Merge branch 'v2-prototype' into bug/contracts/eip712-191-prefix

20 files changed, 1380 insertions, 608 deletions

diff --git a/packages/contracts/test/asset_proxy/authorizable.ts b/packages/contracts/test/asset_proxy/authorizable.ts
index e8274acb1..347d060d6 100644
--- a/packages/contracts/test/asset_proxy/authorizable.ts
+++ b/packages/contracts/test/asset_proxy/authorizable.ts
@@ -1,11 +1,10 @@
-import { BlockchainLifecycle, devConstants, web3Factory } from '@0xproject/dev-utils';
-import { Web3Wrapper } from '@0xproject/web3-wrapper';
+import { BlockchainLifecycle } from '@0xproject/dev-utils';
 import * as chai from 'chai';
 import 'make-promises-safe';
-import * as Web3 from 'web3';
 
-import { MixinAuthorizableContract } from '../../src/contract_wrappers/generated/mixin_authorizable';
+import { MixinAuthorizableContract } from '../../src/generated_contract_wrappers/mixin_authorizable';
 import { artifacts } from '../../src/utils/artifacts';
+import { expectRevertOrAlwaysFailingTransactionAsync } from '../../src/utils/assertions';
 import { chaiSetup } from '../../src/utils/chai_setup';
 import { constants } from '../../src/utils/constants';
 import { provider, txDefaults, web3Wrapper } from '../../src/utils/web3_wrapper';
@@ -44,9 +43,9 @@ describe('Authorizable', () => {
     });
     describe('addAuthorizedAddress', () => {
         it('should throw if not called by owner', async () => {
-            return expect(
+            return expectRevertOrAlwaysFailingTransactionAsync(
                 authorizable.addAuthorizedAddress.sendTransactionAsync(notOwner, { from: notOwner }),
-            ).to.be.rejectedWith(constants.REVERT);
+            );
         });
         it('should allow owner to add an authorized address', async () => {
             await web3Wrapper.awaitTransactionSuccessAsync(
@@ -61,9 +60,9 @@ describe('Authorizable', () => {
                 await authorizable.addAuthorizedAddress.sendTransactionAsync(address, { from: owner }),
                 constants.AWAIT_TRANSACTION_MINED_MS,
             );
-            return expect(
+            return expectRevertOrAlwaysFailingTransactionAsync(
                 authorizable.addAuthorizedAddress.sendTransactionAsync(address, { from: owner }),
-            ).to.be.rejectedWith(constants.REVERT);
+            );
         });
     });
 
@@ -73,11 +72,11 @@ describe('Authorizable', () => {
                 await authorizable.addAuthorizedAddress.sendTransactionAsync(address, { from: owner }),
                 constants.AWAIT_TRANSACTION_MINED_MS,
             );
-            return expect(
+            return expectRevertOrAlwaysFailingTransactionAsync(
                 authorizable.removeAuthorizedAddress.sendTransactionAsync(address, {
                     from: notOwner,
                 }),
-            ).to.be.rejectedWith(constants.REVERT);
+            );
         });
 
         it('should allow owner to remove an authorized address', async () => {
@@ -96,11 +95,11 @@ describe('Authorizable', () => {
         });
 
         it('should throw if owner attempts to remove an address that is not authorized', async () => {
-            return expect(
+            return expectRevertOrAlwaysFailingTransactionAsync(
                 authorizable.removeAuthorizedAddress.sendTransactionAsync(address, {
                     from: owner,
                 }),
-            ).to.be.rejectedWith(constants.REVERT);
+            );
         });
     });
 
diff --git a/packages/contracts/test/asset_proxy/decoder.ts b/packages/contracts/test/asset_proxy/decoder.ts
new file mode 100644
index 000000000..875d55daa
--- /dev/null
+++ b/packages/contracts/test/asset_proxy/decoder.ts
@@ -0,0 +1,86 @@
+import { BlockchainLifecycle } from '@0xproject/dev-utils';
+import { assetProxyUtils, generatePseudoRandomSalt } from '@0xproject/order-utils';
+import { BigNumber } from '@0xproject/utils';
+import * as chai from 'chai';
+import ethUtil = require('ethereumjs-util');
+
+import { TestAssetDataDecodersContract } from '../../src/generated_contract_wrappers/test_asset_data_decoders';
+import { artifacts } from '../../src/utils/artifacts';
+import { chaiSetup } from '../../src/utils/chai_setup';
+import { provider, txDefaults, web3Wrapper } from '../../src/utils/web3_wrapper';
+
+chaiSetup.configure();
+const expect = chai.expect;
+const blockchainLifecycle = new BlockchainLifecycle(web3Wrapper);
+
+describe('TestAssetDataDecoders', () => {
+    let testAssetProxyDecoder: TestAssetDataDecodersContract;
+    let testAddress: string;
+
+    before(async () => {
+        await blockchainLifecycle.startAsync();
+    });
+    after(async () => {
+        await blockchainLifecycle.revertAsync();
+    });
+    before(async () => {
+        // Setup accounts & addresses
+        const accounts = await web3Wrapper.getAvailableAddressesAsync();
+        testAddress = accounts[0];
+        // Deploy TestLibMem
+        testAssetProxyDecoder = await TestAssetDataDecodersContract.deployFrom0xArtifactAsync(
+            artifacts.TestAssetDataDecoders,
+            provider,
+            txDefaults,
+        );
+    });
+    beforeEach(async () => {
+        await blockchainLifecycle.startAsync();
+    });
+    afterEach(async () => {
+        await blockchainLifecycle.revertAsync();
+    });
+
+    describe('Asset Data Decoders', () => {
+        it('should correctly decode ERC721 asset data', async () => {
+            const tokenId = generatePseudoRandomSalt();
+            const encodedAssetData = assetProxyUtils.encodeERC721AssetData(testAddress, tokenId);
+            const encodedAssetDataWithoutProxyId = encodedAssetData.slice(0, -2);
+            const expectedDecodedAssetData = assetProxyUtils.decodeERC721AssetData(encodedAssetData);
+            let decodedTokenAddress: string;
+            let decodedTokenId: BigNumber;
+            let decodedData: string;
+            [
+                decodedTokenAddress,
+                decodedTokenId,
+                decodedData,
+            ] = await testAssetProxyDecoder.publicDecodeERC721Data.callAsync(encodedAssetDataWithoutProxyId);
+            expect(decodedTokenAddress).to.be.equal(expectedDecodedAssetData.tokenAddress);
+            expect(decodedTokenId).to.be.bignumber.equal(expectedDecodedAssetData.tokenId);
+            expect(decodedData).to.be.equal(expectedDecodedAssetData.receiverData);
+        });
+
+        it('should correctly decode ERC721 asset data with receiver data', async () => {
+            const tokenId = generatePseudoRandomSalt();
+            const receiverDataFirst32Bytes = ethUtil.bufferToHex(
+                assetProxyUtils.encodeUint256(generatePseudoRandomSalt()),
+            );
+            const receiverDataExtraBytes = 'FFFF';
+            // We add extra bytes to generate a value that doesn't fit perfectly into one word
+            const receiverData = receiverDataFirst32Bytes + receiverDataExtraBytes;
+            const encodedAssetData = assetProxyUtils.encodeERC721AssetData(testAddress, tokenId, receiverData);
+            const expectedDecodedAssetData = assetProxyUtils.decodeERC721AssetData(encodedAssetData);
+            let decodedTokenAddress: string;
+            let decodedTokenId: BigNumber;
+            let decodedReceiverData: string;
+            [
+                decodedTokenAddress,
+                decodedTokenId,
+                decodedReceiverData,
+            ] = await testAssetProxyDecoder.publicDecodeERC721Data.callAsync(encodedAssetData);
+            expect(decodedTokenAddress).to.be.equal(expectedDecodedAssetData.tokenAddress);
+            expect(decodedTokenId).to.be.bignumber.equal(expectedDecodedAssetData.tokenId);
+            expect(decodedReceiverData).to.be.equal(expectedDecodedAssetData.receiverData);
+        });
+    });
+});
diff --git a/packages/contracts/test/asset_proxy/proxies.ts b/packages/contracts/test/asset_proxy/proxies.ts
index faab39759..9760d3b9c 100644
--- a/packages/contracts/test/asset_proxy/proxies.ts
+++ b/packages/contracts/test/asset_proxy/proxies.ts
@@ -1,25 +1,33 @@
 import { BlockchainLifecycle } from '@0xproject/dev-utils';
-import { assetProxyUtils } from '@0xproject/order-utils';
-import { AssetProxyId } from '@0xproject/types';
+import { assetProxyUtils, generatePseudoRandomSalt } from '@0xproject/order-utils';
 import { BigNumber } from '@0xproject/utils';
 import * as chai from 'chai';
+import { LogWithDecodedArgs } from 'ethereum-types';
+import ethUtil = require('ethereumjs-util');
 import * as _ from 'lodash';
-import * as Web3 from 'web3';
 
-import { DummyERC20TokenContract } from '../../src/contract_wrappers/generated/dummy_e_r_c20_token';
-import { DummyERC721TokenContract } from '../../src/contract_wrappers/generated/dummy_e_r_c721_token';
-import { ERC20ProxyContract } from '../../src/contract_wrappers/generated/e_r_c20_proxy';
-import { ERC721ProxyContract } from '../../src/contract_wrappers/generated/e_r_c721_proxy';
+import { DummyERC20TokenContract } from '../../src/generated_contract_wrappers/dummy_e_r_c20_token';
+import {
+    DummyERC721ReceiverContract,
+    TokenReceivedContractEventArgs,
+} from '../../src/generated_contract_wrappers/dummy_e_r_c721_receiver';
+import { DummyERC721TokenContract } from '../../src/generated_contract_wrappers/dummy_e_r_c721_token';
+import { ERC20ProxyContract } from '../../src/generated_contract_wrappers/e_r_c20_proxy';
+import { ERC721ProxyContract } from '../../src/generated_contract_wrappers/e_r_c721_proxy';
+import { artifacts } from '../../src/utils/artifacts';
+import { expectRevertOrAlwaysFailingTransactionAsync } from '../../src/utils/assertions';
 import { chaiSetup } from '../../src/utils/chai_setup';
 import { constants } from '../../src/utils/constants';
 import { ERC20Wrapper } from '../../src/utils/erc20_wrapper';
 import { ERC721Wrapper } from '../../src/utils/erc721_wrapper';
-import { provider, web3Wrapper } from '../../src/utils/web3_wrapper';
+import { LogDecoder } from '../../src/utils/log_decoder';
+import { provider, txDefaults, web3Wrapper } from '../../src/utils/web3_wrapper';
 
 chaiSetup.configure();
 const expect = chai.expect;
 const blockchainLifecycle = new BlockchainLifecycle(web3Wrapper);
 
+// tslint:disable:no-unnecessary-type-assertion
 describe('Asset Transfer Proxies', () => {
     let owner: string;
     let notAuthorized: string;
@@ -29,6 +37,7 @@ describe('Asset Transfer Proxies', () => {
 
     let zrxToken: DummyERC20TokenContract;
     let erc721Token: DummyERC721TokenContract;
+    let erc721Receiver: DummyERC721ReceiverContract;
     let erc20Proxy: ERC20ProxyContract;
     let erc721Proxy: ERC721ProxyContract;
 
