Merge branch 'v2-prototype' into fix/five_decimal_scenario

* v2-prototype: (75 commits)
  Update relayer grid tiles to use Text
  Fix build
  Update file structure
  Update 2.0.0 artifacts
  Move ledgerhq module declarations to typescript-typings
  Export LedgerEthereumClient type in subproviders
  Update artifacts
  Add logging and updated artifacts
  Fix migrations
  Run prettier
  Add Kovan artifacts
  Use ledger subprovider
  Add Kovan migrations
  Remove state variable from Link component in Portal
  Make registerAssetProxy append only
  Update staging api link
  Change getTransactionReceipt to awaitTransactionMined
  Move /docs route to the end
  Remove extra call to scrollIntoView for wallet in onboarding
  Update expectRevertReasonOrAlwaysFailingTransactionAsync to check status codes
  ...

130 files changed, 874 insertions, 936 deletions

diff --git a/packages/contracts/compiler.json b/packages/contracts/compiler.json
index 1ee58081a..56c8b1761 100644
--- a/packages/contracts/compiler.json
+++ b/packages/contracts/compiler.json
@@ -29,6 +29,7 @@
         "Exchange",
         "ExchangeWrapper",
         "IAssetData",
+        "IAssetProxy",
         "IValidator",
         "IWallet",
         "MixinAuthorizable",
diff --git a/packages/contracts/package.json b/packages/contracts/package.json
index b5a599fe5..e0e82adc7 100644
--- a/packages/contracts/package.json
+++ b/packages/contracts/package.json
@@ -14,7 +14,7 @@
         "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",
@@ -22,10 +22,10 @@
         "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",
+        "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",
@@ -35,7 +35,7 @@
     },
     "config": {
         "abis":
-            "../migrations/artifacts/2.0.0/@(AssetProxyOwner|DummyERC20Token|DummyERC721Receiver|DummyERC721Token|ERC20Proxy|ERC721Proxy|Exchange|ExchangeWrapper|IAssetData|MixinAuthorizable|MultiSigWallet|MultiSigWalletWithTimeLock|TestAssetProxyOwner|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 3b9584a44..3b9584a44 100644
--- a/packages/contracts/src/contracts/current/protocol/AssetProxy/MixinAuthorizable.sol
+++ b/packages/contracts/src/2.0.0/protocol/AssetProxy/MixinAuthorizable.sol
diff --git a/packages/contracts/src/contracts/current/protocol/AssetProxy/interfaces/IAssetData.sol b/packages/contracts/src/2.0.0/protocol/AssetProxy/interfaces/IAssetData.sol
index 8c78ee8c4..7ebd6acf0 100644
--- a/packages/contracts/src/contracts/current/protocol/AssetProxy/interfaces/IAssetData.sol
+++ b/packages/contracts/src/2.0.0/protocol/AssetProxy/interfaces/IAssetData.sol
@@ -23,14 +23,16 @@ pragma solidity ^0.4.23;
 // This argument is ABI encoded as one of the methods of this interface.
 interface IAssetData {
     
-    function ERC20Token(
-        address tokenContract)
-        external pure;
+    function ERC20Token(address tokenContract)
+        external
+        pure;
     
     function ERC721Token(
         address tokenContract,
         uint256 tokenId,
-        bytes receiverData)
-        external pure;
+        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 ae8e195da..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
@@ -42,6 +42,6 @@ contract IAssetProxy is
     /// @return Proxy id.
     function getProxyId()
         external
-        view
+        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 338cb12e2..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
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/contracts/current/protocol/Exchange/MixinAssetProxyDispatcher.sol b/packages/contracts/src/2.0.0/protocol/Exchange/MixinAssetProxyDispatcher.sol
index f7086f543..9e9d88ce7 100644
--- a/packages/contracts/src/contracts/current/protocol/Exchange/MixinAssetProxyDispatcher.sol
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/MixinAssetProxyDispatcher.sol
@@ -32,43 +32,28 @@ contract MixinAssetProxyDispatcher is
     // Mapping from Asset Proxy Id's to their respective Asset Proxy
     mapping (bytes4 => 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(
-        bytes4 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
         onlyOwner
     {
-        // Ensure the existing asset proxy is not unintentionally overwritten
+        IAssetProxy assetProxyContract = IAssetProxy(assetProxy);
+
+        // Ensure that no asset proxy exists with current id.
+        bytes4 assetProxyId = assetProxyContract.getProxyId();
         address currentAssetProxy = assetProxies[assetProxyId];
         require(
-            oldAssetProxy == currentAssetProxy,
-            "ASSET_PROXY_MISMATCH"
+            currentAssetProxy == address(0),
+            "ASSET_PROXY_ALREADY_EXISTS"
         );
 
