwise resolve with no value.
+ */
+export async function expectRevertReasonOrAlwaysFailingTransactionAsync(
+    p: Promise<string | TransactionReceiptWithDecodedLogs | TransactionReceipt>,
+    reason: RevertReason,
+): Promise<void> {
+    return p
+        .then(async result => {
+            let txReceiptStatus: string | 0 | 1 | null;
+            if (typeof result === 'string') {
+                // Result is a txHash. We need to make a web3 call to get the receipt.
+                const txReceipt = await web3Wrapper.awaitTransactionMinedAsync(result);
+                txReceiptStatus = txReceipt.status;
+            } else if ('status' in result) {
+                // Result is a TransactionReceiptWithDecodedLogs or TransactionReceipt
+                // and status is a field of result.
+                txReceiptStatus = result.status;
+            } else {
+                throw new Error('Unexpected result type');
+            }
+            expect(_.toString(txReceiptStatus)).to.equal(
+                '0',
+                'transactionReceipt had a non-zero status, indicating success',
+            );
+        })
+        .catch(err => {
+            expect(err.message).to.satisfy(
+                (msg: string) => _.includes(msg, reason) || _.includes(msg, 'always failing transaction'),
+                `Expected ${reason} or 'always failing transaction' but error message was ${err.message}`,
+            );
+        });
+}
+
+/**
  * Rejects if the given Promise does not reject with a "revert" or "Contract
  * call failed" error.
  * @param p the Promise which is expected to reject
diff --git a/packages/contracts/test/utils/asset_wrapper.ts b/packages/contracts/test/utils/asset_wrapper.ts
new file mode 100644
index 000000000..402a7ab28
--- /dev/null
+++ b/packages/contracts/test/utils/asset_wrapper.ts
@@ -0,0 +1,216 @@
+import { assetProxyUtils } from '@0xproject/order-utils';
+import { AssetProxyId } from '@0xproject/types';
+import { BigNumber, errorUtils } from '@0xproject/utils';
+import * as _ from 'lodash';
+
+import { AbstractAssetWrapper } from './abstract_asset_wrapper';
+import { constants } from './constants';
+import { ERC20Wrapper } from './erc20_wrapper';
+import { ERC721Wrapper } from './erc721_wrapper';
+
+interface ProxyIdToAssetWrappers {
+    [proxyId: string]: AbstractAssetWrapper;
+}
+
+/**
+ * This class abstracts away the differences between ERC20 and ERC721 tokens so that
+ * the logic that uses it does not need to care what standard a token belongs to.
+ */
+export class AssetWrapper {
+    private _proxyIdToAssetWrappers: ProxyIdToAssetWrappers;
+    constructor(assetWrappers: AbstractAssetWrapper[]) {
+        this._proxyIdToAssetWrappers = {};
+        _.each(assetWrappers, assetWrapper => {
+            const proxyId = assetWrapper.getProxyId();
+            this._proxyIdToAssetWrappers[proxyId] = assetWrapper;
+        });
+    }
+    public async getBalanceAsync(userAddress: string, assetData: string): Promise<BigNumber> {
+        const proxyId = assetProxyUtils.decodeAssetDataId(assetData);
+        switch (proxyId) {
+            case AssetProxyId.ERC20: {
+                const erc20Wrapper = this._proxyIdToAssetWrappers[proxyId] as ERC20Wrapper;
+                const balance = await erc20Wrapper.getBalanceAsync(userAddress, assetData);
+                return balance;
+            }
+            case AssetProxyId.ERC721: {
+                const assetWrapper = this._proxyIdToAssetWrappers[proxyId] as ERC721Wrapper;
+                const assetProxyData = assetProxyUtils.decodeERC721AssetData(assetData);
+                const isOwner = await assetWrapper.isOwnerAsync(
+                    userAddress,
+                    assetProxyData.tokenAddress,
+                    assetProxyData.tokenId,
+                );
+                const balance = isOwner ? new BigNumber(1) : new BigNumber(0);
+                return balance;
+            }
+            default:
+                throw errorUtils.spawnSwitchErr('proxyId', proxyId);
+        }
+    }
+    public async setBalanceAsync(userAddress: string, assetData: string, desiredBalance: BigNumber): Promise<void> {
+        const proxyId = assetProxyUtils.decodeAssetDataId(assetData);
+        switch (proxyId) {
+            case AssetProxyId.ERC20: {
+                const erc20Wrapper = this._proxyIdToAssetWrappers[proxyId] as ERC20Wrapper;
+                await erc20Wrapper.setBalanceAsync(userAddress, assetData, desiredBalance);
+                return;
+            }
+            case AssetProxyId.ERC721: {
+                if (!desiredBalance.eq(0) && !desiredBalance.eq(1)) {
+                    throw new Error(`Balance for ERC721 token can only be set to 0 or 1. Got: ${desiredBalance}`);
+                }
+                const erc721Wrapper = this._proxyIdToAssetWrappers[proxyId] as ERC721Wrapper;
+                const assetProxyData = assetProxyUtils.decodeERC721AssetData(assetData);
+                const doesTokenExist = erc721Wrapper.doesTokenExistAsync(
+                    assetProxyData.tokenAddress,
+                    assetProxyData.tokenId,
+                );
+                if (!doesTokenExist && desiredBalance.eq(1)) {
+                    await erc721Wrapper.mintAsync(assetProxyData.tokenAddress, assetProxyData.tokenId, userAddress);
+                    return;
+                } else if (!doesTokenExist && desiredBalance.eq(0)) {
+                    return; // noop
+                }
+                const tokenOwner = await erc721Wrapper.ownerOfAsync(
+                    assetProxyData.tokenAddress,
+                    assetProxyData.tokenId,
+                );
+                if (userAddress !== tokenOwner && desiredBalance.eq(1)) {
+                    await erc721Wrapper.transferFromAsync(
+                        assetProxyData.tokenAddress,
+                        assetProxyData.tokenId,
+                        tokenOwner,
+                        userAddress,
+                    );
+                } else if (tokenOwner === userAddress && desiredBalance.eq(0)) {
+                    // Burn token
+                    await erc721Wrapper.burnAsync(assetProxyData.tokenAddress, assetProxyData.tokenId, userAddress);
+                    return;
+                } else if (
+                    (userAddress !== tokenOwner && desiredBalance.eq(0)) ||
+                    (tokenOwner === userAddress && desiredBalance.eq(1))
+                ) {
+                    return; // noop
+                }
+                break;
+            }
+            default:
+                throw errorUtils.spawnSwitchErr('proxyId', proxyId);
+        }
+    }
+    public async getProxyAllowanceAsync(userAddress: string, assetData: string): Promise<BigNumber> {
+        const proxyId = assetProxyUtils.decodeAssetDataId(assetData);
+        switch (proxyId) {
+            case AssetProxyId.ERC20: {
+                const erc20Wrapper = this._proxyIdToAssetWrappers[proxyId] as ERC20Wrapper;
+                const allowance = await erc20Wrapper.getProxyAllowanceAsync(userAddress, assetData);
+                return allowance;
+            }
+            case AssetProxyId.ERC721: {
+                const assetWrapper = this._proxyIdToAssetWrappers[proxyId] as ERC721Wrapper;
+                const erc721ProxyData = assetProxyUtils.decodeERC721AssetData(assetData);
+                const isProxyApprovedForAll = await assetWrapper.isProxyApprovedForAllAsync(
+                    userAddress,
+                    erc721ProxyData.tokenAddress,
+                );
+                if (isProxyApprovedForAll) {
+                    return constants.UNLIMITED_ALLOWANCE_IN_BASE_UNITS;
+                }
+
+                const isProxyApproved = await assetWrapper.isProxyApprovedAsync(
+                    erc721ProxyData.tokenAddress,
+                    erc721ProxyData.tokenId,
+                );
+                const allowance = isProxyApproved ? new BigNumber(1) : new BigNumber(0);
+                return allowance;
+            }
+            default:
+                throw errorUtils.spawnSwitchErr('proxyId', proxyId);
+        }
+    }
+    public async setProxyAllowanceAsync(
+        userAddress: string,
+        assetData: string,
+        desiredAllowance: BigNumber,
+    ): Promise<void> {
+        const proxyId = assetProxyUtils.decodeAssetDataId(assetData);
+        switch (proxyId) {
+            case AssetProxyId.ERC20: {
+                const erc20Wrapper = this._proxyIdToAssetWrappers[proxyId] as ERC20Wrapper;
+                await erc20Wrapper.setAllowanceAsync(userAddress, assetData, desiredAllowance);
+                return;
+            }
+            case AssetProxyId.ERC721: {
+                if (
+                    !desiredAllowance.eq(0) &&
+                    !desiredAllowance.eq(1) &&
+                    !desiredAllowance.eq(constants.UNLIMITED_ALLOWANCE_IN_BASE_UNITS)
+                ) {
+                    throw new Error(
+                        `Allowance for ERC721 token can only be set to 0, 1 or 2^256-1. Got: ${desiredAllowance}`,
+                    );
+                }
+                const erc721Wrapper = this._proxyIdToAssetWrappers[proxyId] as ERC721Wrapper;
+                const assetProxyData = assetProxyUtils.decodeERC721AssetData(assetData);
+
+                const doesTokenExist = await erc721Wrapper.doesTokenExistAsync(
+                    assetProxyData.tokenAddress,
+                    assetProxyData.tokenId,
+                );
+                if (!doesTokenExist) {
+                    throw new Error(
+                        `Cannot setProxyAllowance on non-existent token: ${assetProxyData.tokenAddress} ${
+                            assetProxyData.tokenId
+                        }`,
+                    );
+                }
+                const isProxyApprovedForAll = await erc721Wrapper.isProxyApprovedForAllAsync(
+                    userAddress,
+                    assetProxyData.tokenAddress,
+                );
+                if (!isProxyApprovedForAll && desiredAllowance.eq(constants.UNLIMITED_ALLOWANCE_IN_BASE_UNITS)) {
+                    const isApproved = true;
+                    await erc721Wrapper.approveProxyForAllAsync(
+                        assetProxyData.tokenAddress,
+                        assetProxyData.tokenId,
+                        isApproved,
+                    );
+                } else if (isProxyApprovedForAll && desiredAllowance.eq(0)) {
+                    const isApproved = false;
+                    await erc721Wrapper.approveProxyForAllAsync(
+                        assetProxyData.tokenAddress,
+                        assetProxyData.tokenId,
+                        isApproved,
+                    );
+                } else if (isProxyApprovedForAll && desiredAllowance.eq(constants.UNLIMITED_ALLOWANCE_IN_BASE_UNITS)) {
+                    return; // Noop
+                }
+
+                const isProxyApproved = await erc721Wrapper.isProxyApprovedAsync(
+                    assetProxyData.tokenAddress,
+                    assetProxyData.tokenId,
+                );
+                if (!isProxyApproved && desiredAllowance.eq(1)) {
+                    await erc721Wrapper.approveProxyAsync(assetProxyData.tokenAddress, assetProxyData.tokenId);
+                } else if (isProxyApproved && desiredAllowance.eq(0)) {
+                    // Remove approval
+                    await erc721Wrapper.approveAsync(
+                        constants.NULL_ADDRESS,
+                        assetProxyData.tokenAddress,
+                        assetProxyData.tokenId,
+                    );
+                } else if (
+                    (!isProxyApproved && desiredAllowance.eq(0)) ||
+                    (isProxyApproved && desiredAllowance.eq(1))
+                ) {
+                    return; // noop
+                }
+
+                break;
+            }
+            default:
+                throw errorUtils.spawnSwitchErr('proxyId', proxyId);
+        }
+    }
+}
diff --git a/packages/contracts/src/utils/chai_setup.ts b/packages/contracts/test/utils/chai_setup.ts
index 1a8733093..1a8733093 100644
--- a/packages/contracts/src/utils/chai_setup.ts
+++ b/packages/contracts/test/utils/chai_setup.ts
diff --git a/packages/contracts/src/utils/constants.ts b/packages/contracts/test/utils/constants.ts
index f21b8c7a0..8e68f376d 100644
--- a/packages/contracts/src/utils/constants.ts
+++ b/packages/contracts/test/utils/constants.ts
@@ -19,19 +19,6 @@ const TESTRPC_PRIVATE_KEYS_STRINGS = [
 export const constants = {
     INVALID_OPCODE: 'invalid opcode',
     REVERT: 'revert',
-    LIB_BYTES_GREATER_THAN_ZERO_LENGTH_REQUIRED: 'GREATER_THAN_ZERO_LENGTH_REQUIRED',
-    LIB_BYTES_GREATER_OR_EQUAL_TO_4_LENGTH_REQUIRED: 'GREATER_OR_EQUAL_TO_4_LENGTH_REQUIRED',
-    LIB_BYTES_GREATER_OR_EQUAL_TO_20_LENGTH_REQUIRED: 'GREATER_OR_EQUAL_TO_20_LENGTH_REQUIRED',
-    LIB_BYTES_GREATER_OR_EQUAL_TO_32_LENGTH_REQUIRED: 'GREATER_OR_EQUAL_TO_32_LENGTH_REQUIRED',
-    LIB_BYTES_GREATER_OR_EQUAL_TO_NESTED_BYTES_LENGTH_REQUIRED: 'GREATER_OR_EQUAL_TO_NESTED_BYTES_LENGTH_REQUIRED',
-    LIB_BYTES_GREATER_OR_EQUAL_TO_SOURCE_BYTES_LENGTH_REQUIRED: 'GREATER_OR_EQUAL_TO_SOURCE_BYTES_LENGTH_REQUIRED',
-    ERC20_INSUFFICIENT_BALANCE: 'Insufficient balance to complete transfer.',
-    ERC20_INSUFFICIENT_ALLOWANCE: 'Insufficient allowance to complete transfer.',
-    EXCHANGE_LENGTH_GREATER_THAN_0_REQUIRED: 'LENGTH_GREATER_THAN_0_REQUIRED',
-    EXCHANGE_SIGNATURE_UNSUPPORTED: 'SIGNATURE_UNSUPPORTED',
-    EXCHANGE_SIGNATURE_ILLEGAL: 'SIGNATURE_ILLEGAL',
-    EXCHANGE_LENGTH_0_REQUIRED: 'LENGTH_0_REQUIRED',
-    EXCHANGE_LENGTH_65_REQUIRED: 'LENGTH_65_REQUIRED',
     TESTRPC_NETWORK_ID: 50,
     // Note(albrow): In practice V8 and most other engines limit the minimum
     // interval for setInterval to 10ms. We still set it to 0 here in order to
@@ -40,6 +27,7 @@ export const constants = {
     MAX_ETHERTOKEN_WITHDRAW_GAS: 43000,
     MAX_TOKEN_TRANSFERFROM_GAS: 80000,
     MAX_TOKEN_APPROVE_GAS: 60000,
+    TRANSFER_FROM_GAS: 150000,
     DUMMY_TOKEN_NAME: '',
     DUMMY_TOKEN_SYMBOL: '',
     DUMMY_TOKEN_DECIMALS: new BigNumber(18),
diff --git a/packages/contracts/test/utils/core_combinatorial_utils.ts b/packages/contracts/test/utils/core_combinatorial_utils.ts
new file mode 100644
index 000000000..718be17e0
--- /dev/null
+++ b/packages/contracts/test/utils/core_combinatorial_utils.ts
@@ -0,0 +1,802 @@
+import {
+    assetProxyUtils,
+    BalanceAndProxyAllowanceLazyStore,
+    ExchangeTransferSimulator,
+    orderHashUtils,
+    OrderStateUtils,
+    OrderValidationUtils,
+} from '@0xproject/order-utils';
+import { AssetProxyId, RevertReason, SignatureType, SignedOrder } from '@0xproject/types';
+import { BigNumber, errorUtils, logUtils } from '@0xproject/utils';
+import { Web3Wrapper } from '@0xproject/web3-wrapper';
+import * as chai from 'chai';
+import { LogWithDecodedArgs, Provider, TxData } from 'ethereum-types';
+import * as _ from 'lodash';
+import 'make-promises-safe';
+
+import { ExchangeContract, FillContractEventArgs } from '../../generated_contract_wrappers/exchange';
+
+import { artifacts } from './artifacts';
+import { expectRevertReasonOrAlwaysFailingTransactionAsync } from './assertions';
+import { AssetWrapper } from './asset_wrapper';
+import { chaiSetup } from './chai_setup';
+import { constants } from './constants';
+import { ERC20Wrapper } from './erc20_wrapper';
+import { ERC721Wrapper } from './erc721_wrapper';
+import { ExchangeWrapper } from './exchange_wrapper';
+import { OrderFactoryFromScenario } from './order_factory_from_scenario';
+import { orderUtils } from './order_utils';
+import { signingUtils } from './signing_utils';
+import { SimpleAssetBalanceAndProxyAllowanceFetcher } from './simple_asset_balance_and_proxy_allowance_fetcher';
+import { SimpleOrderFilledCancelledFetcher } from './simple_order_filled_cancelled_fetcher';
+import {
+    AllowanceAmountScenario,
+    AssetDataScenario,
+    BalanceAmountScenario,
+    ExpirationTimeSecondsScenario,
+    FeeRecipientAddressScenario,
+    FillScenario,
+    OrderAssetAmountScenario,
+    TakerAssetFillAmountScenario,
+    TakerScenario,
+    TraderStateScenario,
+} from './types';
+
+chaiSetup.configure();
+const expect = chai.expect;
+
+/**
+ * Instantiates a new instance of CoreCombinatorialUtils. Since this method has some
+ * required async setup, a factory method is required.
+ * @param web3Wrapper Web3Wrapper instance
+ * @param txDefaults Default Ethereum tx options
+ * @return CoreCombinatorialUtils instance
+ */
+export async function coreCombinatorialUtilsFactoryAsync(
+    web3Wrapper: Web3Wrapper,
+    txDefaults: Partial<TxData>,
+): Promise<CoreCombinatorialUtils> {