@@ -70,6 +79,11 @@ describe('Asset Transfer Proxies', () => {
             }),
             constants.AWAIT_TRANSACTION_MINED_MS,
         );
+        erc721Receiver = await DummyERC721ReceiverContract.deployFrom0xArtifactAsync(
+            artifacts.DummyERC721Receiver,
+            provider,
+            txDefaults,
+        );
     });
     beforeEach(async () => {
         await blockchainLifecycle.startAsync();
@@ -80,14 +94,15 @@ describe('Asset Transfer Proxies', () => {
     describe('Transfer Proxy - ERC20', () => {
         describe('transferFrom', () => {
             it('should successfully transfer tokens', async () => {
-                // Construct metadata for ERC20 proxy
-                const encodedProxyMetadata = assetProxyUtils.encodeERC20ProxyData(zrxToken.address);
+                // Construct ERC20 asset data
+                const encodedAssetData = assetProxyUtils.encodeERC20AssetData(zrxToken.address);
+                const encodedAssetDataWithoutProxyId = encodedAssetData.slice(0, -2);
                 // Perform a transfer from makerAddress to takerAddress
                 const erc20Balances = await erc20Wrapper.getBalancesAsync();
                 const amount = new BigNumber(10);
                 await web3Wrapper.awaitTransactionSuccessAsync(
                     await erc20Proxy.transferFrom.sendTransactionAsync(
-                        encodedProxyMetadata,
+                        encodedAssetDataWithoutProxyId,
                         makerAddress,
                         takerAddress,
                         amount,
@@ -106,14 +121,15 @@ describe('Asset Transfer Proxies', () => {
             });
 
             it('should do nothing if transferring 0 amount of a token', async () => {
-                // Construct metadata for ERC20 proxy
-                const encodedProxyMetadata = assetProxyUtils.encodeERC20ProxyData(zrxToken.address);
+                // Construct ERC20 asset data
+                const encodedAssetData = assetProxyUtils.encodeERC20AssetData(zrxToken.address);
+                const encodedAssetDataWithoutProxyId = encodedAssetData.slice(0, -2);
                 // Perform a transfer from makerAddress to takerAddress
                 const erc20Balances = await erc20Wrapper.getBalancesAsync();
                 const amount = new BigNumber(0);
                 await web3Wrapper.awaitTransactionSuccessAsync(
                     await erc20Proxy.transferFrom.sendTransactionAsync(
-                        encodedProxyMetadata,
+                        encodedAssetDataWithoutProxyId,
                         makerAddress,
                         takerAddress,
                         amount,
@@ -132,8 +148,8 @@ describe('Asset Transfer Proxies', () => {
             });
 
             it('should throw if allowances are too low', async () => {
-                // Construct metadata for ERC20 proxy
-                const encodedProxyMetadata = assetProxyUtils.encodeERC20ProxyData(zrxToken.address);
+                // Construct ERC20 asset data
+                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);
@@ -144,25 +160,26 @@ describe('Asset Transfer Proxies', () => {
                     constants.AWAIT_TRANSACTION_MINED_MS,
                 );
                 // Perform a transfer; expect this to fail.
-                return expect(
+                return expectRevertOrAlwaysFailingTransactionAsync(
                     erc20Proxy.transferFrom.sendTransactionAsync(
-                        encodedProxyMetadata,
+                        encodedAssetData,
                         makerAddress,
                         takerAddress,
                         transferAmount,
                         { from: notAuthorized },
                     ),
-                ).to.be.rejectedWith(constants.REVERT);
+                );
             });
 
             it('should throw if requesting address is not authorized', async () => {
-                // Construct metadata for ERC20 proxy
-                const encodedProxyMetadata = assetProxyUtils.encodeERC20ProxyData(zrxToken.address);
+                // Construct ERC20 asset data
+                const encodedAssetData = assetProxyUtils.encodeERC20AssetData(zrxToken.address);
+                const encodedAssetDataWithoutProxyId = encodedAssetData.slice(0, -2);
                 // Perform a transfer from makerAddress to takerAddress
                 const amount = new BigNumber(10);
-                return expect(
+                return expectRevertOrAlwaysFailingTransactionAsync(
                     erc20Proxy.transferFrom.sendTransactionAsync(
-                        encodedProxyMetadata,
+                        encodedAssetDataWithoutProxyId,
                         makerAddress,
                         takerAddress,
                         amount,
@@ -170,7 +187,7 @@ describe('Asset Transfer Proxies', () => {
                             from: notAuthorized,
                         },
                     ),
-                ).to.be.rejectedWith(constants.REVERT);
+                );
             });
         });
 
@@ -178,16 +195,17 @@ describe('Asset Transfer Proxies', () => {
             it('should succesfully make multiple token transfers', async () => {
                 const erc20Balances = await erc20Wrapper.getBalancesAsync();
 
-                const encodedProxyMetadata = assetProxyUtils.encodeERC20ProxyData(zrxToken.address);
+                const encodedAssetData = assetProxyUtils.encodeERC20AssetData(zrxToken.address);
+                const encodedAssetDataWithoutProxyId = encodedAssetData.slice(0, -2);
                 const amount = new BigNumber(10);
                 const numTransfers = 2;
-                const assetMetadata = _.times(numTransfers, () => encodedProxyMetadata);
+                const assetData = _.times(numTransfers, () => encodedAssetDataWithoutProxyId);
                 const fromAddresses = _.times(numTransfers, () => makerAddress);
                 const toAddresses = _.times(numTransfers, () => takerAddress);
                 const amounts = _.times(numTransfers, () => amount);
 
                 const txHash = await erc20Proxy.batchTransferFrom.sendTransactionAsync(
-                    assetMetadata,
+                    assetData,
                     fromAddresses,
                     toAddresses,
                     amounts,
@@ -209,23 +227,20 @@ describe('Asset Transfer Proxies', () => {
             });
 
             it('should throw if not called by an authorized address', async () => {
-                const encodedProxyMetadata = assetProxyUtils.encodeERC20ProxyData(zrxToken.address);
+                const encodedAssetData = assetProxyUtils.encodeERC20AssetData(zrxToken.address);
+                const encodedAssetDataWithoutProxyId = encodedAssetData.slice(0, -2);
                 const amount = new BigNumber(10);
                 const numTransfers = 2;
-                const assetMetadata = _.times(numTransfers, () => encodedProxyMetadata);
+                const assetData = _.times(numTransfers, () => encodedAssetDataWithoutProxyId);
                 const fromAddresses = _.times(numTransfers, () => makerAddress);
                 const toAddresses = _.times(numTransfers, () => takerAddress);
                 const amounts = _.times(numTransfers, () => amount);
 
-                return expect(
-                    erc20Proxy.batchTransferFrom.sendTransactionAsync(
-                        assetMetadata,
-                        fromAddresses,
-                        toAddresses,
-                        amounts,
-                        { from: notAuthorized },
-                    ),
-                ).to.be.rejectedWith(constants.REVERT);
+                return expectRevertOrAlwaysFailingTransactionAsync(
+                    erc20Proxy.batchTransferFrom.sendTransactionAsync(assetData, fromAddresses, toAddresses, amounts, {
+                        from: notAuthorized,
+                    }),
+                );
             });
         });
 
@@ -238,20 +253,17 @@ describe('Asset Transfer Proxies', () => {
     describe('Transfer Proxy - ERC721', () => {
         describe('transferFrom', () => {
             it('should successfully transfer tokens', async () => {
-                // Construct metadata for ERC721 proxy
-                const encodedProxyMetadata = assetProxyUtils.encodeERC721ProxyData(
-                    erc721Token.address,
-                    erc721MakerTokenId,
-                );
+                // Construct ERC721 asset data
+                const encodedAssetData = assetProxyUtils.encodeERC721AssetData(erc721Token.address, erc721MakerTokenId);
+                const encodedAssetDataWithoutProxyId = encodedAssetData.slice(0, -2);
                 // Verify pre-condition
                 const ownerMakerAsset = await erc721Token.ownerOf.callAsync(erc721MakerTokenId);
                 expect(ownerMakerAsset).to.be.bignumber.equal(makerAddress);
                 // Perform a transfer from makerAddress to takerAddress
-                const erc20Balances = await erc20Wrapper.getBalancesAsync();
                 const amount = new BigNumber(1);
                 await web3Wrapper.awaitTransactionSuccessAsync(
                     await erc721Proxy.transferFrom.sendTransactionAsync(
-                        encodedProxyMetadata,
+                        encodedAssetDataWithoutProxyId,
                         makerAddress,
                         takerAddress,
                         amount,
@@ -264,58 +276,138 @@ describe('Asset Transfer Proxies', () => {
                 expect(newOwnerMakerAsset).to.be.bignumber.equal(takerAddress);
             });
 
-            it('should throw if transferring 0 amount of a token', async () => {
-                // Construct metadata for ERC721 proxy
-                const encodedProxyMetadata = assetProxyUtils.encodeERC721ProxyData(
+            it('should not call onERC721Received when transferring to a smart contract without receiver data', async () => {
+                // Construct ERC721 asset data
+                const encodedAssetData = assetProxyUtils.encodeERC721AssetData(erc721Token.address, erc721MakerTokenId);
+                const encodedAssetDataWithoutProxyId = encodedAssetData.slice(0, -2);
+                // Verify pre-condition
+                const ownerMakerAsset = await erc721Token.ownerOf.callAsync(erc721MakerTokenId);
+                expect(ownerMakerAsset).to.be.bignumber.equal(makerAddress);
+                // Perform a transfer from makerAddress to takerAddress
+                const amount = new BigNumber(1);
+                const txHash = await erc721Proxy.transferFrom.sendTransactionAsync(
+                    encodedAssetDataWithoutProxyId,
+                    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);
+                // Verify that no log was emitted by erc721 receiver
+                expect(tx.logs.length).to.be.equal(0);
+                // Verify transfer was successful
+                const newOwnerMakerAsset = await erc721Token.ownerOf.callAsync(erc721MakerTokenId);
+                expect(newOwnerMakerAsset).to.be.bignumber.equal(erc721Receiver.address);
+            });
+
+            it('should call onERC721Received when transferring to a smart contract with receiver data', async () => {
+                // Construct ERC721 asset data
+                const receiverData = ethUtil.bufferToHex(assetProxyUtils.encodeUint256(generatePseudoRandomSalt()));
+                const encodedAssetData = assetProxyUtils.encodeERC721AssetData(
                     erc721Token.address,
                     erc721MakerTokenId,
+                    receiverData,
                 );
+                const encodedAssetDataWithoutProxyId = encodedAssetData.slice(0, -2);
+                // Verify pre-condition
+                const ownerMakerAsset = await erc721Token.ownerOf.callAsync(erc721MakerTokenId);
+                expect(ownerMakerAsset).to.be.bignumber.equal(makerAddress);
+                // Perform a transfer from makerAddress to takerAddress
+                const amount = new BigNumber(1);
+                const txHash = await erc721Proxy.transferFrom.sendTransactionAsync(
+                    encodedAssetDataWithoutProxyId,
+                    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);
+                // Validate log emitted by erc721 receiver
+                expect(tx.logs.length).to.be.equal(1);
+                const tokenReceivedLog = tx.logs[0] as LogWithDecodedArgs<TokenReceivedContractEventArgs>;
+                expect(tokenReceivedLog.args.from).to.be.equal(makerAddress);
+                expect(tokenReceivedLog.args.tokenId).to.be.bignumber.equal(erc721MakerTokenId);
+                expect(tokenReceivedLog.args.data).to.be.equal(receiverData);
+                // Verify transfer was successful
+                const newOwnerMakerAsset = await erc721Token.ownerOf.callAsync(erc721MakerTokenId);
+                expect(newOwnerMakerAsset).to.be.bignumber.equal(erc721Receiver.address);
+            });
+
+            it('should throw if there is receiver data but contract does not have onERC721Received', async () => {
+                // Construct ERC721 asset data
+                const receiverData = ethUtil.bufferToHex(assetProxyUtils.encodeUint256(generatePseudoRandomSalt()));
+                const encodedAssetData = assetProxyUtils.encodeERC721AssetData(
+                    erc721Token.address,
+                    erc721MakerTokenId,
+                    receiverData,
+                );
+                const encodedAssetDataWithoutProxyId = encodedAssetData.slice(0, -2);
+                // Verify pre-condition
+                const ownerMakerAsset = await erc721Token.ownerOf.callAsync(erc721MakerTokenId);
+                expect(ownerMakerAsset).to.be.bignumber.equal(makerAddress);
+                // Perform a transfer from makerAddress to takerAddress
+                const amount = new BigNumber(1);
+                return expectRevertOrAlwaysFailingTransactionAsync(
+                    erc721Proxy.transferFrom.sendTransactionAsync(
+                        encodedAssetDataWithoutProxyId,
+                        makerAddress,
+                        erc20Proxy.address, // the ERC20 proxy does not have an ERC721 receiver
+                        amount,
+                        { from: exchangeAddress },
+                    ),
+                );
+            });
+
+            it('should throw if transferring 0 amount of a token', async () => {
+                // Construct ERC721 asset data
+                const encodedAssetData = assetProxyUtils.encodeERC721AssetData(erc721Token.address, erc721MakerTokenId);
+                const encodedAssetDataWithoutProxyId = encodedAssetData.slice(0, -2);
                 // Verify pre-condition
                 const ownerMakerAsset = await erc721Token.ownerOf.callAsync(erc721MakerTokenId);
                 expect(ownerMakerAsset).to.be.bignumber.equal(makerAddress);
                 // Perform a transfer from makerAddress to takerAddress
-                const erc20Balances = await erc20Wrapper.getBalancesAsync();
                 const amount = new BigNumber(0);
-                return expect(
+                return expectRevertOrAlwaysFailingTransactionAsync(
                     erc721Proxy.transferFrom.sendTransactionAsync(
-                        encodedProxyMetadata,
+                        encodedAssetDataWithoutProxyId,
                         makerAddress,
                         takerAddress,
                         amount,
                         { from: exchangeAddress },
                     ),
-                ).to.be.rejectedWith(constants.REVERT);
+                );
             });
 