-        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)) {
-            bytes4 newAssetProxyId = assetProxy.getProxyId();
-            require(
-                newAssetProxyId == assetProxyId,
-                "ASSET_PROXY_ID_MISMATCH"
-            );
-        }
-
         // Add asset proxy and log registration.
-        assetProxies[assetProxyId] = assetProxy;
-        emit AssetProxySet(
+        assetProxies[assetProxyId] = assetProxyContract;
+        emit AssetProxyRegistered(
             assetProxyId,
-            newAssetProxy,
-            oldAssetProxy
+            assetProxy
         );
     }
 
@@ -112,7 +97,7 @@ contract MixinAssetProxyDispatcher is
                     0xFFFFFFFF00000000000000000000000000000000000000000000000000000000
                 )
             }
-            IAssetProxy assetProxy = assetProxies[assetProxyId];
+            address assetProxy = assetProxies[assetProxyId];
 
             // Ensure that assetProxy exists
             require(
@@ -135,7 +120,6 @@ contract MixinAssetProxyDispatcher is
             // |          | 132    | 32      | assetData Length                            |
             // |          | 164    | **      | assetData Contents                          |
 
-            bool success;
             assembly {
                 /////// Setup State ///////
                 // `cdStart` is the start of the calldata for `assetProxy.transferFrom` (equal to free memory ptr).
@@ -173,7 +157,7 @@ contract MixinAssetProxyDispatcher is
                 }
 
                 /////// Call `assetProxy.transferFrom` using the constructed calldata ///////
-                success := call(
+                let success := call(
                     gas,                    // forward all gas
                     assetProxy,             // call address of asset proxy
                     0,                      // don't send any ETH
@@ -182,7 +166,7 @@ contract MixinAssetProxyDispatcher is
                     cdStart,                // write output over input
                     512                     // reserve 512 bytes for output
                 )
-                if eq(success, 0) {
+                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 c0ed023ac..c0ed023ac 100644
--- a/packages/contracts/src/contracts/current/protocol/Exchange/MixinExchangeCore.sol
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/MixinExchangeCore.sol
diff --git a/packages/contracts/src/contracts/current/protocol/Exchange/MixinMatchOrders.sol b/packages/contracts/src/2.0.0/protocol/Exchange/MixinMatchOrders.sol
index 1a43eec79..1a43eec79 100644
--- a/packages/contracts/src/contracts/current/protocol/Exchange/MixinMatchOrders.sol
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/MixinMatchOrders.sol
diff --git a/packages/contracts/src/contracts/current/protocol/Exchange/MixinSignatureValidator.sol b/packages/contracts/src/2.0.0/protocol/Exchange/MixinSignatureValidator.sol
index 29172057a..29172057a 100644
--- a/packages/contracts/src/contracts/current/protocol/Exchange/MixinSignatureValidator.sol
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/MixinSignatureValidator.sol
diff --git a/packages/contracts/src/contracts/current/protocol/Exchange/MixinTransactions.sol b/packages/contracts/src/2.0.0/protocol/Exchange/MixinTransactions.sol
index e0f450d0a..31f7f2847 100644
--- a/packages/contracts/src/contracts/current/protocol/Exchange/MixinTransactions.sol
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/MixinTransactions.sol
@@ -60,6 +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)
diff --git a/packages/contracts/src/contracts/current/protocol/Exchange/MixinWrapperFunctions.sol b/packages/contracts/src/2.0.0/protocol/Exchange/MixinWrapperFunctions.sol
index 00668ca43..00668ca43 100644
--- a/packages/contracts/src/contracts/current/protocol/Exchange/MixinWrapperFunctions.sol
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/MixinWrapperFunctions.sol
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 fa55dff00..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
@@ -20,16 +20,10 @@ 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(
-        bytes4 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.
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 488ca956c..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
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 e37f41ada..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
@@ -54,8 +54,7 @@ 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.
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 bfe2fd33f..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
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 c2b506dcf..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
@@ -26,10 +26,9 @@ contract MAssetProxyDispatcher is
 {
 
     // Logs registration of new asset proxy
-    event AssetProxySet(
+    event AssetProxyRegistered(
         bytes4 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).
+        address assetProxy      // Address of new registered AssetProxy.
     );
 