+    const accounts = await web3Wrapper.getAvailableAddressesAsync();
+    const userAddresses = _.slice(accounts, 0, 5);
+    const [ownerAddress, makerAddress, takerAddress] = userAddresses;
+    const makerPrivateKey = constants.TESTRPC_PRIVATE_KEYS[userAddresses.indexOf(makerAddress)];
+
+    const provider = web3Wrapper.getProvider();
+    const erc20Wrapper = new ERC20Wrapper(provider, userAddresses, ownerAddress);
+    const erc721Wrapper = new ERC721Wrapper(provider, userAddresses, ownerAddress);
+
+    const erc20EighteenDecimalTokenCount = 3;
+    const eighteenDecimals = new BigNumber(18);
+    const [
+        erc20EighteenDecimalTokenA,
+        erc20EighteenDecimalTokenB,
+        zrxToken,
+    ] = await erc20Wrapper.deployDummyTokensAsync(erc20EighteenDecimalTokenCount, eighteenDecimals);
+    const zrxAssetData = assetProxyUtils.encodeERC20AssetData(zrxToken.address);
+
+    const erc20FiveDecimalTokenCount = 2;
+    const fiveDecimals = new BigNumber(18);
+    const [erc20FiveDecimalTokenA, erc20FiveDecimalTokenB] = await erc20Wrapper.deployDummyTokensAsync(
+        erc20FiveDecimalTokenCount,
+        fiveDecimals,
+    );
+    const erc20Proxy = await erc20Wrapper.deployProxyAsync();
+    await erc20Wrapper.setBalancesAndAllowancesAsync();
+
+    const [erc721Token] = await erc721Wrapper.deployDummyTokensAsync();
+    const erc721Proxy = await erc721Wrapper.deployProxyAsync();
+    await erc721Wrapper.setBalancesAndAllowancesAsync();
+    const erc721Balances = await erc721Wrapper.getBalancesAsync();
+
+    const assetWrapper = new AssetWrapper([erc20Wrapper, erc721Wrapper]);
+
+    const exchangeContract = await ExchangeContract.deployFrom0xArtifactAsync(
+        artifacts.Exchange,
+        provider,
+        txDefaults,
+        zrxAssetData,
+    );
+    const exchangeWrapper = new ExchangeWrapper(exchangeContract, provider);
+    await exchangeWrapper.registerAssetProxyAsync(erc20Proxy.address, ownerAddress);
+    await exchangeWrapper.registerAssetProxyAsync(erc721Proxy.address, ownerAddress);
+
+    await web3Wrapper.awaitTransactionSuccessAsync(
+        await erc20Proxy.addAuthorizedAddress.sendTransactionAsync(exchangeContract.address, {
+            from: ownerAddress,
+        }),
+        constants.AWAIT_TRANSACTION_MINED_MS,
+    );
+    await web3Wrapper.awaitTransactionSuccessAsync(
+        await erc721Proxy.addAuthorizedAddress.sendTransactionAsync(exchangeContract.address, {
+            from: ownerAddress,
+        }),
+        constants.AWAIT_TRANSACTION_MINED_MS,
+    );
+
+    const orderFactory = new OrderFactoryFromScenario(
+        userAddresses,
+        zrxToken.address,
+        [erc20EighteenDecimalTokenA.address, erc20EighteenDecimalTokenB.address],
+        [erc20FiveDecimalTokenA.address, erc20FiveDecimalTokenB.address],
+        erc721Token,
+        erc721Balances,
+        exchangeContract.address,
+    );
+
+    const coreCombinatorialUtils = new CoreCombinatorialUtils(
+        orderFactory,
+        ownerAddress,
+        makerAddress,
+        makerPrivateKey,
+        takerAddress,
+        zrxAssetData,
+        exchangeWrapper,
+        assetWrapper,
+    );
+    return coreCombinatorialUtils;
+}
+
+export class CoreCombinatorialUtils {
+    public orderFactory: OrderFactoryFromScenario;
+    public ownerAddress: string;
+    public makerAddress: string;
+    public makerPrivateKey: Buffer;
+    public takerAddress: string;
+    public zrxAssetData: string;
+    public exchangeWrapper: ExchangeWrapper;
+    public assetWrapper: AssetWrapper;
+    public static generateFillOrderCombinations(): FillScenario[] {
+        const takerScenarios = [TakerScenario.Unspecified];
+        const feeRecipientScenarios = [FeeRecipientAddressScenario.EthUserAddress];
+        const makerAssetAmountScenario = [OrderAssetAmountScenario.Large];
+        const takerAssetAmountScenario = [OrderAssetAmountScenario.Large];
+        const makerFeeScenario = [OrderAssetAmountScenario.Large];
+        const takerFeeScenario = [OrderAssetAmountScenario.Large];
+        const expirationTimeSecondsScenario = [ExpirationTimeSecondsScenario.InFuture];
+        const makerAssetDataScenario = [
+            AssetDataScenario.ERC20FiveDecimals,
+            AssetDataScenario.ERC20NonZRXEighteenDecimals,
+            AssetDataScenario.ERC721,
+            AssetDataScenario.ZRXFeeToken,
+        ];
+        const takerAssetDataScenario = [
+            AssetDataScenario.ERC20FiveDecimals,
+            AssetDataScenario.ERC20NonZRXEighteenDecimals,
+            AssetDataScenario.ERC721,
+            AssetDataScenario.ZRXFeeToken,
+        ];
+        const takerAssetFillAmountScenario = [TakerAssetFillAmountScenario.ExactlyRemainingFillableTakerAssetAmount];
+        const fillScenarioArrays = CoreCombinatorialUtils._getAllCombinations([
+            takerScenarios,
+            feeRecipientScenarios,
+            makerAssetAmountScenario,
+            takerAssetAmountScenario,
+            makerFeeScenario,
+            takerFeeScenario,
+            expirationTimeSecondsScenario,
+            makerAssetDataScenario,
+            takerAssetDataScenario,
+            takerAssetFillAmountScenario,
+        ]);
+
+        const fillScenarios = _.map(fillScenarioArrays, fillScenarioArray => {
+            const fillScenario: FillScenario = {
+                orderScenario: {
+                    takerScenario: fillScenarioArray[0] as TakerScenario,
+                    feeRecipientScenario: fillScenarioArray[1] as FeeRecipientAddressScenario,
+                    makerAssetAmountScenario: fillScenarioArray[2] as OrderAssetAmountScenario,
+                    takerAssetAmountScenario: fillScenarioArray[3] as OrderAssetAmountScenario,
+                    makerFeeScenario: fillScenarioArray[4] as OrderAssetAmountScenario,
+                    takerFeeScenario: fillScenarioArray[5] as OrderAssetAmountScenario,
+                    expirationTimeSecondsScenario: fillScenarioArray[6] as ExpirationTimeSecondsScenario,
+                    makerAssetDataScenario: fillScenarioArray[7] as AssetDataScenario,
+                    takerAssetDataScenario: fillScenarioArray[8] as AssetDataScenario,
+                },
+                takerAssetFillAmountScenario: fillScenarioArray[9] as TakerAssetFillAmountScenario,
+                makerStateScenario: {
+                    traderAssetBalance: BalanceAmountScenario.Higher,
+                    traderAssetAllowance: AllowanceAmountScenario.Higher,
+                    zrxFeeBalance: BalanceAmountScenario.Higher,
+                    zrxFeeAllowance: AllowanceAmountScenario.Higher,
+                },
+                takerStateScenario: {
+                    traderAssetBalance: BalanceAmountScenario.Higher,
+                    traderAssetAllowance: AllowanceAmountScenario.Higher,
+                    zrxFeeBalance: BalanceAmountScenario.Higher,
+                    zrxFeeAllowance: AllowanceAmountScenario.Higher,
+                },
+            };
+            return fillScenario;
+        });
+
+        return fillScenarios;
+    }
+    /**
+     * Recursive implementation of generating all combinations of the supplied
+     * string-containing arrays.
+     */
+    private static _getAllCombinations(arrays: string[][]): string[][] {
+        // Base case
+        if (arrays.length === 1) {
+            const remainingValues = _.map(arrays[0], val => {
+                return [val];
+            });
+            return remainingValues;
+        } else {
+            const result = [];
+            const restOfArrays = arrays.slice(1);
+            const allCombinationsOfRemaining = CoreCombinatorialUtils._getAllCombinations(restOfArrays); // recur with the rest of array
+            // tslint:disable:prefer-for-of
+            for (let i = 0; i < allCombinationsOfRemaining.length; i++) {
+                for (let j = 0; j < arrays[0].length; j++) {
+                    result.push([arrays[0][j], ...allCombinationsOfRemaining[i]]);
+                }
+            }
+            // tslint:enable:prefer-for-of
+            return result;
+        }
+    }
+    constructor(
+        orderFactory: OrderFactoryFromScenario,
+        ownerAddress: string,
+        makerAddress: string,
+        makerPrivateKey: Buffer,
+        takerAddress: string,
+        zrxAssetData: string,
+        exchangeWrapper: ExchangeWrapper,
+        assetWrapper: AssetWrapper,
+    ) {
+        this.orderFactory = orderFactory;
+        this.ownerAddress = ownerAddress;
+        this.makerAddress = makerAddress;
+        this.makerPrivateKey = makerPrivateKey;
+        this.takerAddress = takerAddress;
+        this.zrxAssetData = zrxAssetData;
+        this.exchangeWrapper = exchangeWrapper;
+        this.assetWrapper = assetWrapper;
+    }
+    public async testFillOrderScenarioAsync(
+        provider: Provider,
+        fillScenario: FillScenario,
+        isVerbose: boolean = false,
+    ): Promise<void> {
+        // 1. Generate order
+        const order = this.orderFactory.generateOrder(fillScenario.orderScenario);
+
+        // 2. Sign order
+        const orderHashBuff = orderHashUtils.getOrderHashBuffer(order);
+        const signature = signingUtils.signMessage(orderHashBuff, this.makerPrivateKey, SignatureType.EthSign);
+        const signedOrder = {
+            ...order,
+            signature: `0x${signature.toString('hex')}`,
+        };
+
+        const balanceAndProxyAllowanceFetcher = new SimpleAssetBalanceAndProxyAllowanceFetcher(this.assetWrapper);
+        const orderFilledCancelledFetcher = new SimpleOrderFilledCancelledFetcher(
+            this.exchangeWrapper,
+            this.zrxAssetData,
+        );
+
+        // 3. Figure out fill amount
+        const takerAssetFillAmount = await this._getTakerAssetFillAmountAsync(
+            signedOrder,
+            fillScenario.takerAssetFillAmountScenario,
+            balanceAndProxyAllowanceFetcher,
+            orderFilledCancelledFetcher,
+        );
+
+        // 4. Permutate the maker and taker balance/allowance scenarios
+        await this._modifyTraderStateAsync(
+            fillScenario.makerStateScenario,
+            fillScenario.takerStateScenario,
+            signedOrder,
+            takerAssetFillAmount,
+        );
+
+        // 5. If I fill it by X, what are the resulting balances/allowances/filled amounts expected?
+        const orderValidationUtils = new OrderValidationUtils(orderFilledCancelledFetcher);
+        const lazyStore = new BalanceAndProxyAllowanceLazyStore(balanceAndProxyAllowanceFetcher);
+        const exchangeTransferSimulator = new ExchangeTransferSimulator(lazyStore);
+
+        let fillRevertReasonIfExists;
+        try {
+            await orderValidationUtils.validateFillOrderThrowIfInvalidAsync(
+                exchangeTransferSimulator,
+                provider,
+                signedOrder,
+                takerAssetFillAmount,
+                this.takerAddress,
+                this.zrxAssetData,
+            );
+            if (isVerbose) {
+                logUtils.log(`Expecting fillOrder to succeed.`);
+            }
+        } catch (err) {
+            fillRevertReasonIfExists = err.message;
+            if (isVerbose) {
+                logUtils.log(`Expecting fillOrder to fail with:`);
+                logUtils.log(err);
+            }
+        }
+
+        // 6. Fill the order
+        await this._fillOrderAndAssertOutcomeAsync(
+            signedOrder,
+            takerAssetFillAmount,
+            lazyStore,
+            fillRevertReasonIfExists,
+        );
+    }
+    private async _fillOrderAndAssertOutcomeAsync(
+        signedOrder: SignedOrder,
+        takerAssetFillAmount: BigNumber,
+        lazyStore: BalanceAndProxyAllowanceLazyStore,
+        fillRevertReasonIfExists: RevertReason | undefined,
+    ): Promise<void> {
+        if (!_.isUndefined(fillRevertReasonIfExists)) {
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
+                this.exchangeWrapper.fillOrderAsync(signedOrder, this.takerAddress, { takerAssetFillAmount }),
+                fillRevertReasonIfExists,
+            );
+        }
+
+        const makerAddress = signedOrder.makerAddress;
+        const makerAssetData = signedOrder.makerAssetData;
+        const takerAssetData = signedOrder.takerAssetData;
+        const feeRecipient = signedOrder.feeRecipientAddress;
+
+        const expMakerAssetBalanceOfMaker = await lazyStore.getBalanceAsync(makerAssetData, makerAddress);
+        const expMakerAssetAllowanceOfMaker = await lazyStore.getProxyAllowanceAsync(makerAssetData, makerAddress);
+        const expTakerAssetBalanceOfMaker = await lazyStore.getBalanceAsync(takerAssetData, makerAddress);
+        const expZRXAssetBalanceOfMaker = await lazyStore.getBalanceAsync(this.zrxAssetData, makerAddress);
+        const expZRXAssetAllowanceOfMaker = await lazyStore.getProxyAllowanceAsync(this.zrxAssetData, makerAddress);
+        const expTakerAssetBalanceOfTaker = await lazyStore.getBalanceAsync(takerAssetData, this.takerAddress);
+        const expTakerAssetAllowanceOfTaker = await lazyStore.getProxyAllowanceAsync(takerAssetData, this.takerAddress);
+        const expMakerAssetBalanceOfTaker = await lazyStore.getBalanceAsync(makerAssetData, this.takerAddress);
+        const expZRXAssetBalanceOfTaker = await lazyStore.getBalanceAsync(this.zrxAssetData, this.takerAddress);
+        const expZRXAssetAllowanceOfTaker = await lazyStore.getProxyAllowanceAsync(
+            this.zrxAssetData,
+            this.takerAddress,
+        );
+        const expZRXAssetBalanceOfFeeRecipient = await lazyStore.getBalanceAsync(this.zrxAssetData, feeRecipient);
+
+        const orderHash = orderHashUtils.getOrderHashHex(signedOrder);
+        const alreadyFilledTakerAmount = await this.exchangeWrapper.getTakerAssetFilledAmountAsync(orderHash);
+        const remainingTakerAmountToFill = signedOrder.takerAssetAmount.minus(alreadyFilledTakerAmount);
+        const expFilledTakerAmount = takerAssetFillAmount.gt(remainingTakerAmountToFill)
+            ? remainingTakerAmountToFill
+            : alreadyFilledTakerAmount.add(takerAssetFillAmount);
+
+        const expFilledMakerAmount = orderUtils.getPartialAmount(
+            expFilledTakerAmount,
+            signedOrder.takerAssetAmount,
+            signedOrder.makerAssetAmount,
+        );
+
+        // - Let's fill the order!
+        const txReceipt = await this.exchangeWrapper.fillOrderAsync(signedOrder, this.takerAddress, {
+            takerAssetFillAmount,
+        });
+
+        const actFilledTakerAmount = await this.exchangeWrapper.getTakerAssetFilledAmountAsync(orderHash);
+        expect(actFilledTakerAmount).to.be.bignumber.equal(expFilledTakerAmount, 'filledTakerAmount');
+
+        expect(txReceipt.logs.length).to.be.equal(1, 'logs length');
+        // tslint:disable-next-line:no-unnecessary-type-assertion
+        const log = txReceipt.logs[0] as LogWithDecodedArgs<FillContractEventArgs>;
+        expect(log.args.makerAddress).to.be.equal(makerAddress, 'log.args.makerAddress');
+        expect(log.args.takerAddress).to.be.equal(this.takerAddress, 'log.args.this.takerAddress');
+        expect(log.args.feeRecipientAddress).to.be.equal(feeRecipient, 'log.args.feeRecipientAddress');
+        expect(log.args.makerAssetFilledAmount).to.be.bignumber.equal(
+            expFilledMakerAmount,
+            'log.args.makerAssetFilledAmount',
+        );
+        expect(log.args.takerAssetFilledAmount).to.be.bignumber.equal(
+            expFilledTakerAmount,
+            'log.args.takerAssetFilledAmount',
+        );
+        const expMakerFeePaid = orderUtils.getPartialAmount(
+            expFilledTakerAmount,
+            signedOrder.takerAssetAmount,
+            signedOrder.makerFee,
+        );
+        expect(log.args.makerFeePaid).to.be.bignumber.equal(expMakerFeePaid, 'log.args.makerFeePaid');
+        const expTakerFeePaid = orderUtils.getPartialAmount(
+            expFilledTakerAmount,
+            signedOrder.takerAssetAmount,
+            signedOrder.takerFee,
+        );
+        expect(log.args.takerFeePaid).to.be.bignumber.equal(expTakerFeePaid, 'logs.args.takerFeePaid');
+        expect(log.args.orderHash).to.be.equal(orderHash, 'log.args.orderHash');
+        expect(log.args.makerAssetData).to.be.equal(makerAssetData, 'log.args.makerAssetData');
+        expect(log.args.takerAssetData).to.be.equal(takerAssetData, 'log.args.takerAssetData');
+
+        const actMakerAssetBalanceOfMaker = await this.assetWrapper.getBalanceAsync(makerAddress, makerAssetData);
+        expect(actMakerAssetBalanceOfMaker).to.be.bignumber.equal(
+            expMakerAssetBalanceOfMaker,
+            'makerAssetBalanceOfMaker',
+        );
+