             it('should throw if transferring > 1 amount of a token', async () => {
-                // Construct metadata for ERC721 proxy
-                const encodedProxyMetadata = assetProxyUtils.encodeERC721ProxyData(
-                    erc721Token.address,
-                    erc721MakerTokenId,
-                );
+                // Construct ERC721 asset data
+                const encodedAssetData = assetProxyUtils.encodeERC721AssetData(erc721Token.address, erc721MakerTokenId);
+                const encodedAssetDataWithoutProxyId = encodedAssetData.slice(0, -2);
                 // Verify pre-condition
                 const ownerMakerAsset = await erc721Token.ownerOf.callAsync(erc721MakerTokenId);
                 expect(ownerMakerAsset).to.be.bignumber.equal(makerAddress);
                 // Perform a transfer from makerAddress to takerAddress
-                const erc20Balances = await erc20Wrapper.getBalancesAsync();
                 const amount = new BigNumber(500);
-                return expect(
+                return expectRevertOrAlwaysFailingTransactionAsync(
                     erc721Proxy.transferFrom.sendTransactionAsync(
-                        encodedProxyMetadata,
+                        encodedAssetDataWithoutProxyId,
                         makerAddress,
                         takerAddress,
                         amount,
                         { from: exchangeAddress },
                     ),
-                ).to.be.rejectedWith(constants.REVERT);
+                );
             });
 
             it('should throw if allowances are too low', async () => {
-                // Construct metadata for ERC721 proxy
-                const encodedProxyMetadata = assetProxyUtils.encodeERC721ProxyData(
-                    erc721Token.address,
-                    erc721MakerTokenId,
-                );
+                // Construct ERC721 asset data
+                const encodedAssetData = assetProxyUtils.encodeERC721AssetData(erc721Token.address, erc721MakerTokenId);
+                const encodedAssetDataWithoutProxyId = encodedAssetData.slice(0, -2);
                 // Remove transfer approval for makerAddress.
                 await web3Wrapper.awaitTransactionSuccessAsync(
                     await erc721Token.setApprovalForAll.sendTransactionAsync(erc721Proxy.address, false, {
@@ -325,9 +417,9 @@ describe('Asset Transfer Proxies', () => {
                 );
                 // Perform a transfer; expect this to fail.
                 const amount = new BigNumber(1);
-                return expect(
+                return expectRevertOrAlwaysFailingTransactionAsync(
                     erc20Proxy.transferFrom.sendTransactionAsync(
-                        encodedProxyMetadata,
+                        encodedAssetDataWithoutProxyId,
                         makerAddress,
                         takerAddress,
                         amount,
@@ -335,26 +427,24 @@ describe('Asset Transfer Proxies', () => {
                             from: notAuthorized,
                         },
                     ),
-                ).to.be.rejectedWith(constants.REVERT);
+                );
             });
 
             it('should throw if requesting address is not authorized', async () => {
-                // Construct metadata for ERC721 proxy
-                const encodedProxyMetadata = assetProxyUtils.encodeERC721ProxyData(
-                    erc721Token.address,
-                    erc721MakerTokenId,
-                );
+                // Construct ERC721 asset data
+                const encodedAssetData = assetProxyUtils.encodeERC721AssetData(erc721Token.address, erc721MakerTokenId);
+                const encodedAssetDataWithoutProxyId = encodedAssetData.slice(0, -2);
                 // Perform a transfer from makerAddress to takerAddress
                 const amount = new BigNumber(1);
-                return expect(
+                return expectRevertOrAlwaysFailingTransactionAsync(
                     erc721Proxy.transferFrom.sendTransactionAsync(
-                        encodedProxyMetadata,
+                        encodedAssetDataWithoutProxyId,
                         makerAddress,
                         takerAddress,
                         amount,
                         { from: notAuthorized },
                     ),
-                ).to.be.rejectedWith(constants.REVERT);
+                );
             });
         });
 
@@ -364,16 +454,16 @@ describe('Asset Transfer Proxies', () => {
                 const [makerTokenIdA, makerTokenIdB] = erc721TokensById[makerAddress][erc721Token.address];
 
                 const numTransfers = 2;
-                const assetMetadata = [
-                    assetProxyUtils.encodeERC721ProxyData(erc721Token.address, makerTokenIdA),
-                    assetProxyUtils.encodeERC721ProxyData(erc721Token.address, makerTokenIdB),
+                const assetData = [
+                    assetProxyUtils.encodeERC721AssetData(erc721Token.address, makerTokenIdA).slice(0, -2),
+                    assetProxyUtils.encodeERC721AssetData(erc721Token.address, makerTokenIdB).slice(0, -2),
                 ];
                 const fromAddresses = _.times(numTransfers, () => makerAddress);
                 const toAddresses = _.times(numTransfers, () => takerAddress);
                 const amounts = _.times(numTransfers, () => new BigNumber(1));
 
                 const txHash = await erc721Proxy.batchTransferFrom.sendTransactionAsync(
-                    assetMetadata,
+                    assetData,
                     fromAddresses,
                     toAddresses,
                     amounts,
@@ -396,23 +486,19 @@ describe('Asset Transfer Proxies', () => {
                 const [makerTokenIdA, makerTokenIdB] = erc721TokensById[makerAddress][erc721Token.address];
 
                 const numTransfers = 2;
-                const assetMetadata = [
-                    assetProxyUtils.encodeERC721ProxyData(erc721Token.address, makerTokenIdA),
-                    assetProxyUtils.encodeERC721ProxyData(erc721Token.address, makerTokenIdB),
+                const assetData = [
+                    assetProxyUtils.encodeERC721AssetData(erc721Token.address, makerTokenIdA).slice(0, -2),
+                    assetProxyUtils.encodeERC721AssetData(erc721Token.address, makerTokenIdB).slice(0, -2),
                 ];
                 const fromAddresses = _.times(numTransfers, () => makerAddress);
                 const toAddresses = _.times(numTransfers, () => takerAddress);
                 const amounts = _.times(numTransfers, () => new BigNumber(1));
 
-                return expect(
-                    erc721Proxy.batchTransferFrom.sendTransactionAsync(
-                        assetMetadata,
-                        fromAddresses,
-                        toAddresses,
-                        amounts,
-                        { from: notAuthorized },
-                    ),
-                ).to.be.rejectedWith(constants.REVERT);
+                return expectRevertOrAlwaysFailingTransactionAsync(
+                    erc721Proxy.batchTransferFrom.sendTransactionAsync(assetData, fromAddresses, toAddresses, amounts, {
+                        from: notAuthorized,
+                    }),
+                );
             });
         });
 
@@ -422,3 +508,5 @@ describe('Asset Transfer Proxies', () => {
         });
     });
 });
+// tslint:enable:no-unnecessary-type-assertion
+// tslint:disable:max-file-line-count
diff --git a/packages/contracts/test/asset_proxy_owner.ts b/packages/contracts/test/asset_proxy_owner.ts
index 4c16b5cff..cbe429b12 100644
--- a/packages/contracts/test/asset_proxy_owner.ts
+++ b/packages/contracts/test/asset_proxy_owner.ts
@@ -2,9 +2,7 @@ import { BlockchainLifecycle } from '@0xproject/dev-utils';
 import { BigNumber } from '@0xproject/utils';
 import * as chai from 'chai';
 import { LogWithDecodedArgs } from 'ethereum-types';
-import * as _ from 'lodash';
 import 'make-promises-safe';
-import * as Web3 from 'web3';
 
 import {
     AssetProxyOwnerContract,
@@ -12,18 +10,23 @@ import {
     ExecutionContractEventArgs,
     ExecutionFailureContractEventArgs,
     SubmissionContractEventArgs,
-} from '../src/contract_wrappers/generated/asset_proxy_owner';
-import { MixinAuthorizableContract } from '../src/contract_wrappers/generated/mixin_authorizable';
+} from '../src/generated_contract_wrappers/asset_proxy_owner';
+import { MixinAuthorizableContract } from '../src/generated_contract_wrappers/mixin_authorizable';
 import { artifacts } from '../src/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';
 
 chaiSetup.configure();
 const expect = chai.expect;
 const blockchainLifecycle = new BlockchainLifecycle(web3Wrapper);
-
+// tslint:disable:no-unnecessary-type-assertion
 describe('AssetProxyOwner', () => {
     let owners: string[];
     let authorized: string;
@@ -101,7 +104,7 @@ describe('AssetProxyOwner', () => {
         });
         it('should throw if a null address is included in assetProxyContracts', async () => {
             const assetProxyContractAddresses = [erc20Proxy.address, constants.NULL_ADDRESS];
-            return expect(
+            return expectRevertOrAlwaysFailingTransactionAsync(
                 AssetProxyOwnerContract.deployFrom0xArtifactAsync(
                     artifacts.AssetProxyOwner,
                     provider,
@@ -111,7 +114,7 @@ describe('AssetProxyOwner', () => {
                     REQUIRED_APPROVALS,
                     SECONDS_TIME_LOCKED,
                 ),
-            ).to.be.rejectedWith(constants.REVERT);
+            );
         });
     });
 