     /// @dev Forwards arguments to assetProxy and calls `transferFrom`. Either succeeds or throws.
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 78ea96447..78ea96447 100644
--- a/packages/contracts/src/contracts/current/test/DummyERC721Token/DummyERC721Token.sol
+++ b/packages/contracts/src/2.0.0/test/DummyERC721Token/DummyERC721Token.sol
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 2ae69e0ef..2ae69e0ef 100644
--- a/packages/contracts/src/contracts/current/test/TestAssetProxyDispatcher/TestAssetProxyDispatcher.sol
+++ b/packages/contracts/src/2.0.0/test/TestAssetProxyDispatcher/TestAssetProxyDispatcher.sol
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 8b52858b1..8b52858b1 100644
--- a/packages/contracts/src/contracts/current/test/Whitelist/Whitelist.sol
+++ b/packages/contracts/src/2.0.0/test/Whitelist/Whitelist.sol
diff --git a/packages/contracts/src/contracts/current/tokens/ERC20Token/ERC20Token.sol b/packages/contracts/src/2.0.0/tokens/ERC20Token/ERC20Token.sol
index b6961a6ec..b6961a6ec 100644
--- a/packages/contracts/src/contracts/current/tokens/ERC20Token/ERC20Token.sol
+++ b/packages/contracts/src/2.0.0/tokens/ERC20Token/ERC20Token.sol
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 78b1ddf7c..78b1ddf7c 100644
--- a/packages/contracts/src/contracts/current/utils/LibBytes/LibBytes.sol
+++ b/packages/contracts/src/2.0.0/utils/LibBytes/LibBytes.sol
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 6f5761cc7..6f5761cc7 100644
--- a/packages/contracts/src/contracts/current/utils/Ownable/Ownable.sol
+++ b/packages/contracts/src/2.0.0/utils/Ownable/Ownable.sol
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 b4780b52b..000000000
--- a/packages/contracts/src/contracts/current/protocol/AssetProxy/ERC20Proxy.sol
+++ /dev/null
@@ -1,167 +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 "./interfaces/IAssetProxy.sol";
-import "./MixinAuthorizable.sol";
-
-contract ERC20Proxy is
-    IAssetProxy,
-    MixinAuthorizable
-{
-    // Id of this proxy.
-    bytes4 constant PROXY_ID = bytes4(keccak256("ERC20Token(address)"));
-    
-    /// @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 transferFrom(
-        bytes assetData,
-        address from,
-        address to,
-        uint256 amount
-    )
-        external
-    {
-        require(
-            authorized[msg.sender],
-            "SENDER_NOT_AUTHORIZED"
-        );
-
-        // `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   |        | 1 * 32  | function parameters:                |
-        // |          | 4      | 12 + 20 |   1. token address                  |
-        
-        // Transfer tokens.
-        // We do a raw call so we can check the success separate
-        // from the return data.
-        // We construct calldata for the `token.transferFrom` ABI.
-        // The layout of this calldata is in the table below.
-        // 
-        // | Area     | Offset | Length  | Contents                            |
-        // |----------|--------|---------|-------------------------------------|
-        // | Header   | 0      | 4       | function selector                   |
-        // | Params   |        | 3 * 32  | function parameters:                |
-        // |          | 4      |         |   1. from                           |
-        // |          | 36     |         |   2. to                             |
-        // |          | 68     |         |   3. amount                         |
-        
-        assembly {
-            /////// 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
-        view
-        returns (bytes4)
-    {
-        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 8d7cea717..000000000
--- a/packages/contracts/src/contracts/current/protocol/AssetProxy/ERC721Proxy.sol
+++ /dev/null
@@ -1,207 +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 "./interfaces/IAssetProxy.sol";
-import "./MixinAuthorizable.sol";
-
-contract ERC721Proxy is
-    IAssetProxy,
-    MixinAuthorizable
-{
-    // Id of this proxy.
-    bytes4 constant PROXY_ID = bytes4(keccak256("ERC721Token(address,uint256,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 transferFrom(
-        bytes assetData,
-        address from,
-        address to,
-        uint256 amount
-    )
-        external
-    {
-        require(
-            authorized[msg.sender],
-            "SENDER_NOT_AUTHORIZED"
-        );
-    
-        // `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               |
-
-        assembly {
-            // 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
-        view
-        returns (bytes4)
-    {
-        return PROXY_ID;
-    }
-}
diff --git a/packages/contracts/src/utils/artifacts.ts b/packages/contracts/src/utils/artifacts.ts
deleted file mode 100644
index d58e7973c..000000000
--- a/packages/contracts/src/utils/artifacts.ts
+++ /dev/null
@@ -1,49 +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 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,
-    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 8c9d0495d..5a0586c28 100644
--- a/packages/contracts/test/asset_proxy/authorizable.ts
+++ b/packages/contracts/test/asset_proxy/authorizable.ts
@@ -3,12 +3,12 @@ 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 { expectRevertReasonOrAlwaysFailingTransactionAsync } 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;
diff --git a/packages/contracts/test/asset_proxy/proxies.ts b/packages/contracts/test/asset_proxy/proxies.ts
index 39121d95c..fc1e53352 100644
--- a/packages/contracts/test/asset_proxy/proxies.ts
+++ b/packages/contracts/test/asset_proxy/proxies.ts
@@ -7,26 +7,32 @@ 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 { expectRevertReasonOrAlwaysFailingTransactionAsync } 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', () => {
@@ -105,14 +111,18 @@ describe('Asset Transfer Proxies', () => {
                 // 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(
-                        encodedAssetData,
-                        makerAddress,
-                        takerAddress,
-                        amount,
-                        { from: exchangeAddress },
-                    ),
+                    await web3Wrapper.sendTransactionAsync({
+                        to: erc20Proxy.address,
+                        data,
+                        from: exchangeAddress,
+                    }),
                     constants.AWAIT_TRANSACTION_MINED_MS,
                 );
                 // Verify transfer was successful
@@ -131,14 +141,18 @@ describe('Asset Transfer Proxies', () => {
                 // 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(
-                        encodedAssetData,
-                        makerAddress,
-                        takerAddress,
-                        amount,
-                        { from: exchangeAddress },
-                    ),
+                    await web3Wrapper.sendTransactionAsync({
+                        to: erc20Proxy.address,
+                        data,
+                        from: exchangeAddress,
+                    }),
                     constants.AWAIT_TRANSACTION_MINED_MS,
                 );
                 // Verify transfer was successful
@@ -156,7 +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,
@@ -165,13 +185,11 @@ describe('Asset Transfer Proxies', () => {
                 );
                 // Perform a transfer; expect this to fail.
                 return expectRevertReasonOrAlwaysFailingTransactionAsync(
-                    erc20Proxy.transferFrom.sendTransactionAsync(
-                        encodedAssetData,
-                        makerAddress,
-                        takerAddress,
-                        transferAmount,
-                        { from: exchangeAddress },
-                    ),
+                    web3Wrapper.sendTransactionAsync({
+                        to: erc20Proxy.address,
+                        data,
+                        from: exchangeAddress,
+                    }),
                     RevertReason.TransferFailed,
                 );
             });
@@ -179,11 +197,18 @@ describe('Asset Transfer Proxies', () => {
             it('should throw if requesting address is not authorized', async () => {
                 // Construct ERC20 asset data
                 const encodedAssetData = assetProxyUtils.encodeERC20AssetData(zrxToken.address);
-
                 // Perform a transfer from makerAddress to takerAddress
                 const amount = new BigNumber(10);
+                const data = assetProxyInterface.transferFrom.getABIEncodedTransactionData(
+                    encodedAssetData,
+                    makerAddress,
+                    takerAddress,
+                    amount,