+        const actMakerAssetAllowanceOfMaker = await this.assetWrapper.getProxyAllowanceAsync(
+            makerAddress,
+            makerAssetData,
+        );
+        expect(actMakerAssetAllowanceOfMaker).to.be.bignumber.equal(
+            expMakerAssetAllowanceOfMaker,
+            'makerAssetAllowanceOfMaker',
+        );
+
+        const actTakerAssetBalanceOfMaker = await this.assetWrapper.getBalanceAsync(makerAddress, takerAssetData);
+        expect(actTakerAssetBalanceOfMaker).to.be.bignumber.equal(
+            expTakerAssetBalanceOfMaker,
+            'takerAssetBalanceOfMaker',
+        );
+
+        const actZRXAssetBalanceOfMaker = await this.assetWrapper.getBalanceAsync(makerAddress, this.zrxAssetData);
+        expect(actZRXAssetBalanceOfMaker).to.be.bignumber.equal(expZRXAssetBalanceOfMaker, 'ZRXAssetBalanceOfMaker');
+
+        const actZRXAssetAllowanceOfMaker = await this.assetWrapper.getProxyAllowanceAsync(
+            makerAddress,
+            this.zrxAssetData,
+        );
+        expect(actZRXAssetAllowanceOfMaker).to.be.bignumber.equal(
+            expZRXAssetAllowanceOfMaker,
+            'ZRXAssetAllowanceOfMaker',
+        );
+
+        const actTakerAssetBalanceOfTaker = await this.assetWrapper.getBalanceAsync(this.takerAddress, takerAssetData);
+        expect(actTakerAssetBalanceOfTaker).to.be.bignumber.equal(
+            expTakerAssetBalanceOfTaker,
+            'TakerAssetBalanceOfTaker',
+        );
+
+        const actTakerAssetAllowanceOfTaker = await this.assetWrapper.getProxyAllowanceAsync(
+            this.takerAddress,
+            takerAssetData,
+        );
+
+        expect(actTakerAssetAllowanceOfTaker).to.be.bignumber.equal(
+            expTakerAssetAllowanceOfTaker,
+            'TakerAssetAllowanceOfTaker',
+        );
+
+        const actMakerAssetBalanceOfTaker = await this.assetWrapper.getBalanceAsync(this.takerAddress, makerAssetData);
+        expect(actMakerAssetBalanceOfTaker).to.be.bignumber.equal(
+            expMakerAssetBalanceOfTaker,
+            'MakerAssetBalanceOfTaker',
+        );
+
+        const actZRXAssetBalanceOfTaker = await this.assetWrapper.getBalanceAsync(this.takerAddress, this.zrxAssetData);
+        expect(actZRXAssetBalanceOfTaker).to.be.bignumber.equal(expZRXAssetBalanceOfTaker, 'ZRXAssetBalanceOfTaker');
+
+        const actZRXAssetAllowanceOfTaker = await this.assetWrapper.getProxyAllowanceAsync(
+            this.takerAddress,
+            this.zrxAssetData,
+        );
+        expect(actZRXAssetAllowanceOfTaker).to.be.bignumber.equal(
+            expZRXAssetAllowanceOfTaker,
+            'ZRXAssetAllowanceOfTaker',
+        );
+
+        const actZRXAssetBalanceOfFeeRecipient = await this.assetWrapper.getBalanceAsync(
+            feeRecipient,
+            this.zrxAssetData,
+        );
+        expect(actZRXAssetBalanceOfFeeRecipient).to.be.bignumber.equal(
+            expZRXAssetBalanceOfFeeRecipient,
+            'ZRXAssetBalanceOfFeeRecipient',
+        );
+    }
+    private async _getTakerAssetFillAmountAsync(
+        signedOrder: SignedOrder,
+        takerAssetFillAmountScenario: TakerAssetFillAmountScenario,
+        balanceAndProxyAllowanceFetcher: SimpleAssetBalanceAndProxyAllowanceFetcher,
+        orderFilledCancelledFetcher: SimpleOrderFilledCancelledFetcher,
+    ): Promise<BigNumber> {
+        const orderStateUtils = new OrderStateUtils(balanceAndProxyAllowanceFetcher, orderFilledCancelledFetcher);
+        const fillableTakerAssetAmount = await orderStateUtils.getMaxFillableTakerAssetAmountAsync(
+            signedOrder,
+            this.takerAddress,
+        );
+
+        let takerAssetFillAmount;
+        switch (takerAssetFillAmountScenario) {
+            case TakerAssetFillAmountScenario.Zero:
+                takerAssetFillAmount = new BigNumber(0);
+                break;
+
+            case TakerAssetFillAmountScenario.ExactlyRemainingFillableTakerAssetAmount:
+                takerAssetFillAmount = fillableTakerAssetAmount;
+                break;
+
+            case TakerAssetFillAmountScenario.GreaterThanRemainingFillableTakerAssetAmount:
+                takerAssetFillAmount = fillableTakerAssetAmount.add(1);
+                break;
+
+            case TakerAssetFillAmountScenario.LessThanRemainingFillableTakerAssetAmount:
+                const takerAssetProxyId = assetProxyUtils.decodeAssetDataId(signedOrder.takerAssetData);
+                const makerAssetProxyId = assetProxyUtils.decodeAssetDataId(signedOrder.makerAssetData);
+                const isEitherAssetERC721 =
+                    takerAssetProxyId === AssetProxyId.ERC721 || makerAssetProxyId === AssetProxyId.ERC721;
+                if (isEitherAssetERC721) {
+                    throw new Error(
+                        'Cannot test `TakerAssetFillAmountScenario.LessThanRemainingFillableTakerAssetAmount` together with ERC721 assets since orders involving ERC721 must always be filled exactly.',
+                    );
+                }
+                takerAssetFillAmount = fillableTakerAssetAmount.div(2).floor();
+                break;
+
+            default:
+                throw errorUtils.spawnSwitchErr('TakerAssetFillAmountScenario', takerAssetFillAmountScenario);
+        }
+
+        return takerAssetFillAmount;
+    }
+    private async _modifyTraderStateAsync(
+        makerStateScenario: TraderStateScenario,
+        takerStateScenario: TraderStateScenario,
+        signedOrder: SignedOrder,
+        takerAssetFillAmount: BigNumber,
+    ): Promise<void> {
+        const makerAssetFillAmount = orderUtils.getPartialAmount(
+            takerAssetFillAmount,
+            signedOrder.takerAssetAmount,
+            signedOrder.makerAssetAmount,
+        );
+        switch (makerStateScenario.traderAssetBalance) {
+            case BalanceAmountScenario.Higher:
+                break; // Noop since this is already the default
+
+            case BalanceAmountScenario.TooLow:
+                if (makerAssetFillAmount.eq(0)) {
+                    throw new Error(`Cannot set makerAssetBalanceOfMaker TooLow if makerAssetFillAmount is 0`);
+                }
+                const tooLowBalance = makerAssetFillAmount.minus(1);
+                await this.assetWrapper.setBalanceAsync(
+                    signedOrder.makerAddress,
+                    signedOrder.makerAssetData,
+                    tooLowBalance,
+                );
+                break;
+
+            case BalanceAmountScenario.Exact:
+                const exactBalance = makerAssetFillAmount;
+                await this.assetWrapper.setBalanceAsync(
+                    signedOrder.makerAddress,
+                    signedOrder.makerAssetData,
+                    exactBalance,
+                );
+                break;
+
+            default:
+                throw errorUtils.spawnSwitchErr(
+                    'makerStateScenario.traderAssetBalance',
+                    makerStateScenario.traderAssetBalance,
+                );
+        }
+
+        const makerFee = orderUtils.getPartialAmount(
+            takerAssetFillAmount,
+            signedOrder.takerAssetAmount,
+            signedOrder.makerFee,
+        );
+        switch (makerStateScenario.zrxFeeBalance) {
+            case BalanceAmountScenario.Higher:
+                break; // Noop since this is already the default
+
+            case BalanceAmountScenario.TooLow:
+                if (makerFee.eq(0)) {
+                    throw new Error(`Cannot set zrxAsserBalanceOfMaker TooLow if makerFee is 0`);
+                }
+                const tooLowBalance = makerFee.minus(1);
+                await this.assetWrapper.setBalanceAsync(signedOrder.makerAddress, this.zrxAssetData, tooLowBalance);
+                break;
+
+            case BalanceAmountScenario.Exact:
+                const exactBalance = makerFee;
+                await this.assetWrapper.setBalanceAsync(signedOrder.makerAddress, this.zrxAssetData, exactBalance);
+                break;
+
+            default:
+                throw errorUtils.spawnSwitchErr('makerStateScenario.zrxFeeBalance', makerStateScenario.zrxFeeBalance);
+        }
+
+        switch (makerStateScenario.traderAssetAllowance) {
+            case AllowanceAmountScenario.Higher:
+                break; // Noop since this is already the default
+
+            case AllowanceAmountScenario.TooLow:
+                const tooLowAllowance = makerAssetFillAmount.minus(1);
+                await this.assetWrapper.setProxyAllowanceAsync(
+                    signedOrder.makerAddress,
+                    signedOrder.makerAssetData,
+                    tooLowAllowance,
+                );
+                break;
+
+            case AllowanceAmountScenario.Exact:
+                const exactAllowance = makerAssetFillAmount;
+                await this.assetWrapper.setProxyAllowanceAsync(
+                    signedOrder.makerAddress,
+                    signedOrder.makerAssetData,
+                    exactAllowance,
+                );
+                break;
+
+            case AllowanceAmountScenario.Unlimited:
+                await this.assetWrapper.setProxyAllowanceAsync(
+                    signedOrder.makerAddress,
+                    signedOrder.makerAssetData,
+                    constants.UNLIMITED_ALLOWANCE_IN_BASE_UNITS,
+                );
+                break;
+
+            default:
+                throw errorUtils.spawnSwitchErr(
+                    'makerStateScenario.traderAssetAllowance',
+                    makerStateScenario.traderAssetAllowance,
+                );
+        }
+
+        switch (makerStateScenario.zrxFeeAllowance) {
+            case AllowanceAmountScenario.Higher:
+                break; // Noop since this is already the default
+
+            case AllowanceAmountScenario.TooLow:
+                const tooLowAllowance = makerFee.minus(1);
+                await this.assetWrapper.setProxyAllowanceAsync(
+                    signedOrder.makerAddress,
+                    this.zrxAssetData,
+                    tooLowAllowance,
+                );
+                break;
+
+            case AllowanceAmountScenario.Exact:
+                const exactAllowance = makerFee;
+                await this.assetWrapper.setProxyAllowanceAsync(
+                    signedOrder.makerAddress,
+                    this.zrxAssetData,
+                    exactAllowance,
+                );
+                break;
+
+            case AllowanceAmountScenario.Unlimited:
+                await this.assetWrapper.setProxyAllowanceAsync(
+                    signedOrder.makerAddress,
+                    this.zrxAssetData,
+                    constants.UNLIMITED_ALLOWANCE_IN_BASE_UNITS,
+                );
+                break;
+
+            default:
+                throw errorUtils.spawnSwitchErr(
+                    'makerStateScenario.zrxFeeAllowance',
+                    makerStateScenario.zrxFeeAllowance,
+                );
+        }
+
+        switch (takerStateScenario.traderAssetBalance) {
+            case BalanceAmountScenario.Higher:
+                break; // Noop since this is already the default
+
+            case BalanceAmountScenario.TooLow:
+                if (takerAssetFillAmount.eq(0)) {
+                    throw new Error(`Cannot set takerAssetBalanceOfTaker TooLow if takerAssetFillAmount is 0`);
+                }
+                const tooLowBalance = takerAssetFillAmount.minus(1);
+                await this.assetWrapper.setBalanceAsync(this.takerAddress, signedOrder.takerAssetData, tooLowBalance);
+                break;
+
+            case BalanceAmountScenario.Exact:
+                const exactBalance = takerAssetFillAmount;
+                await this.assetWrapper.setBalanceAsync(this.takerAddress, signedOrder.takerAssetData, exactBalance);
+                break;
+
+            default:
+                throw errorUtils.spawnSwitchErr(
+                    'takerStateScenario.traderAssetBalance',
+                    takerStateScenario.traderAssetBalance,
+                );
+        }
+
+        const takerFee = orderUtils.getPartialAmount(
+            takerAssetFillAmount,
+            signedOrder.takerAssetAmount,
+            signedOrder.takerFee,
+        );
+        switch (takerStateScenario.zrxFeeBalance) {
+            case BalanceAmountScenario.Higher:
+                break; // Noop since this is already the default
+
+            case BalanceAmountScenario.TooLow:
+                if (takerFee.eq(0)) {
+                    throw new Error(`Cannot set zrxAssetBalanceOfTaker TooLow if takerFee is 0`);
+                }
+                const tooLowBalance = takerFee.minus(1);
+                await this.assetWrapper.setBalanceAsync(this.takerAddress, this.zrxAssetData, tooLowBalance);
+                break;
+
+            case BalanceAmountScenario.Exact:
+                const exactBalance = takerFee;
+                await this.assetWrapper.setBalanceAsync(this.takerAddress, this.zrxAssetData, exactBalance);
+                break;
+
+            default:
+                throw errorUtils.spawnSwitchErr('takerStateScenario.zrxFeeBalance', takerStateScenario.zrxFeeBalance);
+        }
+
+        switch (takerStateScenario.traderAssetAllowance) {
+            case AllowanceAmountScenario.Higher:
+                break; // Noop since this is already the default
+
+            case AllowanceAmountScenario.TooLow:
+                const tooLowAllowance = takerAssetFillAmount.minus(1);
+                await this.assetWrapper.setProxyAllowanceAsync(
+                    this.takerAddress,
+                    signedOrder.takerAssetData,
+                    tooLowAllowance,
+                );
+                break;
+
+            case AllowanceAmountScenario.Exact:
+                const exactAllowance = takerAssetFillAmount;
+                await this.assetWrapper.setProxyAllowanceAsync(
+                    this.takerAddress,
+                    signedOrder.takerAssetData,
+                    exactAllowance,
+                );
+                break;
+
+            case AllowanceAmountScenario.Unlimited:
+                await this.assetWrapper.setProxyAllowanceAsync(
+                    this.takerAddress,
+                    signedOrder.takerAssetData,
+                    constants.UNLIMITED_ALLOWANCE_IN_BASE_UNITS,
+                );
+                break;
+
+            default:
+                throw errorUtils.spawnSwitchErr(
+                    'takerStateScenario.traderAssetAllowance',
+                    takerStateScenario.traderAssetAllowance,
+                );
+        }
+
+        switch (takerStateScenario.zrxFeeAllowance) {
+            case AllowanceAmountScenario.Higher:
+                break; // Noop since this is already the default
+
+            case AllowanceAmountScenario.TooLow:
+                const tooLowAllowance = takerFee.minus(1);
+                await this.assetWrapper.setProxyAllowanceAsync(
+                    signedOrder.takerAddress,
+                    this.zrxAssetData,
+                    tooLowAllowance,
+                );
+                break;
+
+            case AllowanceAmountScenario.Exact:
+                const exactAllowance = takerFee;
+                await this.assetWrapper.setProxyAllowanceAsync(
+                    signedOrder.takerAddress,
+                    this.zrxAssetData,
+                    exactAllowance,
+                );
+                break;
+
+            case AllowanceAmountScenario.Unlimited:
+                await this.assetWrapper.setProxyAllowanceAsync(
+                    signedOrder.takerAddress,
+                    this.zrxAssetData,
+                    constants.UNLIMITED_ALLOWANCE_IN_BASE_UNITS,
+                );
+                break;
+
+            default:
+                throw errorUtils.spawnSwitchErr(
+                    'takerStateScenario.zrxFeeAllowance',
+                    takerStateScenario.zrxFeeAllowance,
+                );
+        }
+    }
+} // tslint:disable:max-file-line-count
diff --git a/packages/contracts/src/utils/coverage.ts b/packages/contracts/test/utils/coverage.ts
index de29a3ecc..de29a3ecc 100644
--- a/packages/contracts/src/utils/coverage.ts
+++ b/packages/contracts/test/utils/coverage.ts
diff --git a/packages/contracts/src/utils/erc20_wrapper.ts b/packages/contracts/test/utils/erc20_wrapper.ts
index 91c9d50b7..53e9791bc 100644
--- a/packages/contracts/src/utils/erc20_wrapper.ts
+++ b/packages/contracts/test/utils/erc20_wrapper.ts
@@ -1,10 +1,11 @@
+import { assetProxyUtils } from '@0xproject/order-utils';
 import { BigNumber } from '@0xproject/utils';
 import { Web3Wrapper } from '@0xproject/web3-wrapper';
 import { Provider } from 'ethereum-types';
 import * as _ from 'lodash';
 