@@ -120,9 +123,9 @@ describe('AssetProxyOwner', () => {
             const notRemoveAuthorizedAddressData = erc20Proxy.addAuthorizedAddress.getABIEncodedTransactionData(
                 owners[0],
             );
-            return expect(
+            return expectRevertOrContractCallFailedAsync(
                 multiSig.isFunctionRemoveAuthorizedAddress.callAsync(notRemoveAuthorizedAddressData),
-            ).to.be.rejectedWith(constants.REVERT);
+            );
         });
 
         it('should return true if data is for removeAuthorizedAddress', async () => {
@@ -139,9 +142,9 @@ describe('AssetProxyOwner', () => {
     describe('registerAssetProxy', () => {
         it('should throw if not called by multisig', async () => {
             const isRegistered = true;
-            return expect(
+            return expectRevertOrAlwaysFailingTransactionAsync(
                 multiSig.registerAssetProxy.sendTransactionAsync(erc20Proxy.address, isRegistered, { from: owners[0] }),
-            ).to.be.rejectedWith(constants.REVERT);
+            );
         });
 
         it('should register an address if called by multisig after timelock', async () => {
@@ -156,11 +159,12 @@ describe('AssetProxyOwner', () => {
                 registerAssetProxyData,
                 owners[0],
             );
+
             const log = submitTxRes.logs[0] as LogWithDecodedArgs<SubmissionContractEventArgs>;
             const txId = log.args.transactionId;
 
             await multiSigWrapper.confirmTransactionAsync(txId, owners[1]);
-            await web3Wrapper.increaseTimeAsync(SECONDS_TIME_LOCKED.toNumber());
+            await increaseTimeAndMineBlockAsync(SECONDS_TIME_LOCKED.toNumber());
 
             const executeTxRes = await multiSigWrapper.executeTransactionAsync(txId, owners[0]);
             const registerLog = executeTxRes.logs[0] as LogWithDecodedArgs<AssetProxyRegistrationContractEventArgs>;
@@ -187,7 +191,7 @@ describe('AssetProxyOwner', () => {
             const txId = log.args.transactionId;
 
             await multiSigWrapper.confirmTransactionAsync(txId, owners[1]);
-            await web3Wrapper.increaseTimeAsync(SECONDS_TIME_LOCKED.toNumber());
+            await increaseTimeAndMineBlockAsync(SECONDS_TIME_LOCKED.toNumber());
 
             const executeTxRes = await multiSigWrapper.executeTransactionAsync(txId, owners[0]);
             const failureLog = executeTxRes.logs[0] as LogWithDecodedArgs<ExecutionFailureContractEventArgs>;
@@ -239,7 +243,7 @@ describe('AssetProxyOwner', () => {
 
             await multiSigWrapper.confirmTransactionAsync(erc20AddAuthorizedAddressTxId, owners[1]);
             await multiSigWrapper.confirmTransactionAsync(erc721AddAuthorizedAddressTxId, owners[1]);
-            await web3Wrapper.increaseTimeAsync(SECONDS_TIME_LOCKED.toNumber());
+            await increaseTimeAndMineBlockAsync(SECONDS_TIME_LOCKED.toNumber());
             await multiSigWrapper.executeTransactionAsync(registerAssetProxyTxId, owners[0]);
             await multiSigWrapper.executeTransactionAsync(erc20AddAuthorizedAddressTxId, owners[0]);
             await multiSigWrapper.executeTransactionAsync(erc721AddAuthorizedAddressTxId, owners[0]);
@@ -257,9 +261,9 @@ describe('AssetProxyOwner', () => {
             const log = res.logs[0] as LogWithDecodedArgs<SubmissionContractEventArgs>;
             const txId = log.args.transactionId;
 
-            return expect(
+            return expectRevertOrAlwaysFailingTransactionAsync(
                 multiSig.executeRemoveAuthorizedAddress.sendTransactionAsync(txId, { from: owners[1] }),
-            ).to.be.rejectedWith(constants.REVERT);
+            );
         });
 
         it('should throw if tx destination is not registered', async () => {
@@ -276,9 +280,9 @@ describe('AssetProxyOwner', () => {
 
             await multiSigWrapper.confirmTransactionAsync(txId, owners[1]);
 
-            return expect(
+            return expectRevertOrAlwaysFailingTransactionAsync(
                 multiSig.executeRemoveAuthorizedAddress.sendTransactionAsync(txId, { from: owners[1] }),
-            ).to.be.rejectedWith(constants.REVERT);
+            );
         });
 
         it('should throw if tx data is not for removeAuthorizedAddress', async () => {
@@ -296,9 +300,9 @@ describe('AssetProxyOwner', () => {
 
             await multiSigWrapper.confirmTransactionAsync(txId, owners[1]);
 
-            return expect(
+            return expectRevertOrAlwaysFailingTransactionAsync(
                 multiSig.executeRemoveAuthorizedAddress.sendTransactionAsync(txId, { from: owners[1] }),
-            ).to.be.rejectedWith(constants.REVERT);
+            );
         });
 
         it('should execute removeAuthorizedAddress for registered address if fully confirmed', async () => {
@@ -349,9 +353,10 @@ describe('AssetProxyOwner', () => {
             const isExecuted = tx[3];
             expect(isExecuted).to.equal(true);
 
-            return expect(
+            return expectRevertOrAlwaysFailingTransactionAsync(
                 multiSig.executeRemoveAuthorizedAddress.sendTransactionAsync(txId, { from: owners[1] }),
-            ).to.be.rejectedWith(constants.REVERT);
+            );
         });
     });
 });
+// tslint:enable:no-unnecessary-type-assertion
diff --git a/packages/contracts/test/ether_token.ts b/packages/contracts/test/ether_token.ts
index 4e52b658f..e2fc69aee 100644
--- a/packages/contracts/test/ether_token.ts
+++ b/packages/contracts/test/ether_token.ts
@@ -1,11 +1,12 @@
-import { BlockchainLifecycle, devConstants, web3Factory } from '@0xproject/dev-utils';
-import { BigNumber, promisify } from '@0xproject/utils';
+import { BlockchainLifecycle } from '@0xproject/dev-utils';
+import { BigNumber } from '@0xproject/utils';
 import { Web3Wrapper } from '@0xproject/web3-wrapper';
 import * as chai from 'chai';
 import 'make-promises-safe';
 
-import { WETH9Contract } from '../src/contract_wrappers/generated/weth9';
+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';
@@ -45,9 +46,7 @@ describe('EtherToken', () => {
             const initEthBalance = await web3Wrapper.getBalanceInWeiAsync(account);
             const ethToDeposit = initEthBalance.plus(1);
 
-            return expect(etherToken.deposit.sendTransactionAsync({ value: ethToDeposit })).to.be.rejectedWith(
-                "ender doesn't have enough funds to send tx.",
-            );
+            return expectInsufficientFundsAsync(etherToken.deposit.sendTransactionAsync({ value: ethToDeposit }));
         });
 
         it('should convert deposited Ether to wrapped Ether tokens', async () => {
@@ -76,8 +75,8 @@ describe('EtherToken', () => {
             const initEthTokenBalance = await etherToken.balanceOf.callAsync(account);
             const ethTokensToWithdraw = initEthTokenBalance.plus(1);
 
-            return expect(etherToken.withdraw.sendTransactionAsync(ethTokensToWithdraw)).to.be.rejectedWith(
-                constants.REVERT,
+            return expectRevertOrAlwaysFailingTransactionAsync(
+                etherToken.withdraw.sendTransactionAsync(ethTokensToWithdraw),
             );
         });
 
diff --git a/packages/contracts/test/exchange/core.ts b/packages/contracts/test/exchange/core.ts
index 6d62c2b86..63c2fa6c0 100644
--- a/packages/contracts/test/exchange/core.ts
+++ b/packages/contracts/test/exchange/core.ts
@@ -8,16 +8,17 @@ import { LogWithDecodedArgs } from 'ethereum-types';
 import ethUtil = require('ethereumjs-util');
 import 'make-promises-safe';
 
-import { DummyERC20TokenContract } from '../../src/contract_wrappers/generated/dummy_e_r_c20_token';
-import { DummyERC721TokenContract } from '../../src/contract_wrappers/generated/dummy_e_r_c721_token';
-import { ERC20ProxyContract } from '../../src/contract_wrappers/generated/e_r_c20_proxy';
-import { ERC721ProxyContract } from '../../src/contract_wrappers/generated/e_r_c721_proxy';
+import { DummyERC20TokenContract } from '../../src/generated_contract_wrappers/dummy_e_r_c20_token';
+import { DummyERC721TokenContract } from '../../src/generated_contract_wrappers/dummy_e_r_c721_token';
+import { ERC20ProxyContract } from '../../src/generated_contract_wrappers/e_r_c20_proxy';
+import { ERC721ProxyContract } from '../../src/generated_contract_wrappers/e_r_c721_proxy';
 import {
     CancelContractEventArgs,
     ExchangeContract,
     FillContractEventArgs,
-} from '../../src/contract_wrappers/generated/exchange';
+} from '../../src/generated_contract_wrappers/exchange';
 import { artifacts } from '../../src/utils/artifacts';
+import { expectRevertOrAlwaysFailingTransactionAsync } from '../../src/utils/assertions';
 import { chaiSetup } from '../../src/utils/chai_setup';
 import { constants } from '../../src/utils/constants';
 import { ERC20Wrapper } from '../../src/utils/erc20_wrapper';
@@ -30,7 +31,7 @@ import { provider, txDefaults, web3Wrapper } from '../../src/utils/web3_wrapper'
 chaiSetup.configure();
 const expect = chai.expect;
 const blockchainLifecycle = new BlockchainLifecycle(web3Wrapper);
-
+// tslint:disable:no-unnecessary-type-assertion
 describe('Exchange core', () => {
     let makerAddress: string;
     let owner: string;
@@ -86,7 +87,7 @@ describe('Exchange core', () => {
             artifacts.Exchange,
             provider,
             txDefaults,
-            assetProxyUtils.encodeERC20ProxyData(zrxToken.address),
+            zrxToken.address,
         );
         exchangeWrapper = new ExchangeWrapper(exchange, provider);
         await exchangeWrapper.registerAssetProxyAsync(AssetProxyId.ERC20, erc20Proxy.address, owner);
@@ -113,8 +114,8 @@ describe('Exchange core', () => {
             exchangeAddress: exchange.address,
             makerAddress,
             feeRecipientAddress,
-            makerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultMakerAssetAddress),
-            takerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultTakerAssetAddress),
+            makerAssetData: assetProxyUtils.encodeERC20AssetData(defaultMakerAssetAddress),
+            takerAssetData: assetProxyUtils.encodeERC20AssetData(defaultTakerAssetAddress),
         };
         const privateKey = constants.TESTRPC_PRIVATE_KEYS[accounts.indexOf(makerAddress)];
         orderFactory = new OrderFactory(privateKey, defaultOrderParams);
@@ -414,8 +415,8 @@ describe('Exchange core', () => {
                 makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(100), 18),
                 takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(200), 18),
             });
-            return expect(exchangeWrapper.fillOrderAsync(signedOrder, takerAddress)).to.be.rejectedWith(
-                constants.REVERT,
+            return expectRevertOrAlwaysFailingTransactionAsync(
+                exchangeWrapper.fillOrderAsync(signedOrder, takerAddress),
             );
         });
 
@@ -431,8 +432,8 @@ describe('Exchange core', () => {
             const invalidSigBuff = Buffer.concat([v, invalidR, invalidS, signatureType]);
             const invalidSigHex = `0x${invalidSigBuff.toString('hex')}`;
             signedOrder.signature = invalidSigHex;
-            return expect(exchangeWrapper.fillOrderAsync(signedOrder, takerAddress)).to.be.rejectedWith(
-                constants.REVERT,
+            return expectRevertOrAlwaysFailingTransactionAsync(
+                exchangeWrapper.fillOrderAsync(signedOrder, takerAddress),
             );
         });
 
@@ -441,8 +442,8 @@ describe('Exchange core', () => {
                 makerAssetAmount: new BigNumber(0),
             });
 
-            return expect(exchangeWrapper.fillOrderAsync(signedOrder, takerAddress)).to.be.rejectedWith(
-                constants.REVERT,
+            return expectRevertOrAlwaysFailingTransactionAsync(
+                exchangeWrapper.fillOrderAsync(signedOrder, takerAddress),
             );
         });
 
@@ -451,19 +452,19 @@ describe('Exchange core', () => {
                 takerAssetAmount: new BigNumber(0),
             });
 
-            return expect(exchangeWrapper.fillOrderAsync(signedOrder, takerAddress)).to.be.rejectedWith(
-                constants.REVERT,
+            return expectRevertOrAlwaysFailingTransactionAsync(
+                exchangeWrapper.fillOrderAsync(signedOrder, takerAddress),
             );
         });
 
         it('should throw if takerAssetFillAmount is 0', async () => {
             signedOrder = orderFactory.newSignedOrder();
 