+                );
                 return expectRevertReasonOrAlwaysFailingTransactionAsync(
-                    erc20Proxy.transferFrom.sendTransactionAsync(encodedAssetData, makerAddress, takerAddress, amount, {
+                    web3Wrapper.sendTransactionAsync({
+                        to: erc20Proxy.address,
+                        data,
                         from: notAuthorized,
                     }),
                     RevertReason.SenderNotAuthorized,
@@ -208,14 +233,18 @@ describe('Asset Transfer Proxies', () => {
                 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(
-                        encodedAssetData,
-                        makerAddress,
-                        takerAddress,
-                        amount,
-                        { from: exchangeAddress },
-                    ),
+                    await web3Wrapper.sendTransactionAsync({
+                        to: erc721Proxy.address,
+                        data,
+                        from: exchangeAddress,
+                    }),
                     constants.AWAIT_TRANSACTION_MINED_MS,
                 );
                 // Verify transfer was successful
@@ -231,17 +260,21 @@ describe('Asset Transfer Proxies', () => {
                 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(
+                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>;
@@ -266,17 +299,21 @@ describe('Asset Transfer Proxies', () => {
                 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(
+                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>;
@@ -301,14 +338,19 @@ describe('Asset Transfer Proxies', () => {
                 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,
+                    erc20Proxy.address, // the ERC20 proxy does not have an ERC721 receiver
+                    amount,
+                );
                 return expectRevertReasonOrAlwaysFailingTransactionAsync(
-                    erc721Proxy.transferFrom.sendTransactionAsync(
-                        encodedAssetData,
-                        makerAddress,
-                        erc20Proxy.address, // the ERC20 proxy does not have an ERC721 receiver
-                        amount,
-                        { from: exchangeAddress },
-                    ),
+                    web3Wrapper.sendTransactionAsync({
+                        to: erc721Proxy.address,
+                        data,
+                        from: exchangeAddress,
+                        gas: constants.TRANSFER_FROM_GAS,
+                    }),
                     RevertReason.TransferFailed,
                 );
             });
@@ -321,14 +363,18 @@ describe('Asset Transfer Proxies', () => {
                 expect(ownerMakerAsset).to.be.bignumber.equal(makerAddress);
                 // Perform a transfer from makerAddress to takerAddress
                 const amount = new BigNumber(0);
+                const data = assetProxyInterface.transferFrom.getABIEncodedTransactionData(
+                    encodedAssetData,
+                    makerAddress,
+                    takerAddress,
+                    amount,
+                );
                 return expectRevertReasonOrAlwaysFailingTransactionAsync(
-                    erc721Proxy.transferFrom.sendTransactionAsync(
-                        encodedAssetData,
-                        makerAddress,
-                        takerAddress,
-                        amount,
-                        { from: exchangeAddress },
-                    ),
+                    web3Wrapper.sendTransactionAsync({
+                        to: erc721Proxy.address,
+                        data,
+                        from: exchangeAddress,
+                    }),
                     RevertReason.InvalidAmount,
                 );
             });
@@ -341,14 +387,18 @@ describe('Asset Transfer Proxies', () => {
                 expect(ownerMakerAsset).to.be.bignumber.equal(makerAddress);
                 // Perform a transfer from makerAddress to takerAddress
                 const amount = new BigNumber(500);
+                const data = assetProxyInterface.transferFrom.getABIEncodedTransactionData(
+                    encodedAssetData,
+                    makerAddress,
+                    takerAddress,
+                    amount,
+                );
                 return expectRevertReasonOrAlwaysFailingTransactionAsync(
-                    erc721Proxy.transferFrom.sendTransactionAsync(
-                        encodedAssetData,
-                        makerAddress,
-                        takerAddress,
-                        amount,
-                        { from: exchangeAddress },
-                    ),
+                    web3Wrapper.sendTransactionAsync({
+                        to: erc721Proxy.address,
+                        data,
+                        from: exchangeAddress,
+                    }),
                     RevertReason.InvalidAmount,
                 );
             });
@@ -358,15 +408,23 @@ describe('Asset Transfer Proxies', () => {
                 const encodedAssetData = assetProxyUtils.encodeERC721AssetData(erc721Token.address, erc721MakerTokenId);
                 // 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);
+                const data = assetProxyInterface.transferFrom.getABIEncodedTransactionData(
+                    encodedAssetData,
+                    makerAddress,
+                    takerAddress,
+                    amount,
+                );
                 return expectRevertReasonOrAlwaysFailingTransactionAsync(
-                    erc20Proxy.transferFrom.sendTransactionAsync(encodedAssetData, makerAddress, takerAddress, amount, {
+                    web3Wrapper.sendTransactionAsync({
+                        to: erc721Proxy.address,
+                        data,
                         from: exchangeAddress,
                     }),
                     RevertReason.TransferFailed,
@@ -378,14 +436,18 @@ describe('Asset Transfer Proxies', () => {
                 const encodedAssetData = assetProxyUtils.encodeERC721AssetData(erc721Token.address, erc721MakerTokenId);
                 // Perform a transfer from makerAddress to takerAddress
                 const amount = new BigNumber(1);
+                const data = assetProxyInterface.transferFrom.getABIEncodedTransactionData(
+                    encodedAssetData,
+                    makerAddress,
+                    takerAddress,
+                    amount,
+                );
                 return expectRevertReasonOrAlwaysFailingTransactionAsync(
-                    erc721Proxy.transferFrom.sendTransactionAsync(
-                        encodedAssetData,
-                        makerAddress,
-                        takerAddress,
-                        amount,
-                        { from: notAuthorized },
-                    ),
+                    web3Wrapper.sendTransactionAsync({
+                        to: erc721Proxy.address,
+                        data,
+                        from: notAuthorized,
+                    }),
                     RevertReason.SenderNotAuthorized,
                 );
             });
diff --git a/packages/contracts/test/exchange/core.ts b/packages/contracts/test/exchange/core.ts
index 0c7381aac..db56623f9 100644
--- a/packages/contracts/test/exchange/core.ts
+++ b/packages/contracts/test/exchange/core.ts
@@ -1,6 +1,6 @@
 import { BlockchainLifecycle } from '@0xproject/dev-utils';
 import { assetProxyUtils, orderHashUtils } from '@0xproject/order-utils';
-import { AssetProxyId, RevertReason, 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';
@@ -8,21 +8,21 @@ 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 { 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 } from '../../src/generated_contract_wrappers/exchange';
-import { artifacts } from '../../src/utils/artifacts';
-import { expectRevertReasonOrAlwaysFailingTransactionAsync } 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 { 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;
@@ -90,8 +90,8 @@ describe('Exchange core', () => {
             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, {
diff --git a/packages/contracts/test/exchange/dispatcher.ts b/packages/contracts/test/exchange/dispatcher.ts
index e35cca845..afbf958d9 100644
--- a/packages/contracts/test/exchange/dispatcher.ts
+++ b/packages/contracts/test/exchange/dispatcher.ts
@@ -3,24 +3,29 @@ import { assetProxyUtils } from '@0xproject/order-utils';
 import { AssetProxyId, RevertReason } from '@0xproject/types';
 import { BigNumber } from '@0xproject/utils';
 import * as chai from 'chai';
+import { LogWithDecodedArgs } from 'ethereum-types';
 import * as _ from 'lodash';
 