-import { DummyERC20TokenContract } from '../generated_contract_wrappers/dummy_e_r_c20_token';
-import { ERC20ProxyContract } from '../generated_contract_wrappers/e_r_c20_proxy';
+import { DummyERC20TokenContract } from '../../generated_contract_wrappers/dummy_e_r_c20_token';
+import { ERC20ProxyContract } from '../../generated_contract_wrappers/e_r_c20_proxy';
 
 import { artifacts } from './artifacts';
 import { constants } from './constants';
@@ -18,6 +19,7 @@ export class ERC20Wrapper {
     private _provider: Provider;
     private _dummyTokenContracts: DummyERC20TokenContract[];
     private _proxyContract?: ERC20ProxyContract;
+    private _proxyIdIfExists?: string;
     constructor(provider: Provider, tokenOwnerAddresses: string[], contractOwnerAddress: string) {
         this._dummyTokenContracts = [];
         this._web3Wrapper = new Web3Wrapper(provider);
@@ -25,8 +27,11 @@ export class ERC20Wrapper {
         this._tokenOwnerAddresses = tokenOwnerAddresses;
         this._contractOwnerAddress = contractOwnerAddress;
     }
-    public async deployDummyTokensAsync(): Promise<DummyERC20TokenContract[]> {
-        for (let i = 0; i < constants.NUM_DUMMY_ERC20_TO_DEPLOY; i++) {
+    public async deployDummyTokensAsync(
+        numberToDeploy: number,
+        decimals: BigNumber,
+    ): Promise<DummyERC20TokenContract[]> {
+        for (let i = 0; i < numberToDeploy; i++) {
             this._dummyTokenContracts.push(
                 await DummyERC20TokenContract.deployFrom0xArtifactAsync(
                     artifacts.DummyERC20Token,
@@ -34,7 +39,7 @@ export class ERC20Wrapper {
                     txDefaults,
                     constants.DUMMY_TOKEN_NAME,
                     constants.DUMMY_TOKEN_SYMBOL,
-                    constants.DUMMY_TOKEN_DECIMALS,
+                    decimals,
                     constants.DUMMY_TOKEN_TOTAL_SUPPLY,
                 ),
             );
@@ -47,8 +52,13 @@ export class ERC20Wrapper {
             this._provider,
             txDefaults,
         );
+        this._proxyIdIfExists = await this._proxyContract.getProxyId.callAsync();
         return this._proxyContract;
     }
+    public getProxyId(): string {
+        this._validateProxyContractExistsOrThrow();
+        return this._proxyIdIfExists as string;
+    }
     public async setBalancesAndAllowancesAsync(): Promise<void> {
         this._validateDummyTokenContractsExistOrThrow();
         this._validateProxyContractExistsOrThrow();
@@ -73,6 +83,36 @@ export class ERC20Wrapper {
             }
         }
     }
+    public async getBalanceAsync(userAddress: string, assetData: string): Promise<BigNumber> {
+        const tokenContract = this._getTokenContractFromAssetData(assetData);
+        const balance = new BigNumber(await tokenContract.balanceOf.callAsync(userAddress));
+        return balance;
+    }
+    public async setBalanceAsync(userAddress: string, assetData: string, amount: BigNumber): Promise<void> {
+        const tokenContract = this._getTokenContractFromAssetData(assetData);
+        await this._web3Wrapper.awaitTransactionSuccessAsync(
+            await tokenContract.setBalance.sendTransactionAsync(userAddress, amount, {
+                from: this._contractOwnerAddress,
+            }),
+            constants.AWAIT_TRANSACTION_MINED_MS,
+        );
+    }
+    public async getProxyAllowanceAsync(userAddress: string, assetData: string): Promise<BigNumber> {
+        const tokenContract = this._getTokenContractFromAssetData(assetData);
+        const proxyAddress = (this._proxyContract as ERC20ProxyContract).address;
+        const allowance = new BigNumber(await tokenContract.allowance.callAsync(userAddress, proxyAddress));
+        return allowance;
+    }
+    public async setAllowanceAsync(userAddress: string, assetData: string, amount: BigNumber): Promise<void> {
+        const tokenContract = this._getTokenContractFromAssetData(assetData);
+        const proxyAddress = (this._proxyContract as ERC20ProxyContract).address;
+        await this._web3Wrapper.awaitTransactionSuccessAsync(
+            await tokenContract.approve.sendTransactionAsync(proxyAddress, amount, {
+                from: userAddress,
+            }),
+            constants.AWAIT_TRANSACTION_MINED_MS,
+        );
+    }
     public async getBalancesAsync(): Promise<ERC20BalancesByOwner> {
         this._validateDummyTokenContractsExistOrThrow();
         const balancesByOwner: ERC20BalancesByOwner = {};
@@ -105,6 +145,15 @@ export class ERC20Wrapper {
         const tokenAddresses = _.map(this._dummyTokenContracts, dummyTokenContract => dummyTokenContract.address);
         return tokenAddresses;
     }
+    private _getTokenContractFromAssetData(assetData: string): DummyERC20TokenContract {
+        const erc20ProxyData = assetProxyUtils.decodeERC20AssetData(assetData);
+        const tokenAddress = erc20ProxyData.tokenAddress;
+        const tokenContractIfExists = _.find(this._dummyTokenContracts, c => c.address === tokenAddress);
+        if (_.isUndefined(tokenContractIfExists)) {
+            throw new Error(`Token: ${tokenAddress} was not deployed through ERC20Wrapper`);
+        }
+        return tokenContractIfExists;
+    }
     private _validateDummyTokenContractsExistOrThrow(): void {
         if (_.isUndefined(this._dummyTokenContracts)) {
             throw new Error('Dummy ERC20 tokens not yet deployed, please call "deployDummyTokensAsync"');
diff --git a/packages/contracts/src/utils/erc721_wrapper.ts b/packages/contracts/test/utils/erc721_wrapper.ts
index b20d9acd2..6347f56e7 100644
--- a/packages/contracts/src/utils/erc721_wrapper.ts
+++ b/packages/contracts/test/utils/erc721_wrapper.ts
@@ -4,8 +4,8 @@ import { Web3Wrapper } from '@0xproject/web3-wrapper';
 import { Provider } from 'ethereum-types';
 import * as _ from 'lodash';
 