-            return expect(
+            return expectRevertOrAlwaysFailingTransactionAsync(
                 exchangeWrapper.fillOrderAsync(signedOrder, takerAddress, {
                     takerAssetFillAmount: new BigNumber(0),
                 }),
-            ).to.be.rejectedWith(constants.REVERT);
+            );
         });
 
         it('should throw if maker erc20Balances are too low to fill order', async () => {
@@ -471,8 +472,8 @@ describe('Exchange core', () => {
                 makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(100000), 18),
             });
 
-            return expect(exchangeWrapper.fillOrderAsync(signedOrder, takerAddress)).to.be.rejectedWith(
-                constants.REVERT,
+            return expectRevertOrAlwaysFailingTransactionAsync(
+                exchangeWrapper.fillOrderAsync(signedOrder, takerAddress),
             );
         });
 
@@ -480,9 +481,8 @@ describe('Exchange core', () => {
             signedOrder = orderFactory.newSignedOrder({
                 takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(100000), 18),
             });
-
-            return expect(exchangeWrapper.fillOrderAsync(signedOrder, takerAddress)).to.be.rejectedWith(
-                constants.REVERT,
+            return expectRevertOrAlwaysFailingTransactionAsync(
+                exchangeWrapper.fillOrderAsync(signedOrder, takerAddress),
             );
         });
 
@@ -493,11 +493,8 @@ describe('Exchange core', () => {
                 }),
                 constants.AWAIT_TRANSACTION_MINED_MS,
             );
-            // HACK: `rejectWith` returns a "promise-like" type, but not an actual "Promise", so TSLint
-            // complains, even though we do need to `await` it. So we disable the TSLint error below.
-            // tslint:disable-next-line:await-promise
-            await expect(exchangeWrapper.fillOrderAsync(signedOrder, takerAddress)).to.be.rejectedWith(
-                constants.REVERT,
+            return expectRevertOrAlwaysFailingTransactionAsync(
+                exchangeWrapper.fillOrderAsync(signedOrder, takerAddress),
             );
         });
 
@@ -508,11 +505,8 @@ describe('Exchange core', () => {
                 }),
                 constants.AWAIT_TRANSACTION_MINED_MS,
             );
-            // HACK: `rejectWith` returns a "promise-like" type, but not an actual "Promise", so TSLint
-            // complains, even though we do need to `await` it. So we disable the TSLint error below.
-            // tslint:disable-next-line:await-promise
-            await expect(exchangeWrapper.fillOrderAsync(signedOrder, takerAddress)).to.be.rejectedWith(
-                constants.REVERT,
+            return expectRevertOrAlwaysFailingTransactionAsync(
+                exchangeWrapper.fillOrderAsync(signedOrder, takerAddress),
             );
         });
 
@@ -520,16 +514,16 @@ describe('Exchange core', () => {
             signedOrder = orderFactory.newSignedOrder({
                 expirationTimeSeconds: new BigNumber(Math.floor((Date.now() - 10000) / 1000)),
             });
-            return expect(exchangeWrapper.fillOrderAsync(signedOrder, takerAddress)).to.be.rejectedWith(
-                constants.REVERT,
+            return expectRevertOrAlwaysFailingTransactionAsync(
+                exchangeWrapper.fillOrderAsync(signedOrder, takerAddress),
             );
         });
 
         it('should throw if no value is filled', async () => {
             signedOrder = orderFactory.newSignedOrder();
             await exchangeWrapper.fillOrderAsync(signedOrder, takerAddress);
-            return expect(exchangeWrapper.fillOrderAsync(signedOrder, takerAddress)).to.be.rejectedWith(
-                constants.REVERT,
+            return expectRevertOrAlwaysFailingTransactionAsync(
+                exchangeWrapper.fillOrderAsync(signedOrder, takerAddress),
             );
         });
     });
@@ -541,8 +535,8 @@ describe('Exchange core', () => {
         });
 
         it('should throw if not sent by maker', async () => {
-            return expect(exchangeWrapper.cancelOrderAsync(signedOrder, takerAddress)).to.be.rejectedWith(
-                constants.REVERT,
+            return expectRevertOrAlwaysFailingTransactionAsync(
+                exchangeWrapper.cancelOrderAsync(signedOrder, takerAddress),
             );
         });
 
@@ -551,8 +545,8 @@ describe('Exchange core', () => {
                 makerAssetAmount: new BigNumber(0),
             });
 
-            return expect(exchangeWrapper.cancelOrderAsync(signedOrder, makerAddress)).to.be.rejectedWith(
-                constants.REVERT,
+            return expectRevertOrAlwaysFailingTransactionAsync(
+                exchangeWrapper.cancelOrderAsync(signedOrder, makerAddress),
             );
         });
 
@@ -561,22 +555,21 @@ describe('Exchange core', () => {
                 takerAssetAmount: new BigNumber(0),
             });
 
-            return expect(exchangeWrapper.cancelOrderAsync(signedOrder, makerAddress)).to.be.rejectedWith(
-                constants.REVERT,
+            return expectRevertOrAlwaysFailingTransactionAsync(
+                exchangeWrapper.cancelOrderAsync(signedOrder, makerAddress),
             );
         });
 
         it('should be able to cancel a full order', async () => {
             await exchangeWrapper.cancelOrderAsync(signedOrder, makerAddress);
-            return expect(
+            return expectRevertOrAlwaysFailingTransactionAsync(
                 exchangeWrapper.fillOrderAsync(signedOrder, takerAddress, {
                     takerAssetFillAmount: signedOrder.takerAssetAmount.div(2),
                 }),
-            ).to.be.rejectedWith(constants.REVERT);
+            );
         });
 
         it('should log 1 event with correct arguments', async () => {
-            const divisor = 2;
             const res = await exchangeWrapper.cancelOrderAsync(signedOrder, makerAddress);
             expect(res.logs).to.have.length(1);
 
@@ -592,8 +585,8 @@ describe('Exchange core', () => {
 
         it('should throw if already cancelled', async () => {
             await exchangeWrapper.cancelOrderAsync(signedOrder, makerAddress);
-            return expect(exchangeWrapper.cancelOrderAsync(signedOrder, makerAddress)).to.be.rejectedWith(
-                constants.REVERT,
+            return expectRevertOrAlwaysFailingTransactionAsync(
+                exchangeWrapper.cancelOrderAsync(signedOrder, makerAddress),
             );
         });
 
@@ -601,8 +594,8 @@ describe('Exchange core', () => {
             signedOrder = orderFactory.newSignedOrder({
                 expirationTimeSeconds: new BigNumber(Math.floor((Date.now() - 10000) / 1000)),
             });
-            return expect(exchangeWrapper.cancelOrderAsync(signedOrder, makerAddress)).to.be.rejectedWith(
-                constants.REVERT,
+            return expectRevertOrAlwaysFailingTransactionAsync(
+                exchangeWrapper.cancelOrderAsync(signedOrder, makerAddress),
             );
         });
 
@@ -618,11 +611,11 @@ describe('Exchange core', () => {
             });
 
             const fillTakerAssetAmount2 = new BigNumber(1);
-            return expect(
+            return expectRevertOrAlwaysFailingTransactionAsync(
                 exchangeWrapper.fillOrderAsync(signedOrder, takerAddress, {
                     takerAssetFillAmount: fillTakerAssetAmount2,
                 }),
-            ).to.be.rejectedWith(constants.REVERT);
+            );
         });
     });
 
@@ -631,16 +624,16 @@ describe('Exchange core', () => {
             const makerEpoch = new BigNumber(1);
             await exchangeWrapper.cancelOrdersUpToAsync(makerEpoch, makerAddress);
             const lesserMakerEpoch = new BigNumber(0);
-            return expect(exchangeWrapper.cancelOrdersUpToAsync(lesserMakerEpoch, makerAddress)).to.be.rejectedWith(
-                constants.REVERT,
+            return expectRevertOrAlwaysFailingTransactionAsync(
+                exchangeWrapper.cancelOrdersUpToAsync(lesserMakerEpoch, makerAddress),
             );
         });
 
         it('should fail to set makerEpoch equal to existing makerEpoch', async () => {
             const makerEpoch = new BigNumber(1);
             await exchangeWrapper.cancelOrdersUpToAsync(makerEpoch, makerAddress);
-            return expect(exchangeWrapper.cancelOrdersUpToAsync(makerEpoch, makerAddress)).to.be.rejectedWith(
-                constants.REVERT,
+            return expectRevertOrAlwaysFailingTransactionAsync(
+                exchangeWrapper.cancelOrdersUpToAsync(makerEpoch, makerAddress),
             );
         });
 
@@ -674,7 +667,12 @@ describe('Exchange core', () => {
                     salt: new BigNumber(3),
                 }),
             ];
-            await exchangeWrapper.batchFillOrdersNoThrowAsync(signedOrders, takerAddress);
+            await exchangeWrapper.batchFillOrdersNoThrowAsync(signedOrders, takerAddress, {
+                // HACK(albrow): We need to hardcode the gas estimate here because
+                // the Geth gas estimator doesn't work with the way we use
+                // delegatecall and swallow errors.
+                gas: 490000,
+            });
 
             const newBalances = await erc20Wrapper.getBalancesAsync();
             const fillMakerAssetAmount = signedOrders[2].makerAssetAmount.add(signedOrders[3].makerAssetAmount);
@@ -713,8 +711,8 @@ describe('Exchange core', () => {
             signedOrder = orderFactory.newSignedOrder({
                 makerAssetAmount: new BigNumber(1),
                 takerAssetAmount: new BigNumber(1),
-                makerAssetData: assetProxyUtils.encodeERC721ProxyData(erc721Token.address, makerAssetId),
-                takerAssetData: assetProxyUtils.encodeERC721ProxyData(erc721Token.address, takerAssetId),
+                makerAssetData: assetProxyUtils.encodeERC721AssetData(erc721Token.address, makerAssetId),
+                takerAssetData: assetProxyUtils.encodeERC721AssetData(erc721Token.address, takerAssetId),
             });
             // Verify pre-conditions
             const initialOwnerMakerAsset = await erc721Token.ownerOf.callAsync(makerAssetId);
@@ -723,6 +721,7 @@ describe('Exchange core', () => {
             expect(initialOwnerTakerAsset).to.be.bignumber.equal(takerAddress);
             // Call Exchange
             const takerAssetFillAmount = signedOrder.takerAssetAmount;
+            // tslint:disable-next-line:no-unused-variable
             const res = await exchangeWrapper.fillOrderAsync(signedOrder, takerAddress, { takerAssetFillAmount });
             // Verify post-conditions
             const newOwnerMakerAsset = await erc721Token.ownerOf.callAsync(makerAssetId);
@@ -738,8 +737,8 @@ describe('Exchange core', () => {
             signedOrder = orderFactory.newSignedOrder({
                 makerAssetAmount: new BigNumber(1),
                 takerAssetAmount: new BigNumber(1),
-                makerAssetData: assetProxyUtils.encodeERC721ProxyData(erc721Token.address, makerAssetId),
-                takerAssetData: assetProxyUtils.encodeERC721ProxyData(erc721Token.address, takerAssetId),
+                makerAssetData: assetProxyUtils.encodeERC721AssetData(erc721Token.address, makerAssetId),
+                takerAssetData: assetProxyUtils.encodeERC721AssetData(erc721Token.address, takerAssetId),
             });
             // Verify pre-conditions
             const initialOwnerMakerAsset = await erc721Token.ownerOf.callAsync(makerAssetId);
@@ -748,9 +747,9 @@ describe('Exchange core', () => {
             expect(initialOwnerTakerAsset).to.be.bignumber.equal(takerAddress);
             // Call Exchange
             const takerAssetFillAmount = signedOrder.takerAssetAmount;
-            return expect(
+            return expectRevertOrAlwaysFailingTransactionAsync(
                 exchangeWrapper.fillOrderAsync(signedOrder, takerAddress, { takerAssetFillAmount }),
-            ).to.be.rejectedWith(constants.REVERT);
+            );
         });
 