-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 { expectRevertReasonOrAlwaysFailingTransactionAsync } 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 { 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;
@@ -82,14 +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);
@@ -98,46 +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(
@@ -146,114 +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 expectRevertReasonOrAlwaysFailingTransactionAsync(
-                assetProxyDispatcher.registerAssetProxy.sendTransactionAsync(
-                    AssetProxyId.ERC20,
-                    erc20Proxy.address,
-                    constants.NULL_ADDRESS,
-                    { from: owner },
-                ),
-                RevertReason.AssetProxyMismatch,
+                assetProxyDispatcher.registerAssetProxy.sendTransactionAsync(newErc20TransferProxy.address, {
+                    from: owner,
+                }),
+                RevertReason.AssetProxyAlreadyExists,
             );
         });
 
-        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,
-            );
-            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 expectRevertReasonOrAlwaysFailingTransactionAsync(
-                assetProxyDispatcher.registerAssetProxy.sendTransactionAsync(
-                    AssetProxyId.ERC20,
-                    erc20Proxy.address,
-                    prevProxyAddress,
-                    { from: notOwner },
-                ),
+                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 expectRevertReasonOrAlwaysFailingTransactionAsync(
-                assetProxyDispatcher.registerAssetProxy.sendTransactionAsync(
-                    AssetProxyId.ERC721,
-                    erc20Proxy.address,
-                    prevProxyAddress,
-                    { from: owner },
-                ),
-                RevertReason.AssetProxyIdMismatch,
+        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);
@@ -269,14 +175,8 @@ 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
@@ -323,3 +223,4 @@ describe('AssetProxyDispatcher', () => {
         });
     });
 });
+// tslint:enable:no-unnecessary-type-assertion
diff --git a/packages/contracts/test/exchange/fill_order.ts b/packages/contracts/test/exchange/fill_order.ts
index 7bf12809a..21d86622b 100644
--- a/packages/contracts/test/exchange/fill_order.ts
+++ b/packages/contracts/test/exchange/fill_order.ts
@@ -1,10 +1,8 @@
 import { BlockchainLifecycle } from '@0xproject/dev-utils';
 import * as _ from 'lodash';
 