-import { DummyERC721TokenContract } from '../generated_contract_wrappers/dummy_e_r_c721_token';
-import { ERC721ProxyContract } from '../generated_contract_wrappers/e_r_c721_proxy';
+import { DummyERC721TokenContract } from '../../generated_contract_wrappers/dummy_e_r_c721_token';
+import { ERC721ProxyContract } from '../../generated_contract_wrappers/e_r_c721_proxy';
 
 import { artifacts } from './artifacts';
 import { constants } from './constants';
@@ -19,6 +19,7 @@ export class ERC721Wrapper {
     private _provider: Provider;
     private _dummyTokenContracts: DummyERC721TokenContract[];
     private _proxyContract?: ERC721ProxyContract;
+    private _proxyIdIfExists?: string;
     private _initialTokenIdsByOwner: ERC721TokenIdsByOwner = {};
     constructor(provider: Provider, tokenOwnerAddresses: string[], contractOwnerAddress: string) {
         this._web3Wrapper = new Web3Wrapper(provider);
@@ -47,8 +48,13 @@ export class ERC721Wrapper {
             this._provider,
             txDefaults,
         );
+        this._proxyIdIfExists = await this._proxyContract.getProxyId.callAsync();
         return this._proxyContract;
     }
+    public getProxyId(): string {
+        this._validateProxyContractExistsOrThrow();
+        return this._proxyIdIfExists as string;
+    }
     public async setBalancesAndAllowancesAsync(): Promise<void> {
         this._validateDummyTokenContractsExistOrThrow();
         this._validateProxyContractExistsOrThrow();
@@ -57,12 +63,7 @@ export class ERC721Wrapper {
             for (const tokenOwnerAddress of this._tokenOwnerAddresses) {
                 for (let i = 0; i < constants.NUM_ERC721_TOKENS_TO_MINT; i++) {
                     const tokenId = generatePseudoRandomSalt();
-                    await this._web3Wrapper.awaitTransactionSuccessAsync(
-                        await dummyTokenContract.mint.sendTransactionAsync(tokenOwnerAddress, tokenId, {
-                            from: this._contractOwnerAddress,
-                        }),
-                        constants.AWAIT_TRANSACTION_MINED_MS,
-                    );
+                    await this.mintAsync(dummyTokenContract.address, tokenId, tokenOwnerAddress);
                     if (_.isUndefined(this._initialTokenIdsByOwner[tokenOwnerAddress])) {
                         this._initialTokenIdsByOwner[tokenOwnerAddress] = {
                             [dummyTokenContract.address]: [],
@@ -72,19 +73,100 @@ export class ERC721Wrapper {
                         this._initialTokenIdsByOwner[tokenOwnerAddress][dummyTokenContract.address] = [];
                     }
                     this._initialTokenIdsByOwner[tokenOwnerAddress][dummyTokenContract.address].push(tokenId);
+
+                    await this.approveProxyAsync(dummyTokenContract.address, tokenId);
                 }
-                const shouldApprove = true;
-                await this._web3Wrapper.awaitTransactionSuccessAsync(
-                    await dummyTokenContract.setApprovalForAll.sendTransactionAsync(
-                        (this._proxyContract as ERC721ProxyContract).address,
-                        shouldApprove,
-                        { from: tokenOwnerAddress },
-                    ),
-                    constants.AWAIT_TRANSACTION_MINED_MS,
-                );
             }
         }
     }
+    public async doesTokenExistAsync(tokenAddress: string, tokenId: BigNumber): Promise<boolean> {
+        const tokenContract = this._getTokenContractFromAssetData(tokenAddress);
+        const doesExist = await tokenContract.exists.callAsync(tokenId);
+        return doesExist;
+    }
+    public async approveProxyAsync(tokenAddress: string, tokenId: BigNumber): Promise<void> {
+        const proxyAddress = (this._proxyContract as ERC721ProxyContract).address;
+        await this.approveAsync(proxyAddress, tokenAddress, tokenId);
+    }
+    public async approveProxyForAllAsync(tokenAddress: string, tokenId: BigNumber, isApproved: boolean): Promise<void> {
+        const tokenContract = this._getTokenContractFromAssetData(tokenAddress);
+        const tokenOwner = await this.ownerOfAsync(tokenAddress, tokenId);
+        const proxyAddress = (this._proxyContract as ERC721ProxyContract).address;
+        await this._web3Wrapper.awaitTransactionSuccessAsync(
+            await tokenContract.setApprovalForAll.sendTransactionAsync(proxyAddress, isApproved, {
+                from: tokenOwner,
+            }),
+            constants.AWAIT_TRANSACTION_MINED_MS,
+        );
+    }
+    public async approveAsync(to: string, tokenAddress: string, tokenId: BigNumber): Promise<void> {
+        const tokenContract = this._getTokenContractFromAssetData(tokenAddress);
+        const tokenOwner = await this.ownerOfAsync(tokenAddress, tokenId);
+        await this._web3Wrapper.awaitTransactionSuccessAsync(
+            await tokenContract.approve.sendTransactionAsync(to, tokenId, {
+                from: tokenOwner,
+            }),
+            constants.AWAIT_TRANSACTION_MINED_MS,
+        );
+    }
+    public async transferFromAsync(
+        tokenAddress: string,
+        tokenId: BigNumber,
+        currentOwner: string,
+        userAddress: string,
+    ): Promise<void> {
+        const tokenContract = this._getTokenContractFromAssetData(tokenAddress);
+        await this._web3Wrapper.awaitTransactionSuccessAsync(
+            await tokenContract.transferFrom.sendTransactionAsync(currentOwner, userAddress, tokenId, {
+                from: currentOwner,
+            }),
+            constants.AWAIT_TRANSACTION_MINED_MS,
+        );
+    }
+    public async mintAsync(tokenAddress: string, tokenId: BigNumber, userAddress: string): Promise<void> {
+        const tokenContract = this._getTokenContractFromAssetData(tokenAddress);
+        await this._web3Wrapper.awaitTransactionSuccessAsync(
+            await tokenContract.mint.sendTransactionAsync(userAddress, tokenId, {
+                from: this._contractOwnerAddress,
+            }),
+            constants.AWAIT_TRANSACTION_MINED_MS,
+        );
+    }
+    public async burnAsync(tokenAddress: string, tokenId: BigNumber, owner: string): Promise<void> {
+        const tokenContract = this._getTokenContractFromAssetData(tokenAddress);
+        await this._web3Wrapper.awaitTransactionSuccessAsync(
+            await tokenContract.burn.sendTransactionAsync(owner, tokenId, {
+                from: this._contractOwnerAddress,
+            }),
+            constants.AWAIT_TRANSACTION_MINED_MS,
+        );
+    }
+    public async ownerOfAsync(tokenAddress: string, tokenId: BigNumber): Promise<string> {
+        const tokenContract = this._getTokenContractFromAssetData(tokenAddress);
+        const owner = await tokenContract.ownerOf.callAsync(tokenId);
+        return owner;
+    }
+    public async isOwnerAsync(userAddress: string, tokenAddress: string, tokenId: BigNumber): Promise<boolean> {
+        const tokenContract = this._getTokenContractFromAssetData(tokenAddress);
+        const tokenOwner = await tokenContract.ownerOf.callAsync(tokenId);
+        const isOwner = tokenOwner === userAddress;
+        return isOwner;
+    }
+    public async isProxyApprovedForAllAsync(userAddress: string, tokenAddress: string): Promise<boolean> {
+        this._validateProxyContractExistsOrThrow();
+        const tokenContract = this._getTokenContractFromAssetData(tokenAddress);
+        const operator = (this._proxyContract as ERC721ProxyContract).address;
+        const didApproveAll = await tokenContract.isApprovedForAll.callAsync(userAddress, operator);
+        return didApproveAll;
+    }
+    public async isProxyApprovedAsync(tokenAddress: string, tokenId: BigNumber): Promise<boolean> {
+        this._validateProxyContractExistsOrThrow();
+        const tokenContract = this._getTokenContractFromAssetData(tokenAddress);
+        const approvedAddress = await tokenContract.getApproved.callAsync(tokenId);
+        const proxyAddress = (this._proxyContract as ERC721ProxyContract).address;
+        const isProxyAnApprovedOperator = approvedAddress === proxyAddress;
+        return isProxyAnApprovedOperator;
+    }
     public async getBalancesAsync(): Promise<ERC721TokenIdsByOwner> {
         this._validateDummyTokenContractsExistOrThrow();
         this._validateBalancesAndAllowancesSetOrThrow();
@@ -127,6 +209,13 @@ export class ERC721Wrapper {
         const tokenAddresses = _.map(this._dummyTokenContracts, dummyTokenContract => dummyTokenContract.address);
         return tokenAddresses;
     }
+    private _getTokenContractFromAssetData(tokenAddress: string): DummyERC721TokenContract {
+        const tokenContractIfExists = _.find(this._dummyTokenContracts, c => c.address === tokenAddress);
+        if (_.isUndefined(tokenContractIfExists)) {
+            throw new Error(`Token: ${tokenAddress} was not deployed through ERC20Wrapper`);
+        }
+        return tokenContractIfExists;
+    }
     private _validateDummyTokenContractsExistOrThrow(): void {
         if (_.isUndefined(this._dummyTokenContracts)) {
             throw new Error('Dummy ERC721 tokens not yet deployed, please call "deployDummyTokensAsync"');
diff --git a/packages/contracts/src/utils/exchange_wrapper.ts b/packages/contracts/test/utils/exchange_wrapper.ts
index 06eb70644..155d0eeb0 100644
--- a/packages/contracts/src/utils/exchange_wrapper.ts
+++ b/packages/contracts/test/utils/exchange_wrapper.ts
@@ -1,12 +1,10 @@
-import { AssetProxyId, SignedOrder } from '@0xproject/types';
+import { SignedOrder } from '@0xproject/types';
 import { BigNumber } from '@0xproject/utils';
 import { Web3Wrapper } from '@0xproject/web3-wrapper';
 import { Provider, TransactionReceiptWithDecodedLogs } from 'ethereum-types';
-import * as _ from 'lodash';
 