         it('should throw when taker does not own the token with id takerAssetId', async () => {
@@ -760,8 +759,8 @@ describe('Exchange core', () => {
             signedOrder = orderFactory.newSignedOrder({
                 makerAssetAmount: new BigNumber(1),
                 takerAssetAmount: new BigNumber(1),
-                makerAssetData: assetProxyUtils.encodeERC721ProxyData(erc721Token.address, makerAssetId),
-                takerAssetData: assetProxyUtils.encodeERC721ProxyData(erc721Token.address, takerAssetId),
+                makerAssetData: assetProxyUtils.encodeERC721AssetData(erc721Token.address, makerAssetId),
+                takerAssetData: assetProxyUtils.encodeERC721AssetData(erc721Token.address, takerAssetId),
             });
             // Verify pre-conditions
             const initialOwnerMakerAsset = await erc721Token.ownerOf.callAsync(makerAssetId);
@@ -770,9 +769,9 @@ describe('Exchange core', () => {
             expect(initialOwnerTakerAsset).to.be.bignumber.not.equal(takerAddress);
             // Call Exchange
             const takerAssetFillAmount = signedOrder.takerAssetAmount;
-            return expect(
+            return expectRevertOrAlwaysFailingTransactionAsync(
                 exchangeWrapper.fillOrderAsync(signedOrder, takerAddress, { takerAssetFillAmount }),
-            ).to.be.rejectedWith(constants.REVERT);
+            );
         });
 
         it('should throw when makerAssetAmount is greater than 1', async () => {
@@ -782,8 +781,8 @@ describe('Exchange core', () => {
             signedOrder = orderFactory.newSignedOrder({
                 makerAssetAmount: new BigNumber(2),
                 takerAssetAmount: new BigNumber(1),
-                makerAssetData: assetProxyUtils.encodeERC721ProxyData(erc721Token.address, makerAssetId),
-                takerAssetData: assetProxyUtils.encodeERC721ProxyData(erc721Token.address, takerAssetId),
+                makerAssetData: assetProxyUtils.encodeERC721AssetData(erc721Token.address, makerAssetId),
+                takerAssetData: assetProxyUtils.encodeERC721AssetData(erc721Token.address, takerAssetId),
             });
             // Verify pre-conditions
             const initialOwnerMakerAsset = await erc721Token.ownerOf.callAsync(makerAssetId);
@@ -792,9 +791,9 @@ describe('Exchange core', () => {
             expect(initialOwnerTakerAsset).to.be.bignumber.equal(takerAddress);
             // Call Exchange
             const takerAssetFillAmount = signedOrder.takerAssetAmount;
-            return expect(
+            return expectRevertOrAlwaysFailingTransactionAsync(
                 exchangeWrapper.fillOrderAsync(signedOrder, takerAddress, { takerAssetFillAmount }),
-            ).to.be.rejectedWith(constants.REVERT);
+            );
         });
 
         it('should throw when takerAssetAmount is greater than 1', async () => {
@@ -804,8 +803,8 @@ describe('Exchange core', () => {
             signedOrder = orderFactory.newSignedOrder({
                 makerAssetAmount: new BigNumber(1),
                 takerAssetAmount: new BigNumber(500),
-                makerAssetData: assetProxyUtils.encodeERC721ProxyData(erc721Token.address, makerAssetId),
-                takerAssetData: assetProxyUtils.encodeERC721ProxyData(erc721Token.address, takerAssetId),
+                makerAssetData: assetProxyUtils.encodeERC721AssetData(erc721Token.address, makerAssetId),
+                takerAssetData: assetProxyUtils.encodeERC721AssetData(erc721Token.address, takerAssetId),
             });
             // Verify pre-conditions
             const initialOwnerMakerAsset = await erc721Token.ownerOf.callAsync(makerAssetId);
@@ -814,9 +813,9 @@ describe('Exchange core', () => {
             expect(initialOwnerTakerAsset).to.be.bignumber.equal(takerAddress);
             // Call Exchange
             const takerAssetFillAmount = signedOrder.takerAssetAmount;
-            return expect(
+            return expectRevertOrAlwaysFailingTransactionAsync(
                 exchangeWrapper.fillOrderAsync(signedOrder, takerAddress, { takerAssetFillAmount }),
-            ).to.be.rejectedWith(constants.REVERT);
+            );
         });
 
         it('should throw on partial fill', async () => {
@@ -826,8 +825,8 @@ describe('Exchange core', () => {
             signedOrder = orderFactory.newSignedOrder({
                 makerAssetAmount: new BigNumber(1),
                 takerAssetAmount: new BigNumber(0),
-                makerAssetData: assetProxyUtils.encodeERC721ProxyData(erc721Token.address, makerAssetId),
-                takerAssetData: assetProxyUtils.encodeERC721ProxyData(erc721Token.address, takerAssetId),
+                makerAssetData: assetProxyUtils.encodeERC721AssetData(erc721Token.address, makerAssetId),
+                takerAssetData: assetProxyUtils.encodeERC721AssetData(erc721Token.address, takerAssetId),
             });
             // Verify pre-conditions
             const initialOwnerMakerAsset = await erc721Token.ownerOf.callAsync(makerAssetId);
@@ -836,9 +835,9 @@ describe('Exchange core', () => {
             expect(initialOwnerTakerAsset).to.be.bignumber.equal(takerAddress);
             // Call Exchange
             const takerAssetFillAmount = signedOrder.takerAssetAmount;
-            return expect(
+            return expectRevertOrAlwaysFailingTransactionAsync(
                 exchangeWrapper.fillOrderAsync(signedOrder, takerAddress, { takerAssetFillAmount }),
-            ).to.be.rejectedWith(constants.REVERT);
+            );
         });
 
         it('should successfully fill order when makerAsset is ERC721 and takerAsset is ERC20', async () => {
@@ -847,8 +846,8 @@ describe('Exchange core', () => {
             signedOrder = orderFactory.newSignedOrder({
                 makerAssetAmount: new BigNumber(1),
                 takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(100), 18),
-                makerAssetData: assetProxyUtils.encodeERC721ProxyData(erc721Token.address, makerAssetId),
-                takerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultTakerAssetAddress),
+                makerAssetData: assetProxyUtils.encodeERC721AssetData(erc721Token.address, makerAssetId),
+                takerAssetData: assetProxyUtils.encodeERC20AssetData(defaultTakerAssetAddress),
             });
             // Verify pre-conditions
             const initialOwnerMakerAsset = await erc721Token.ownerOf.callAsync(makerAssetId);
@@ -887,8 +886,8 @@ describe('Exchange core', () => {
             signedOrder = orderFactory.newSignedOrder({
                 takerAssetAmount: new BigNumber(1),
                 makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(100), 18),
-                takerAssetData: assetProxyUtils.encodeERC721ProxyData(erc721Token.address, takerAssetId),
-                makerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultMakerAssetAddress),
+                takerAssetData: assetProxyUtils.encodeERC721AssetData(erc721Token.address, takerAssetId),
+                makerAssetData: assetProxyUtils.encodeERC20AssetData(defaultMakerAssetAddress),
             });
             // Verify pre-conditions
             const initialOwnerTakerAsset = await erc721Token.ownerOf.callAsync(takerAssetId);
@@ -921,4 +920,6 @@ describe('Exchange core', () => {
             );
         });
     });
-}); // tslint:disable-line:max-file-line-count
+});
+// tslint:disable:max-file-line-count
+// tslint:enable:no-unnecessary-type-assertion
diff --git a/packages/contracts/test/exchange/dispatcher.ts b/packages/contracts/test/exchange/dispatcher.ts
index 8bc66e3cf..abbfd7ac7 100644
--- a/packages/contracts/test/exchange/dispatcher.ts
+++ b/packages/contracts/test/exchange/dispatcher.ts
@@ -3,13 +3,13 @@ import { assetProxyUtils } from '@0xproject/order-utils';
 import { AssetProxyId } from '@0xproject/types';
 import { BigNumber } from '@0xproject/utils';
 import * as chai from 'chai';
-import * as Web3 from 'web3';
 
-import { DummyERC20TokenContract } from '../../src/contract_wrappers/generated/dummy_e_r_c20_token';
-import { ERC20ProxyContract } from '../../src/contract_wrappers/generated/e_r_c20_proxy';
-import { ERC721ProxyContract } from '../../src/contract_wrappers/generated/e_r_c721_proxy';
-import { TestAssetProxyDispatcherContract } from '../../src/contract_wrappers/generated/test_asset_proxy_dispatcher';
+import { DummyERC20TokenContract } from '../../src/generated_contract_wrappers/dummy_e_r_c20_token';
+import { ERC20ProxyContract } from '../../src/generated_contract_wrappers/e_r_c20_proxy';
+import { ERC721ProxyContract } from '../../src/generated_contract_wrappers/e_r_c721_proxy';
+import { TestAssetProxyDispatcherContract } from '../../src/generated_contract_wrappers/test_asset_proxy_dispatcher';
 import { artifacts } from '../../src/utils/artifacts';
+import { expectRevertOrAlwaysFailingTransactionAsync } from '../../src/utils/assertions';
 import { chaiSetup } from '../../src/utils/chai_setup';
 import { constants } from '../../src/utils/constants';
 import { ERC20Wrapper } from '../../src/utils/erc20_wrapper';
@@ -23,7 +23,6 @@ const blockchainLifecycle = new BlockchainLifecycle(web3Wrapper);
 describe('AssetProxyDispatcher', () => {
     let owner: string;
     let notOwner: string;
-    let notAuthorized: string;
     let makerAddress: string;
     let takerAddress: string;
 
@@ -45,7 +44,6 @@ describe('AssetProxyDispatcher', () => {
         // Setup accounts & addresses
         const accounts = await web3Wrapper.getAvailableAddressesAsync();
         const usedAddresses = ([owner, notOwner, makerAddress, takerAddress] = accounts);
-        notAuthorized = notOwner;
 
         erc20Wrapper = new ERC20Wrapper(provider, usedAddresses, owner);
         erc721Wrapper = new ERC721Wrapper(provider, usedAddresses, owner);
@@ -177,14 +175,14 @@ describe('AssetProxyDispatcher', () => {
             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 expect(
+            return expectRevertOrAlwaysFailingTransactionAsync(
                 assetProxyDispatcher.registerAssetProxy.sendTransactionAsync(
                     AssetProxyId.ERC20,
                     erc20Proxy.address,
                     constants.NULL_ADDRESS,
                     { from: owner },
                 ),
-            ).to.be.rejectedWith(constants.REVERT);
+            );
         });
 
         it('should be able to reset proxy address to NULL', async () => {
@@ -218,26 +216,26 @@ describe('AssetProxyDispatcher', () => {
 
         it('should throw if requesting address is not owner', async () => {
             const prevProxyAddress = constants.NULL_ADDRESS;
-            return expect(
+            return expectRevertOrAlwaysFailingTransactionAsync(
                 assetProxyDispatcher.registerAssetProxy.sendTransactionAsync(
                     AssetProxyId.ERC20,
                     erc20Proxy.address,
                     prevProxyAddress,
                     { from: notOwner },
                 ),
-            ).to.be.rejectedWith(constants.REVERT);
+            );
         });
 
         it('should throw if attempting to register a proxy to the incorrect id', async () => {
             const prevProxyAddress = constants.NULL_ADDRESS;
-            return expect(
+            return expectRevertOrAlwaysFailingTransactionAsync(
                 assetProxyDispatcher.registerAssetProxy.sendTransactionAsync(
                     AssetProxyId.ERC721,
                     erc20Proxy.address,
                     prevProxyAddress,
                     { from: owner },
                 ),
-            ).to.be.rejectedWith(constants.REVERT);
+            );
         });
     });
 