-import { chaiSetup } from '../../src/utils/chai_setup';
-import { CoreCombinatorialUtils, coreCombinatorialUtilsFactoryAsync } from '../../src/utils/core_combinatorial_utils';
-import { provider, txDefaults, web3Wrapper } from '../../src/utils/web3_wrapper';
-
+import { chaiSetup } from '../utils/chai_setup';
+import { CoreCombinatorialUtils, coreCombinatorialUtilsFactoryAsync } from '../utils/core_combinatorial_utils';
 import {
     AllowanceAmountScenario,
     AssetDataScenario,
@@ -15,7 +13,8 @@ import {
     OrderAssetAmountScenario,
     TakerAssetFillAmountScenario,
     TakerScenario,
-} from '../../src/utils/types';
+} from '../utils/types';
+import { provider, txDefaults, web3Wrapper } from '../utils/web3_wrapper';
 
 chaiSetup.configure();
 const blockchainLifecycle = new BlockchainLifecycle(web3Wrapper);
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 e23ab9851..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, RevertReason } 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 { expectRevertReasonOrAlwaysFailingTransactionAsync } 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;
@@ -103,8 +103,8 @@ describe('matchOrders', () => {
             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, {
@@ -651,13 +651,7 @@ describe('matchOrders', () => {
             });
             // Match orders
             return expectRevertReasonOrAlwaysFailingTransactionAsync(
-                matchOrderTester.matchOrdersAndVerifyBalancesAsync(
-                    signedOrderLeft,
-                    signedOrderRight,
-                    takerAddress,
-                    erc20BalancesByOwner,
-                    erc721TokenIdsByOwner,
-                ),
+                exchangeWrapper.matchOrdersAsync(signedOrderLeft, signedOrderRight, takerAddress),
                 RevertReason.NegativeSpreadRequired,
             );
         });
@@ -680,13 +674,7 @@ describe('matchOrders', () => {
             });
             // Match orders
             return expectRevertReasonOrAlwaysFailingTransactionAsync(
-                matchOrderTester.matchOrdersAndVerifyBalancesAsync(
-                    signedOrderLeft,
-                    signedOrderRight,
-                    takerAddress,
-                    erc20BalancesByOwner,
-                    erc721TokenIdsByOwner,
-                ),
+                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
@@ -715,13 +703,7 @@ describe('matchOrders', () => {
             });
             // Match orders
             return expectRevertReasonOrAlwaysFailingTransactionAsync(
-                matchOrderTester.matchOrdersAndVerifyBalancesAsync(
-                    signedOrderLeft,
-                    signedOrderRight,
-                    takerAddress,
-                    erc20BalancesByOwner,
-                    erc721TokenIdsByOwner,
-                ),
+                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 21cc343b3..1db7dfc6d 100644
--- a/packages/contracts/test/exchange/signature_validator.ts
+++ b/packages/contracts/test/exchange/signature_validator.ts
@@ -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;
diff --git a/packages/contracts/test/exchange/transactions.ts b/packages/contracts/test/exchange/transactions.ts
index c4de58bb9..4f8b49e0e 100644
--- a/packages/contracts/test/exchange/transactions.ts
+++ b/packages/contracts/test/exchange/transactions.ts
@@ -1,26 +1,26 @@
 import { BlockchainLifecycle } from '@0xproject/dev-utils';
 import { assetProxyUtils, generatePseudoRandomSalt } from '@0xproject/order-utils';
-import { AssetProxyId, OrderWithoutExchangeAddress, RevertReason, SignedOrder } from '@0xproject/types';
+import { OrderWithoutExchangeAddress, RevertReason, SignedOrder } from '@0xproject/types';
 import { BigNumber } from '@0xproject/utils';
 import * as chai from 'chai';
 import * as _ from 'lodash';
 