-import { ExchangeContract } from '../generated_contract_wrappers/exchange';
+import { ExchangeContract } from '../../generated_contract_wrappers/exchange';
 
-import { constants } from './constants';
 import { formatters } from './formatters';
 import { LogDecoder } from './log_decoder';
 import { orderUtils } from './order_utils';
@@ -33,8 +31,8 @@ export class ExchangeWrapper {
             params.signature,
             { from },
         );
-        const tx = await this._logDecoder.getTxWithDecodedLogsAsync(txHash);
-        return tx;
+        const txReceipt = await this._logDecoder.getTxWithDecodedLogsAsync(txHash);
+        return txReceipt;
     }
     public async cancelOrderAsync(signedOrder: SignedOrder, from: string): Promise<TransactionReceiptWithDecodedLogs> {
         const params = orderUtils.createCancel(signedOrder);
@@ -192,20 +190,10 @@ export class ExchangeWrapper {
         return tx;
     }
     public async registerAssetProxyAsync(
-        assetProxyId: AssetProxyId,
         assetProxyAddress: string,
         from: string,
-        opts: { oldAssetProxyAddressIfExists?: string } = {},
     ): Promise<TransactionReceiptWithDecodedLogs> {
-        const oldAssetProxyAddress = _.isUndefined(opts.oldAssetProxyAddressIfExists)
-            ? constants.NULL_ADDRESS
-            : opts.oldAssetProxyAddressIfExists;
-        const txHash = await this._exchange.registerAssetProxy.sendTransactionAsync(
-            assetProxyId,
-            assetProxyAddress,
-            oldAssetProxyAddress,
-            { from },
-        );
+        const txHash = await this._exchange.registerAssetProxy.sendTransactionAsync(assetProxyAddress, { from });
         const tx = await this._logDecoder.getTxWithDecodedLogsAsync(txHash);
         return tx;
     }
@@ -227,6 +215,10 @@ export class ExchangeWrapper {
         const filledAmount = new BigNumber(await this._exchange.filled.callAsync(orderHashHex));
         return filledAmount;
     }
+    public async isCancelledAsync(orderHashHex: string): Promise<boolean> {
+        const isCancelled = await this._exchange.cancelled.callAsync(orderHashHex);
+        return isCancelled;
+    }
     public async getOrderInfoAsync(signedOrder: SignedOrder): Promise<OrderInfo> {
         const orderInfo = (await this._exchange.getOrderInfo.callAsync(signedOrder)) as OrderInfo;
         return orderInfo;
diff --git a/packages/contracts/src/utils/formatters.ts b/packages/contracts/test/utils/formatters.ts
index 32e4787d6..32e4787d6 100644
--- a/packages/contracts/src/utils/formatters.ts
+++ b/packages/contracts/test/utils/formatters.ts
diff --git a/packages/contracts/src/utils/increase_time.ts b/packages/contracts/test/utils/increase_time.ts
index 4565d8dbc..4565d8dbc 100644
--- a/packages/contracts/src/utils/increase_time.ts
+++ b/packages/contracts/test/utils/increase_time.ts
diff --git a/packages/contracts/src/utils/log_decoder.ts b/packages/contracts/test/utils/log_decoder.ts
index 07127ba79..07127ba79 100644
--- a/packages/contracts/src/utils/log_decoder.ts
+++ b/packages/contracts/test/utils/log_decoder.ts
diff --git a/packages/contracts/src/utils/match_order_tester.ts b/packages/contracts/test/utils/match_order_tester.ts
index fbb1b99db..6145779b0 100644
--- a/packages/contracts/src/utils/match_order_tester.ts
+++ b/packages/contracts/test/utils/match_order_tester.ts
@@ -4,15 +4,11 @@ import { BigNumber } from '@0xproject/utils';
 import * as chai from 'chai';
 import * as _ from 'lodash';
 