@@ -277,13 +275,15 @@ describe('AssetProxyDispatcher', () => {
                 constants.AWAIT_TRANSACTION_MINED_MS,
             );
             // Construct metadata for ERC20 proxy
-            const encodedProxyMetadata = assetProxyUtils.encodeERC20ProxyData(zrxToken.address);
+            const encodedAssetData = assetProxyUtils.encodeERC20AssetData(zrxToken.address);
+            const encodedAssetDataWithoutProxyId = encodedAssetData.slice(0, -2);
             // Perform a transfer from makerAddress to takerAddress
             const erc20Balances = await erc20Wrapper.getBalancesAsync();
             const amount = new BigNumber(10);
             await web3Wrapper.awaitTransactionSuccessAsync(
                 await assetProxyDispatcher.publicDispatchTransferFrom.sendTransactionAsync(
-                    encodedProxyMetadata,
+                    encodedAssetDataWithoutProxyId,
+                    AssetProxyId.ERC20,
                     makerAddress,
                     takerAddress,
                     amount,
@@ -303,19 +303,20 @@ describe('AssetProxyDispatcher', () => {
 
         it('should throw if dispatching to unregistered proxy', async () => {
             // Construct metadata for ERC20 proxy
-            const encodedProxyMetadata = assetProxyUtils.encodeERC20ProxyData(zrxToken.address);
+            const encodedAssetData = assetProxyUtils.encodeERC20AssetData(zrxToken.address);
+            const encodedAssetDataWithoutProxyId = encodedAssetData.slice(0, -2);
             // Perform a transfer from makerAddress to takerAddress
-            const erc20Balances = await erc20Wrapper.getBalancesAsync();
             const amount = new BigNumber(10);
-            return expect(
+            return expectRevertOrAlwaysFailingTransactionAsync(
                 assetProxyDispatcher.publicDispatchTransferFrom.sendTransactionAsync(
-                    encodedProxyMetadata,
+                    encodedAssetDataWithoutProxyId,
+                    AssetProxyId.ERC20,
                     makerAddress,
                     takerAddress,
                     amount,
                     { from: owner },
                 ),
-            ).to.be.rejectedWith(constants.REVERT);
+            );
         });
     });
 });
diff --git a/packages/contracts/test/exchange/libs.ts b/packages/contracts/test/exchange/libs.ts
index ac9020bce..c08001198 100644
--- a/packages/contracts/test/exchange/libs.ts
+++ b/packages/contracts/test/exchange/libs.ts
@@ -3,9 +3,8 @@ import { assetProxyUtils, EIP712Utils, orderHashUtils } from '@0xproject/order-u
 import { SignedOrder } from '@0xproject/types';
 import { BigNumber } from '@0xproject/utils';
 import * as chai from 'chai';
-import ethUtil = require('ethereumjs-util');
 
-import { TestLibsContract } from '../../src/contract_wrappers/generated/test_libs';
+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';
@@ -39,8 +38,8 @@ describe('Exchange libs', () => {
             exchangeAddress: libs.address,
             makerAddress,
             feeRecipientAddress: addressUtils.generatePseudoRandomAddress(),
-            makerAssetData: assetProxyUtils.encodeERC20ProxyData(addressUtils.generatePseudoRandomAddress()),
-            takerAssetData: assetProxyUtils.encodeERC20ProxyData(addressUtils.generatePseudoRandomAddress()),
+            makerAssetData: assetProxyUtils.encodeERC20AssetData(addressUtils.generatePseudoRandomAddress()),
+            takerAssetData: assetProxyUtils.encodeERC20AssetData(addressUtils.generatePseudoRandomAddress()),
         };
         const privateKey = constants.TESTRPC_PRIVATE_KEYS[accounts.indexOf(makerAddress)];
         orderFactory = new OrderFactory(privateKey, defaultOrderParams);
diff --git a/packages/contracts/test/exchange/match_orders.ts b/packages/contracts/test/exchange/match_orders.ts
index 24ee794bc..b8dca04fd 100644
--- a/packages/contracts/test/exchange/match_orders.ts
+++ b/packages/contracts/test/exchange/match_orders.ts
@@ -1,23 +1,18 @@
 import { BlockchainLifecycle } from '@0xproject/dev-utils';
-import { assetProxyUtils, crypto } from '@0xproject/order-utils';
-import { AssetProxyId, SignedOrder } from '@0xproject/types';
+import { assetProxyUtils } from '@0xproject/order-utils';
+import { AssetProxyId } from '@0xproject/types';
 import { BigNumber } from '@0xproject/utils';
 import { Web3Wrapper } from '@0xproject/web3-wrapper';
 import * as chai from 'chai';
-import { LogWithDecodedArgs } from 'ethereum-types';
-import ethUtil = require('ethereumjs-util');
 import * as _ from 'lodash';
 
-import { DummyERC20TokenContract } from '../../src/contract_wrappers/generated/dummy_e_r_c20_token';
-import { DummyERC721TokenContract } from '../../src/contract_wrappers/generated/dummy_e_r_c721_token';
-import { ERC20ProxyContract } from '../../src/contract_wrappers/generated/e_r_c20_proxy';
-import { ERC721ProxyContract } from '../../src/contract_wrappers/generated/e_r_c721_proxy';
-import {
-    CancelContractEventArgs,
-    ExchangeContract,
-    FillContractEventArgs,
-} from '../../src/contract_wrappers/generated/exchange';
+import { DummyERC20TokenContract } from '../../src/generated_contract_wrappers/dummy_e_r_c20_token';
+import { DummyERC721TokenContract } from '../../src/generated_contract_wrappers/dummy_e_r_c721_token';
+import { ERC20ProxyContract } from '../../src/generated_contract_wrappers/e_r_c20_proxy';
+import { ERC721ProxyContract } from '../../src/generated_contract_wrappers/e_r_c721_proxy';
+import { ExchangeContract } from '../../src/generated_contract_wrappers/exchange';
 import { artifacts } from '../../src/utils/artifacts';
+import { expectRevertOrAlwaysFailingTransactionAsync } from '../../src/utils/assertions';
 import { chaiSetup } from '../../src/utils/chai_setup';
 import { constants } from '../../src/utils/constants';
 import { ERC20Wrapper } from '../../src/utils/erc20_wrapper';
@@ -25,13 +20,7 @@ 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 {
-    ContractName,
-    ERC20BalancesByOwner,
-    ERC721TokenIdsByOwner,
-    OrderInfo,
-    OrderStatus,
-} from '../../src/utils/types';
+import { ERC20BalancesByOwner, ERC721TokenIdsByOwner, OrderInfo, OrderStatus } from '../../src/utils/types';
 import { provider, txDefaults, web3Wrapper } from '../../src/utils/web3_wrapper';
 
 chaiSetup.configure();
@@ -64,7 +53,6 @@ describe('matchOrders', () => {
 
     let erc721LeftMakerAssetIds: BigNumber[];
     let erc721RightMakerAssetIds: BigNumber[];
-    let erc721TakerAssetIds: BigNumber[];
 
     let defaultERC20MakerAssetAddress: string;
     let defaultERC20TakerAssetAddress: string;
@@ -103,13 +91,12 @@ describe('matchOrders', () => {
         const erc721Balances = await erc721Wrapper.getBalancesAsync();
         erc721LeftMakerAssetIds = erc721Balances[makerAddressLeft][erc721Token.address];
         erc721RightMakerAssetIds = erc721Balances[makerAddressRight][erc721Token.address];
-        erc721TakerAssetIds = erc721Balances[takerAddress][erc721Token.address];
         // Depoy exchange
         exchange = await ExchangeContract.deployFrom0xArtifactAsync(
             artifacts.Exchange,
             provider,
             txDefaults,
-            assetProxyUtils.encodeERC20ProxyData(zrxToken.address),
+            zrxToken.address,
         );
         exchangeWrapper = new ExchangeWrapper(exchange, provider);
         await exchangeWrapper.registerAssetProxyAsync(AssetProxyId.ERC20, erc20Proxy.address, owner);
@@ -135,8 +122,8 @@ describe('matchOrders', () => {
         const defaultOrderParams = {
             ...constants.STATIC_ORDER_PARAMS,
             exchangeAddress: exchange.address,
-            makerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20MakerAssetAddress),
-            takerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20TakerAssetAddress),
+            makerAssetData: assetProxyUtils.encodeERC20AssetData(defaultERC20MakerAssetAddress),
+            takerAssetData: assetProxyUtils.encodeERC20AssetData(defaultERC20TakerAssetAddress),
         };
         const privateKeyLeft = constants.TESTRPC_PRIVATE_KEYS[accounts.indexOf(makerAddressLeft)];
         orderFactoryLeft = new OrderFactory(privateKeyLeft, defaultOrderParams);
@@ -161,16 +148,14 @@ describe('matchOrders', () => {
             // Create orders to match
             const signedOrderLeft = orderFactoryLeft.newSignedOrder({
                 makerAddress: makerAddressLeft,
-                makerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20MakerAssetAddress),
-                takerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20TakerAssetAddress),
                 makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(5), 18),
                 takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(10), 18),
                 feeRecipientAddress: feeRecipientAddressLeft,
             });
             const signedOrderRight = orderFactoryRight.newSignedOrder({
                 makerAddress: makerAddressRight,
-                makerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20TakerAssetAddress),
-                takerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20MakerAssetAddress),
+                makerAssetData: assetProxyUtils.encodeERC20AssetData(defaultERC20TakerAssetAddress),
+                takerAssetData: assetProxyUtils.encodeERC20AssetData(defaultERC20MakerAssetAddress),
                 makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(10), 18),
                 takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(2), 18),
                 feeRecipientAddress: feeRecipientAddressRight,
@@ -195,16 +180,14 @@ describe('matchOrders', () => {
             // Create orders to match
             const signedOrderLeft = orderFactoryLeft.newSignedOrder({
                 makerAddress: makerAddressLeft,
-                makerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20MakerAssetAddress),
-                takerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20TakerAssetAddress),
                 makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(5), 18),
                 takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(10), 18),
                 feeRecipientAddress: feeRecipientAddressLeft,
             });
             const signedOrderRight = orderFactoryRight.newSignedOrder({
                 makerAddress: makerAddressRight,
-                makerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20TakerAssetAddress),
-                takerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20MakerAssetAddress),
+                makerAssetData: assetProxyUtils.encodeERC20AssetData(defaultERC20TakerAssetAddress),
+                takerAssetData: assetProxyUtils.encodeERC20AssetData(defaultERC20MakerAssetAddress),
                 makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(10), 18),
                 takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(5), 18),
                 feeRecipientAddress: feeRecipientAddressRight,
@@ -240,16 +223,14 @@ describe('matchOrders', () => {
             // Create orders to match
             const signedOrderLeft = orderFactoryLeft.newSignedOrder({
                 makerAddress: makerAddressLeft,
-                makerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20MakerAssetAddress),
-                takerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20TakerAssetAddress),
                 makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(5), 18),
                 takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(10), 18),
                 feeRecipientAddress: feeRecipientAddressLeft,
             });
             const signedOrderRight = orderFactoryRight.newSignedOrder({
                 makerAddress: makerAddressRight,
-                makerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20TakerAssetAddress),
-                takerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20MakerAssetAddress),
+                makerAssetData: assetProxyUtils.encodeERC20AssetData(defaultERC20TakerAssetAddress),
+                takerAssetData: assetProxyUtils.encodeERC20AssetData(defaultERC20MakerAssetAddress),
                 makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(20), 18),
                 takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(4), 18),
                 feeRecipientAddress: feeRecipientAddressRight,
@@ -274,16 +255,14 @@ describe('matchOrders', () => {
             // Create orders to match
             const signedOrderLeft = orderFactoryLeft.newSignedOrder({
                 makerAddress: makerAddressLeft,
-                makerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20MakerAssetAddress),
-                takerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20TakerAssetAddress),
                 makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(50), 18),
                 takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(100), 18),
                 feeRecipientAddress: feeRecipientAddressLeft,
             });
             const signedOrderRight = orderFactoryRight.newSignedOrder({
                 makerAddress: makerAddressRight,
-                makerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20TakerAssetAddress),
-                takerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20MakerAssetAddress),
+                makerAssetData: assetProxyUtils.encodeERC20AssetData(defaultERC20TakerAssetAddress),
+                takerAssetData: assetProxyUtils.encodeERC20AssetData(defaultERC20MakerAssetAddress),
                 makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(10), 18),
                 takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(2), 18),
                 feeRecipientAddress: feeRecipientAddressRight,
@@ -308,16 +287,14 @@ describe('matchOrders', () => {
             // Create orders to match
             const signedOrderLeft = orderFactoryLeft.newSignedOrder({
                 makerAddress: makerAddressLeft,
-                makerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20MakerAssetAddress),
-                takerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20TakerAssetAddress),
                 makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(50), 18),
                 takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(100), 18),
                 feeRecipientAddress: feeRecipientAddressLeft,
             });
             const signedOrderRight = orderFactoryRight.newSignedOrder({
                 makerAddress: makerAddressRight,
-                makerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20TakerAssetAddress),
-                takerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20MakerAssetAddress),
+                makerAssetData: assetProxyUtils.encodeERC20AssetData(defaultERC20TakerAssetAddress),
+                takerAssetData: assetProxyUtils.encodeERC20AssetData(defaultERC20MakerAssetAddress),
                 makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(10), 18),
                 takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(2), 18),
                 feeRecipientAddress: feeRecipientAddressRight,
@@ -347,8 +324,8 @@ describe('matchOrders', () => {
             //       branch in the contract twice for this test.
             const signedOrderRight2 = orderFactoryRight.newSignedOrder({
                 makerAddress: makerAddressRight,
-                makerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20TakerAssetAddress),
-                takerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20MakerAssetAddress),
+                makerAssetData: assetProxyUtils.encodeERC20AssetData(defaultERC20TakerAssetAddress),
+                takerAssetData: assetProxyUtils.encodeERC20AssetData(defaultERC20MakerAssetAddress),
                 makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(100), 18),
                 takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(50), 18),
                 feeRecipientAddress: feeRecipientAddressRight,
@@ -377,8 +354,6 @@ describe('matchOrders', () => {
             // Create orders to match
             const signedOrderLeft = orderFactoryLeft.newSignedOrder({
                 makerAddress: makerAddressLeft,
-                makerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20MakerAssetAddress),
-                takerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20TakerAssetAddress),
                 makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(10), 18),
                 takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(2), 18),
                 feeRecipientAddress: feeRecipientAddressLeft,
@@ -386,8 +361,8 @@ describe('matchOrders', () => {
 