-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 { expectRevertReasonOrAlwaysFailingTransactionAsync } 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 { 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;
@@ -91,7 +91,7 @@ describe('Exchange transactions', () => {
             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 }),
diff --git a/packages/contracts/test/exchange/wrapper.ts b/packages/contracts/test/exchange/wrapper.ts
index 1af8bde9d..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, RevertReason, 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 { expectRevertReasonOrAlwaysFailingTransactionAsync } 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;
@@ -87,8 +87,8 @@ describe('Exchange wrappers', () => {
             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, {
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 3d4058cbc..963b51b8f 100644
--- a/packages/contracts/test/libraries/lib_bytes.ts
+++ b/packages/contracts/test/libraries/lib_bytes.ts
@@ -7,12 +7,12 @@ 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;
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 0eb82b5fe..09a24950c 100644
--- a/packages/contracts/test/unlimited_allowance_token.ts
+++ b/packages/contracts/test/tokens/unlimited_allowance_token.ts
@@ -3,12 +3,12 @@ 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;
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/src/abstract/abstract_asset_wrapper.ts b/packages/contracts/test/utils/abstract_asset_wrapper.ts
index 4b56a8502..4b56a8502 100644
--- a/packages/contracts/src/abstract/abstract_asset_wrapper.ts
+++ b/packages/contracts/test/utils/abstract_asset_wrapper.ts
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 e702a3200..baba892d3 100644
--- a/packages/contracts/src/utils/assertions.ts
+++ b/packages/contracts/test/utils/assertions.ts
@@ -1,8 +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;
 
@@ -53,18 +55,45 @@ export function expectRevertOrAlwaysFailingTransactionAsync<T>(p: Promise<T>): P
 }
 
 /**
- * Rejects if the given Promise does not reject with the given revert reason or "always
- * failing transaction" error.
+ * 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 function expectRevertReasonOrAlwaysFailingTransactionAsync<T>(
-    p: Promise<T>,
+export async function expectRevertReasonOrAlwaysFailingTransactionAsync(
+    p: Promise<string | TransactionReceiptWithDecodedLogs | TransactionReceipt>,
     reason: RevertReason,
-): PromiseLike<void> {
-    return _expectEitherErrorAsync(p, 'always failing transaction', reason);
+): 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}`,
+            );
+        });
 }
 
 /**
diff --git a/packages/contracts/src/utils/asset_wrapper.ts b/packages/contracts/test/utils/asset_wrapper.ts
index 1a7b2b9ed..f291170a2 100644
--- a/packages/contracts/src/utils/asset_wrapper.ts
+++ b/packages/contracts/test/utils/asset_wrapper.ts
@@ -3,8 +3,7 @@ import { AssetProxyId } from '@0xproject/types';
 import { BigNumber, errorUtils } from '@0xproject/utils';
 import * as _ from 'lodash';
 