-import { chaiSetup } from '../utils/chai_setup';
-import { ERC20Wrapper } from '../utils/erc20_wrapper';
-import { ERC721Wrapper } from '../utils/erc721_wrapper';
-import { ExchangeWrapper } from '../utils/exchange_wrapper';
-import {
-    ERC20BalancesByOwner,
-    ERC721TokenIdsByOwner,
-    TransferAmountsByMatchOrders as TransferAmounts,
-} from '../utils/types';
+import { chaiSetup } from './chai_setup';
+import { ERC20Wrapper } from './erc20_wrapper';
+import { ERC721Wrapper } from './erc721_wrapper';
+import { ExchangeWrapper } from './exchange_wrapper';
+import { ERC20BalancesByOwner, ERC721TokenIdsByOwner, TransferAmountsByMatchOrders as TransferAmounts } from './types';
 
 chaiSetup.configure();
 const expect = chai.expect;
diff --git a/packages/contracts/src/utils/multi_sig_wrapper.ts b/packages/contracts/test/utils/multi_sig_wrapper.ts
index b0d4fa8ab..6e7746dfc 100644
--- a/packages/contracts/src/utils/multi_sig_wrapper.ts
+++ b/packages/contracts/test/utils/multi_sig_wrapper.ts
@@ -3,8 +3,8 @@ import { Web3Wrapper } from '@0xproject/web3-wrapper';
 import { Provider, TransactionReceiptWithDecodedLogs } from 'ethereum-types';
 import * as _ from 'lodash';
 
-import { AssetProxyOwnerContract } from '../generated_contract_wrappers/asset_proxy_owner';
-import { MultiSigWalletContract } from '../generated_contract_wrappers/multi_sig_wallet';
+import { AssetProxyOwnerContract } from '../../generated_contract_wrappers/asset_proxy_owner';
+import { MultiSigWalletContract } from '../../generated_contract_wrappers/multi_sig_wallet';
 
 import { LogDecoder } from './log_decoder';
 
diff --git a/packages/contracts/src/utils/order_factory.ts b/packages/contracts/test/utils/order_factory.ts
index 009dbc396..009dbc396 100644
--- a/packages/contracts/src/utils/order_factory.ts
+++ b/packages/contracts/test/utils/order_factory.ts
diff --git a/packages/contracts/test/utils/order_factory_from_scenario.ts b/packages/contracts/test/utils/order_factory_from_scenario.ts
new file mode 100644
index 000000000..9670c1a59
--- /dev/null
+++ b/packages/contracts/test/utils/order_factory_from_scenario.ts
@@ -0,0 +1,277 @@
+import { assetProxyUtils, generatePseudoRandomSalt } from '@0xproject/order-utils';
+import { Order } from '@0xproject/types';
+import { BigNumber, errorUtils } from '@0xproject/utils';
+
+import { DummyERC721TokenContract } from '../../generated_contract_wrappers/dummy_e_r_c721_token';
+
+import { constants } from './constants';
+import {
+    AssetDataScenario,
+    ERC721TokenIdsByOwner,
+    ExpirationTimeSecondsScenario,
+    FeeRecipientAddressScenario,
+    OrderAssetAmountScenario,
+    OrderScenario,
+    TakerScenario,
+} from './types';
+
+const TEN_UNITS_EIGHTEEN_DECIMALS = new BigNumber(10_000_000_000_000_000_000);
+const FIVE_UNITS_EIGHTEEN_DECIMALS = new BigNumber(5_000_000_000_000_000_000);
+const POINT_ONE_UNITS_EIGHTEEN_DECIMALS = new BigNumber(100_000_000_000_000_000);
+const POINT_ZERO_FIVE_UNITS_EIGHTEEN_DECIMALS = new BigNumber(50_000_000_000_000_000);
+const TEN_UNITS_FIVE_DECIMALS = new BigNumber(1_000_000);
+const FIVE_UNITS_FIVE_DECIMALS = new BigNumber(500_000);
+const ONE_NFT_UNIT = new BigNumber(1);
+
+export class OrderFactoryFromScenario {
+    private _userAddresses: string[];
+    private _zrxAddress: string;
+    private _nonZrxERC20EighteenDecimalTokenAddresses: string[];
+    private _erc20FiveDecimalTokenAddresses: string[];
+    private _erc721Token: DummyERC721TokenContract;
+    private _erc721Balances: ERC721TokenIdsByOwner;
+    private _exchangeAddress: string;
+    constructor(
+        userAddresses: string[],
+        zrxAddress: string,
+        nonZrxERC20EighteenDecimalTokenAddresses: string[],
+        erc20FiveDecimalTokenAddresses: string[],
+        erc721Token: DummyERC721TokenContract,
+        erc721Balances: ERC721TokenIdsByOwner,
+        exchangeAddress: string,
+    ) {
+        this._userAddresses = userAddresses;
+        this._zrxAddress = zrxAddress;
+        this._nonZrxERC20EighteenDecimalTokenAddresses = nonZrxERC20EighteenDecimalTokenAddresses;
+        this._erc20FiveDecimalTokenAddresses = erc20FiveDecimalTokenAddresses;
+        this._erc721Token = erc721Token;
+        this._erc721Balances = erc721Balances;
+        this._exchangeAddress = exchangeAddress;
+    }
+    public generateOrder(orderScenario: OrderScenario): Order {
+        const makerAddress = this._userAddresses[1];
+        let takerAddress = this._userAddresses[2];
+        const erc721MakerAssetIds = this._erc721Balances[makerAddress][this._erc721Token.address];
+        const erc721TakerAssetIds = this._erc721Balances[takerAddress][this._erc721Token.address];
+        let feeRecipientAddress;
+        let makerAssetAmount;
+        let takerAssetAmount;
+        let makerFee;
+        let takerFee;
+        let expirationTimeSeconds;
+        let makerAssetData;
+        let takerAssetData;
+
+        switch (orderScenario.feeRecipientScenario) {
+            case FeeRecipientAddressScenario.BurnAddress:
+                feeRecipientAddress = constants.NULL_ADDRESS;
+                break;
+            case FeeRecipientAddressScenario.EthUserAddress:
+                feeRecipientAddress = this._userAddresses[4];
+                break;
+            default:
+                throw errorUtils.spawnSwitchErr('FeeRecipientAddressScenario', orderScenario.feeRecipientScenario);
+        }
+
+        switch (orderScenario.makerAssetDataScenario) {
+            case AssetDataScenario.ZRXFeeToken:
+                makerAssetData = assetProxyUtils.encodeERC20AssetData(this._zrxAddress);
+                break;
+            case AssetDataScenario.ERC20NonZRXEighteenDecimals:
+                makerAssetData = assetProxyUtils.encodeERC20AssetData(
+                    this._nonZrxERC20EighteenDecimalTokenAddresses[0],
+                );
+                break;
+            case AssetDataScenario.ERC20FiveDecimals:
+                makerAssetData = assetProxyUtils.encodeERC20AssetData(this._erc20FiveDecimalTokenAddresses[0]);
+                break;
+            case AssetDataScenario.ERC721:
+                makerAssetData = assetProxyUtils.encodeERC721AssetData(
+                    this._erc721Token.address,
+                    erc721MakerAssetIds[0],
+                );
+                break;
+            default:
+                throw errorUtils.spawnSwitchErr('AssetDataScenario', orderScenario.makerAssetDataScenario);
+        }
+
+        switch (orderScenario.takerAssetDataScenario) {
+            case AssetDataScenario.ZRXFeeToken:
+                takerAssetData = assetProxyUtils.encodeERC20AssetData(this._zrxAddress);
+                break;
+            case AssetDataScenario.ERC20NonZRXEighteenDecimals:
+                takerAssetData = assetProxyUtils.encodeERC20AssetData(
+                    this._nonZrxERC20EighteenDecimalTokenAddresses[1],
+                );
+                break;
+            case AssetDataScenario.ERC20FiveDecimals:
+                takerAssetData = assetProxyUtils.encodeERC20AssetData(this._erc20FiveDecimalTokenAddresses[1]);
+                break;
+            case AssetDataScenario.ERC721:
+                takerAssetData = assetProxyUtils.encodeERC721AssetData(
+                    this._erc721Token.address,
+                    erc721TakerAssetIds[0],
+                );
+                break;
+            default:
+                throw errorUtils.spawnSwitchErr('AssetDataScenario', orderScenario.takerAssetDataScenario);
+        }
+
+        switch (orderScenario.makerAssetAmountScenario) {
+            case OrderAssetAmountScenario.Large:
+                switch (orderScenario.makerAssetDataScenario) {
+                    case AssetDataScenario.ZRXFeeToken:
+                    case AssetDataScenario.ERC20NonZRXEighteenDecimals:
+                        makerAssetAmount = TEN_UNITS_EIGHTEEN_DECIMALS;
+                        break;
+                    case AssetDataScenario.ERC20FiveDecimals:
+                        makerAssetAmount = TEN_UNITS_FIVE_DECIMALS;
+                        break;
+                    case AssetDataScenario.ERC721:
+                        makerAssetAmount = ONE_NFT_UNIT;
+                        break;
+                    default:
+                        throw errorUtils.spawnSwitchErr('AssetDataScenario', orderScenario.makerAssetDataScenario);
+                }
+                break;
+            case OrderAssetAmountScenario.Small:
+                switch (orderScenario.makerAssetDataScenario) {
+                    case AssetDataScenario.ZRXFeeToken:
+                    case AssetDataScenario.ERC20NonZRXEighteenDecimals:
+                        makerAssetAmount = FIVE_UNITS_EIGHTEEN_DECIMALS;
+                        break;
+                    case AssetDataScenario.ERC20FiveDecimals:
+                        makerAssetAmount = FIVE_UNITS_FIVE_DECIMALS;
+                        break;
+                    case AssetDataScenario.ERC721:
+                        makerAssetAmount = ONE_NFT_UNIT;
+                        break;
+                    default:
+                        throw errorUtils.spawnSwitchErr('AssetDataScenario', orderScenario.makerAssetDataScenario);
+                }
+                break;
+            case OrderAssetAmountScenario.Zero:
+                makerAssetAmount = new BigNumber(0);
+                break;
+            default:
+                throw errorUtils.spawnSwitchErr('OrderAssetAmountScenario', orderScenario.makerAssetAmountScenario);
+        }
+
+        switch (orderScenario.takerAssetAmountScenario) {
+            case OrderAssetAmountScenario.Large:
+                switch (orderScenario.takerAssetDataScenario) {
+                    case AssetDataScenario.ERC20NonZRXEighteenDecimals:
+                    case AssetDataScenario.ZRXFeeToken:
+                        takerAssetAmount = TEN_UNITS_EIGHTEEN_DECIMALS;
+                        break;
+                    case AssetDataScenario.ERC20FiveDecimals:
+                        takerAssetAmount = TEN_UNITS_FIVE_DECIMALS;
+                        break;
+                    case AssetDataScenario.ERC721:
+                        takerAssetAmount = ONE_NFT_UNIT;
+                        break;
+                    default:
+                        throw errorUtils.spawnSwitchErr('AssetDataScenario', orderScenario.takerAssetDataScenario);
+                }
+                break;
+            case OrderAssetAmountScenario.Small:
+                switch (orderScenario.takerAssetDataScenario) {
+                    case AssetDataScenario.ERC20NonZRXEighteenDecimals:
+                    case AssetDataScenario.ZRXFeeToken:
+                        takerAssetAmount = FIVE_UNITS_EIGHTEEN_DECIMALS;
+                        break;
+                    case AssetDataScenario.ERC20FiveDecimals:
+                        takerAssetAmount = FIVE_UNITS_FIVE_DECIMALS;
+                        break;
+                    case AssetDataScenario.ERC721:
+                        takerAssetAmount = ONE_NFT_UNIT;
+                        break;
+                    default:
+                        throw errorUtils.spawnSwitchErr('AssetDataScenario', orderScenario.takerAssetDataScenario);
+                }
+                break;
+            case OrderAssetAmountScenario.Zero:
+                takerAssetAmount = new BigNumber(0);
+                break;
+            default:
+                throw errorUtils.spawnSwitchErr('OrderAssetAmountScenario', orderScenario.takerAssetAmountScenario);
+        }
+
+        switch (orderScenario.makerFeeScenario) {
+            case OrderAssetAmountScenario.Large:
+                makerFee = POINT_ONE_UNITS_EIGHTEEN_DECIMALS;
+                break;
+            case OrderAssetAmountScenario.Small:
+                makerFee = POINT_ZERO_FIVE_UNITS_EIGHTEEN_DECIMALS;
+                break;
+            case OrderAssetAmountScenario.Zero:
+                makerFee = new BigNumber(0);
+                break;
+            default:
+                throw errorUtils.spawnSwitchErr('OrderAssetAmountScenario', orderScenario.makerFeeScenario);
+        }
+
+        switch (orderScenario.takerFeeScenario) {
+            case OrderAssetAmountScenario.Large:
+                takerFee = POINT_ONE_UNITS_EIGHTEEN_DECIMALS;
+                break;
+            case OrderAssetAmountScenario.Small:
+                takerFee = POINT_ZERO_FIVE_UNITS_EIGHTEEN_DECIMALS;
+                break;
+            case OrderAssetAmountScenario.Zero:
+                takerFee = new BigNumber(0);
+                break;
+            default:
+                throw errorUtils.spawnSwitchErr('OrderAssetAmountScenario', orderScenario.takerFeeScenario);
+        }
+
+        switch (orderScenario.expirationTimeSecondsScenario) {
+            case ExpirationTimeSecondsScenario.InFuture:
+                expirationTimeSeconds = new BigNumber(2524604400); // Close to infinite
+                break;
+            case ExpirationTimeSecondsScenario.InPast:
+                expirationTimeSeconds = new BigNumber(0); // Jan 1, 1970
+                break;
+            default:
+                throw errorUtils.spawnSwitchErr(
+                    'ExpirationTimeSecondsScenario',
+                    orderScenario.expirationTimeSecondsScenario,
+                );
+        }
+
+        switch (orderScenario.takerScenario) {
+            case TakerScenario.CorrectlySpecified:
+                break; // noop since takerAddress is already specified
+
+            case TakerScenario.IncorrectlySpecified:
+                const notTaker = this._userAddresses[3];
+                takerAddress = notTaker;
+                break;
+
+            case TakerScenario.Unspecified:
+                takerAddress = constants.NULL_ADDRESS;
+                break;
+
+            default:
+                throw errorUtils.spawnSwitchErr('TakerScenario', orderScenario.takerScenario);
+        }
+
+        const order = {
+            senderAddress: constants.NULL_ADDRESS,
+            makerAddress,
+            takerAddress,
+            makerFee,
+            takerFee,
+            makerAssetAmount,
+            takerAssetAmount,
+            makerAssetData,
+            takerAssetData,
+            salt: generatePseudoRandomSalt(),
+            exchangeAddress: this._exchangeAddress,
+            feeRecipientAddress,
+            expirationTimeSeconds,
+        };
+
+        return order;
+    }
+}
diff --git a/packages/contracts/src/utils/order_utils.ts b/packages/contracts/test/utils/order_utils.ts
index a9f994d80..019f6e74b 100644
--- a/packages/contracts/src/utils/order_utils.ts
+++ b/packages/contracts/test/utils/order_utils.ts
@@ -5,6 +5,13 @@ import { constants } from './constants';
 import { CancelOrder, MatchOrder } from './types';
 
 export const orderUtils = {
+    getPartialAmount(numerator: BigNumber, denominator: BigNumber, target: BigNumber): BigNumber {
+        const partialAmount = numerator
+            .mul(target)
+            .div(denominator)
+            .floor();
+        return partialAmount;
+    },
     createFill: (signedOrder: SignedOrder, takerAssetFillAmount?: BigNumber) => {
         const fill = {
             order: orderUtils.getOrderWithoutExchangeAddress(signedOrder),
diff --git a/packages/contracts/src/utils/profiler.ts b/packages/contracts/test/utils/profiler.ts
index 85ee24f22..85ee24f22 100644
--- a/packages/contracts/src/utils/profiler.ts
+++ b/packages/contracts/test/utils/profiler.ts
diff --git a/packages/contracts/src/utils/revert_trace.ts b/packages/contracts/test/utils/revert_trace.ts
index 0bf8384bc..0bf8384bc 100644
--- a/packages/contracts/src/utils/revert_trace.ts
+++ b/packages/contracts/test/utils/revert_trace.ts
diff --git a/packages/contracts/src/utils/signing_utils.ts b/packages/contracts/test/utils/signing_utils.ts
index 9c711c72c..9c711c72c 100644
--- a/packages/contracts/src/utils/signing_utils.ts
+++ b/packages/contracts/test/utils/signing_utils.ts
diff --git a/packages/contracts/test/utils/simple_asset_balance_and_proxy_allowance_fetcher.ts b/packages/contracts/test/utils/simple_asset_balance_and_proxy_allowance_fetcher.ts
new file mode 100644
index 000000000..a295a40c4
--- /dev/null
+++ b/packages/contracts/test/utils/simple_asset_balance_and_proxy_allowance_fetcher.ts
@@ -0,0 +1,19 @@
+import { AbstractBalanceAndProxyAllowanceFetcher } from '@0xproject/order-utils';
+import { BigNumber } from '@0xproject/utils';
+
+import { AssetWrapper } from './asset_wrapper';
+
+export class SimpleAssetBalanceAndProxyAllowanceFetcher implements AbstractBalanceAndProxyAllowanceFetcher {
+    private _assetWrapper: AssetWrapper;
+    constructor(assetWrapper: AssetWrapper) {
+        this._assetWrapper = assetWrapper;
+    }
+    public async getBalanceAsync(assetData: string, userAddress: string): Promise<BigNumber> {
+        const balance = await this._assetWrapper.getBalanceAsync(userAddress, assetData);
+        return balance;
+    }
+    public async getProxyAllowanceAsync(assetData: string, userAddress: string): Promise<BigNumber> {
+        const proxyAllowance = await this._assetWrapper.getProxyAllowanceAsync(userAddress, assetData);
+        return proxyAllowance;
+    }
+}
diff --git a/packages/contracts/test/utils/simple_order_filled_cancelled_fetcher.ts b/packages/contracts/test/utils/simple_order_filled_cancelled_fetcher.ts
new file mode 100644
index 000000000..24afe36b7
--- /dev/null
+++ b/packages/contracts/test/utils/simple_order_filled_cancelled_fetcher.ts
@@ -0,0 +1,24 @@
+import { AbstractOrderFilledCancelledFetcher } from '@0xproject/order-utils';
+import { BigNumber } from '@0xproject/utils';
+
+import { ExchangeWrapper } from './exchange_wrapper';
+
+export class SimpleOrderFilledCancelledFetcher implements AbstractOrderFilledCancelledFetcher {
+    private _exchangeWrapper: ExchangeWrapper;
+    private _zrxAssetData: string;
+    constructor(exchange: ExchangeWrapper, zrxAssetData: string) {
+        this._exchangeWrapper = exchange;
+        this._zrxAssetData = zrxAssetData;
+    }
+    public async getFilledTakerAmountAsync(orderHash: string): Promise<BigNumber> {
+        const filledTakerAmount = new BigNumber(await this._exchangeWrapper.getTakerAssetFilledAmountAsync(orderHash));
+        return filledTakerAmount;
+    }
+    public async isOrderCancelledAsync(orderHash: string): Promise<boolean> {
+        const isCancelled = await this._exchangeWrapper.isCancelledAsync(orderHash);
+        return isCancelled;
+    }
+    public getZRXAssetData(): string {
+        return this._zrxAssetData;
+    }
+}
diff --git a/packages/contracts/src/utils/token_registry_wrapper.ts b/packages/contracts/test/utils/token_registry_wrapper.ts
index 91895aa59..0abf20e03 100644
--- a/packages/contracts/src/utils/token_registry_wrapper.ts
+++ b/packages/contracts/test/utils/token_registry_wrapper.ts
@@ -1,7 +1,7 @@
 import { Web3Wrapper } from '@0xproject/web3-wrapper';
 import { Provider } from 'ethereum-types';
 
-import { TokenRegistryContract } from '../generated_contract_wrappers/token_registry';
+import { TokenRegistryContract } from '../../generated_contract_wrappers/token_registry';
 
 import { Token } from './types';
 
diff --git a/packages/contracts/src/utils/transaction_factory.ts b/packages/contracts/test/utils/transaction_factory.ts
index 348c0715d..348c0715d 100644
--- a/packages/contracts/src/utils/transaction_factory.ts
+++ b/packages/contracts/test/utils/transaction_factory.ts
diff --git a/packages/contracts/src/utils/types.ts b/packages/contracts/test/utils/types.ts
index 5dfac64fc..b792bb90a 100644
--- a/packages/contracts/src/utils/types.ts
+++ b/packages/contracts/test/utils/types.ts
@@ -150,3 +150,80 @@ export interface MatchOrder {
     leftSignature: string;
     rightSignature: string;
 }
+
+// Combinatorial testing types
+
+export enum FeeRecipientAddressScenario {
+    BurnAddress = 'BURN_ADDRESS',
+    EthUserAddress = 'ETH_USER_ADDRESS',
+}
+
+export enum OrderAssetAmountScenario {
+    Zero = 'ZERO',
+    Large = 'LARGE',
+    Small = 'SMALL',
+}
+
+export enum TakerScenario {
+    CorrectlySpecified = 'CORRECTLY_SPECIFIED',
+    IncorrectlySpecified = 'INCORRECTLY_SPECIFIED',
+    Unspecified = 'UNSPECIFIED',
+}
+
+export enum ExpirationTimeSecondsScenario {
+    InPast = 'IN_PAST',
+    InFuture = 'IN_FUTURE',
+}
+
+export enum AssetDataScenario {
+    ERC721 = 'ERC721',
+    ZRXFeeToken = 'ZRX_FEE_TOKEN',
+    ERC20FiveDecimals = 'ERC20_FIVE_DECIMALS',
+    ERC20NonZRXEighteenDecimals = 'ERC20_NON_ZRX_EIGHTEEN_DECIMALS',
+}
+
+export enum TakerAssetFillAmountScenario {
+    Zero = 'ZERO',
+    GreaterThanRemainingFillableTakerAssetAmount = 'GREATER_THAN_REMAINING_FILLABLE_TAKER_ASSET_AMOUNT',
+    LessThanRemainingFillableTakerAssetAmount = 'LESS_THAN_REMAINING_FILLABLE_TAKER_ASSET_AMOUNT',
+    ExactlyRemainingFillableTakerAssetAmount = 'EXACTLY_REMAINING_FILLABLE_TAKER_ASSET_AMOUNT',
+}
+
+export interface OrderScenario {
+    takerScenario: TakerScenario;
+    feeRecipientScenario: FeeRecipientAddressScenario;
+    makerAssetAmountScenario: OrderAssetAmountScenario;
+    takerAssetAmountScenario: OrderAssetAmountScenario;
+    makerFeeScenario: OrderAssetAmountScenario;
+    takerFeeScenario: OrderAssetAmountScenario;
+    expirationTimeSecondsScenario: ExpirationTimeSecondsScenario;
+    makerAssetDataScenario: AssetDataScenario;
+    takerAssetDataScenario: AssetDataScenario;
+}
+
+export enum BalanceAmountScenario {
+    Exact = 'EXACT',
+    TooLow = 'TOO_LOW',
+    Higher = 'HIGHER',
+}
+
+export enum AllowanceAmountScenario {
+    Exact = 'EXACT',
+    TooLow = 'TOO_LOW',
+    Higher = 'HIGHER',
+    Unlimited = 'UNLIMITED',
+}
+
+export interface TraderStateScenario {
+    traderAssetBalance: BalanceAmountScenario;
+    traderAssetAllowance: AllowanceAmountScenario;
+    zrxFeeBalance: BalanceAmountScenario;
+    zrxFeeAllowance: AllowanceAmountScenario;
+}
+
+export interface FillScenario {
+    orderScenario: OrderScenario;
+    takerAssetFillAmountScenario: TakerAssetFillAmountScenario;
+    makerStateScenario: TraderStateScenario;
+    takerStateScenario: TraderStateScenario;
+}
diff --git a/packages/contracts/src/utils/web3_wrapper.ts b/packages/contracts/test/utils/web3_wrapper.ts
index c9d83a02d..c9d83a02d 100644
--- a/packages/contracts/src/utils/web3_wrapper.ts
+++ b/packages/contracts/test/utils/web3_wrapper.ts