-import { AbstractAssetWrapper } from '../abstract/abstract_asset_wrapper';
-
+import { AbstractAssetWrapper } from './abstract_asset_wrapper';
 import { constants } from './constants';
 import { ERC20Wrapper } from './erc20_wrapper';
 import { ERC721Wrapper } from './erc721_wrapper';
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 2b2bd2425..8e68f376d 100644
--- a/packages/contracts/src/utils/constants.ts
+++ b/packages/contracts/test/utils/constants.ts
@@ -27,6 +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/src/utils/core_combinatorial_utils.ts b/packages/contracts/test/utils/core_combinatorial_utils.ts
index edcb050c6..86979b4ff 100644
--- a/packages/contracts/src/utils/core_combinatorial_utils.ts
+++ b/packages/contracts/test/utils/core_combinatorial_utils.ts
@@ -14,20 +14,21 @@ 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 '../utils/artifacts';
-import { expectRevertReasonOrAlwaysFailingTransactionAsync } from '../utils/assertions';
-import { AssetWrapper } from '../utils/asset_wrapper';
-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 { OrderFactoryFromScenario } from '../utils/order_factory_from_scenario';
-import { orderUtils } from '../utils/order_utils';
-import { signingUtils } from '../utils/signing_utils';
-import { SimpleAssetBalanceAndProxyAllowanceFetcher } from '../utils/simple_asset_balance_and_proxy_allowance_fetcher';
-import { SimpleOrderFilledCancelledFetcher } from '../utils/simple_order_filled_cancelled_fetcher';
+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,
@@ -39,7 +40,7 @@ import {
     TakerAssetFillAmountScenario,
     TakerScenario,
     TraderStateScenario,
-} from '../utils/types';
+} from './types';
 
 chaiSetup.configure();
 const expect = chai.expect;
@@ -96,8 +97,8 @@ export async function coreCombinatorialUtilsFactoryAsync(
         zrxAssetData,
     );
     const exchangeWrapper = new ExchangeWrapper(exchangeContract, provider);
-    await exchangeWrapper.registerAssetProxyAsync(AssetProxyId.ERC20, erc20Proxy.address, ownerAddress);
-    await exchangeWrapper.registerAssetProxyAsync(AssetProxyId.ERC721, erc721Proxy.address, ownerAddress);
+    await exchangeWrapper.registerAssetProxyAsync(erc20Proxy.address, ownerAddress);
+    await exchangeWrapper.registerAssetProxyAsync(erc721Proxy.address, ownerAddress);
 
     await web3Wrapper.awaitTransactionSuccessAsync(
         await erc20Proxy.addAuthorizedAddress.sendTransactionAsync(exchangeContract.address, {
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 7f00e2061..53e9791bc 100644
--- a/packages/contracts/src/utils/erc20_wrapper.ts
+++ b/packages/contracts/test/utils/erc20_wrapper.ts
@@ -4,8 +4,8 @@ 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';
diff --git a/packages/contracts/src/utils/erc721_wrapper.ts b/packages/contracts/test/utils/erc721_wrapper.ts
index 309135ae4..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';
diff --git a/packages/contracts/src/utils/exchange_wrapper.ts b/packages/contracts/test/utils/exchange_wrapper.ts
index ad68c8ff4..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';
@@ -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;
     }
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/src/utils/order_factory_from_scenario.ts b/packages/contracts/test/utils/order_factory_from_scenario.ts
index b150e59f6..9670c1a59 100644
--- a/packages/contracts/src/utils/order_factory_from_scenario.ts
+++ b/packages/contracts/test/utils/order_factory_from_scenario.ts
@@ -2,7 +2,7 @@ import { assetProxyUtils, generatePseudoRandomSalt } from '@0xproject/order-util
 import { Order } from '@0xproject/types';
 import { BigNumber, errorUtils } from '@0xproject/utils';
 
-import { DummyERC721TokenContract } from '../generated_contract_wrappers/dummy_e_r_c721_token';
+import { DummyERC721TokenContract } from '../../generated_contract_wrappers/dummy_e_r_c721_token';
 
 import { constants } from './constants';
 import {
diff --git a/packages/contracts/src/utils/order_utils.ts b/packages/contracts/test/utils/order_utils.ts
index 019f6e74b..019f6e74b 100644
--- a/packages/contracts/src/utils/order_utils.ts
+++ b/packages/contracts/test/utils/order_utils.ts
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/src/utils/simple_asset_balance_and_proxy_allowance_fetcher.ts b/packages/contracts/test/utils/simple_asset_balance_and_proxy_allowance_fetcher.ts
index a295a40c4..a295a40c4 100644
--- a/packages/contracts/src/utils/simple_asset_balance_and_proxy_allowance_fetcher.ts
+++ b/packages/contracts/test/utils/simple_asset_balance_and_proxy_allowance_fetcher.ts
diff --git a/packages/contracts/src/utils/simple_order_filled_cancelled_fetcher.ts b/packages/contracts/test/utils/simple_order_filled_cancelled_fetcher.ts
index 24afe36b7..24afe36b7 100644
--- a/packages/contracts/src/utils/simple_order_filled_cancelled_fetcher.ts
+++ b/packages/contracts/test/utils/simple_order_filled_cancelled_fetcher.ts
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 b792bb90a..b792bb90a 100644
--- a/packages/contracts/src/utils/types.ts
+++ b/packages/contracts/test/utils/types.ts
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