             const signedOrderRight = orderFactoryRight.newSignedOrder({
                 makerAddress: makerAddressRight,
-                makerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20TakerAssetAddress),
-                takerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20MakerAssetAddress),
+                makerAssetData: assetProxyUtils.encodeERC20AssetData(defaultERC20TakerAssetAddress),
+                takerAssetData: assetProxyUtils.encodeERC20AssetData(defaultERC20MakerAssetAddress),
                 makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(50), 18),
                 takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(100), 18),
                 feeRecipientAddress: feeRecipientAddressRight,
@@ -417,8 +392,6 @@ describe('matchOrders', () => {
             //       branch in the contract twice for this test.
             const signedOrderLeft2 = orderFactoryLeft.newSignedOrder({
                 makerAddress: makerAddressLeft,
-                makerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20MakerAssetAddress),
-                takerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20TakerAssetAddress),
                 makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(100), 18),
                 takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(50), 18),
                 feeRecipientAddress: feeRecipientAddressLeft,
@@ -450,16 +423,14 @@ describe('matchOrders', () => {
             const feeRecipientAddress = feeRecipientAddressLeft;
             const signedOrderLeft = orderFactoryLeft.newSignedOrder({
                 makerAddress: makerAddressLeft,
-                makerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20MakerAssetAddress),
-                takerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20TakerAssetAddress),
                 makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(5), 18),
                 takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(10), 18),
                 feeRecipientAddress,
             });
             const signedOrderRight = orderFactoryRight.newSignedOrder({
                 makerAddress: makerAddressRight,
-                makerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20TakerAssetAddress),
-                takerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20MakerAssetAddress),
+                makerAssetData: assetProxyUtils.encodeERC20AssetData(defaultERC20TakerAssetAddress),
+                takerAssetData: assetProxyUtils.encodeERC20AssetData(defaultERC20MakerAssetAddress),
                 makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(10), 18),
                 takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(2), 18),
                 feeRecipientAddress,
@@ -478,16 +449,14 @@ describe('matchOrders', () => {
             // Create orders to match
             const signedOrderLeft = orderFactoryLeft.newSignedOrder({
                 makerAddress: makerAddressLeft,
-                makerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20MakerAssetAddress),
-                takerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20TakerAssetAddress),
                 makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(5), 18),
                 takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(10), 18),
                 feeRecipientAddress: feeRecipientAddressLeft,
             });
             const signedOrderRight = orderFactoryRight.newSignedOrder({
                 makerAddress: makerAddressRight,
-                makerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20TakerAssetAddress),
-                takerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20MakerAssetAddress),
+                makerAssetData: assetProxyUtils.encodeERC20AssetData(defaultERC20TakerAssetAddress),
+                takerAssetData: assetProxyUtils.encodeERC20AssetData(defaultERC20MakerAssetAddress),
                 makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(10), 18),
                 takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(2), 18),
                 feeRecipientAddress: feeRecipientAddressRight,
@@ -507,16 +476,14 @@ describe('matchOrders', () => {
             // Create orders to match
             const signedOrderLeft = orderFactoryLeft.newSignedOrder({
                 makerAddress: makerAddressLeft,
-                makerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20MakerAssetAddress),
-                takerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20TakerAssetAddress),
                 makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(5), 18),
                 takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(10), 18),
                 feeRecipientAddress: feeRecipientAddressLeft,
             });
             const signedOrderRight = orderFactoryRight.newSignedOrder({
                 makerAddress: makerAddressRight,
-                makerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20TakerAssetAddress),
-                takerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20MakerAssetAddress),
+                makerAssetData: assetProxyUtils.encodeERC20AssetData(defaultERC20TakerAssetAddress),
+                takerAssetData: assetProxyUtils.encodeERC20AssetData(defaultERC20MakerAssetAddress),
                 makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(10), 18),
                 takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(2), 18),
                 feeRecipientAddress: feeRecipientAddressRight,
@@ -536,16 +503,14 @@ describe('matchOrders', () => {
             // Create orders to match
             const signedOrderLeft = orderFactoryLeft.newSignedOrder({
                 makerAddress: makerAddressLeft,
-                makerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20MakerAssetAddress),
-                takerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20TakerAssetAddress),
                 makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(5), 18),
                 takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(10), 18),
                 feeRecipientAddress: feeRecipientAddressLeft,
             });
             const signedOrderRight = orderFactoryRight.newSignedOrder({
                 makerAddress: makerAddressRight,
-                makerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20TakerAssetAddress),
-                takerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20MakerAssetAddress),
+                makerAssetData: assetProxyUtils.encodeERC20AssetData(defaultERC20TakerAssetAddress),
+                takerAssetData: assetProxyUtils.encodeERC20AssetData(defaultERC20MakerAssetAddress),
                 makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(10), 18),
                 takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(2), 18),
                 feeRecipientAddress: feeRecipientAddressRight,
@@ -565,16 +530,14 @@ describe('matchOrders', () => {
             // Create orders to match
             const signedOrderLeft = orderFactoryLeft.newSignedOrder({
                 makerAddress: makerAddressLeft,
-                makerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20MakerAssetAddress),
-                takerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20TakerAssetAddress),
                 makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(5), 18),
                 takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(10), 18),
                 feeRecipientAddress: feeRecipientAddressLeft,
             });
             const signedOrderRight = orderFactoryRight.newSignedOrder({
                 makerAddress: makerAddressRight,
-                makerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20TakerAssetAddress),
-                takerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20MakerAssetAddress),
+                makerAssetData: assetProxyUtils.encodeERC20AssetData(defaultERC20TakerAssetAddress),
+                takerAssetData: assetProxyUtils.encodeERC20AssetData(defaultERC20MakerAssetAddress),
                 makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(10), 18),
                 takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(2), 18),
                 feeRecipientAddress: feeRecipientAddressRight,
@@ -594,16 +557,14 @@ describe('matchOrders', () => {
             // Create orders to match
             const signedOrderLeft = orderFactoryLeft.newSignedOrder({
                 makerAddress: makerAddressLeft,
-                makerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20MakerAssetAddress),
-                takerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20TakerAssetAddress),
                 makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(5), 18),
                 takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(10), 18),
                 feeRecipientAddress: makerAddressLeft,
             });
             const signedOrderRight = orderFactoryRight.newSignedOrder({
                 makerAddress: makerAddressRight,
-                makerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20TakerAssetAddress),
-                takerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20MakerAssetAddress),
+                makerAssetData: assetProxyUtils.encodeERC20AssetData(defaultERC20TakerAssetAddress),
+                takerAssetData: assetProxyUtils.encodeERC20AssetData(defaultERC20MakerAssetAddress),
                 makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(10), 18),
                 takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(2), 18),
                 feeRecipientAddress: makerAddressRight,
@@ -622,16 +583,14 @@ describe('matchOrders', () => {
             // Create orders to match
             const signedOrderLeft = orderFactoryLeft.newSignedOrder({
                 makerAddress: makerAddressLeft,
-                makerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20MakerAssetAddress),
-                takerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20TakerAssetAddress),
                 makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(5), 18),
                 takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(10), 18),
                 feeRecipientAddress: feeRecipientAddressLeft,
             });
             const signedOrderRight = orderFactoryRight.newSignedOrder({
                 makerAddress: makerAddressRight,
-                makerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20TakerAssetAddress),
-                takerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20MakerAssetAddress),
+                makerAssetData: assetProxyUtils.encodeERC20AssetData(defaultERC20TakerAssetAddress),
+                takerAssetData: assetProxyUtils.encodeERC20AssetData(defaultERC20MakerAssetAddress),
                 makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(10), 18),
                 takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(2), 18),
                 feeRecipientAddress: feeRecipientAddressRight,
@@ -639,25 +598,23 @@ describe('matchOrders', () => {
             // Cancel left order
             await exchangeWrapper.cancelOrderAsync(signedOrderLeft, signedOrderLeft.makerAddress);
             // Match orders
-            return expect(
+            return expectRevertOrAlwaysFailingTransactionAsync(
                 exchangeWrapper.matchOrdersAsync(signedOrderLeft, signedOrderRight, takerAddress),
-            ).to.be.rejectedWith(constants.REVERT);
+            );
         });
 
         it('Should throw if right order is not fillable', async () => {
             // Create orders to match
             const signedOrderLeft = orderFactoryLeft.newSignedOrder({
                 makerAddress: makerAddressLeft,
-                makerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20MakerAssetAddress),
-                takerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20TakerAssetAddress),
                 makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(5), 18),
                 takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(10), 18),
                 feeRecipientAddress: feeRecipientAddressLeft,
             });
             const signedOrderRight = orderFactoryRight.newSignedOrder({
                 makerAddress: makerAddressRight,
-                makerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20TakerAssetAddress),
-                takerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20MakerAssetAddress),
+                makerAssetData: assetProxyUtils.encodeERC20AssetData(defaultERC20TakerAssetAddress),
+                takerAssetData: assetProxyUtils.encodeERC20AssetData(defaultERC20MakerAssetAddress),
                 makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(10), 18),
                 takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(2), 18),
                 feeRecipientAddress: feeRecipientAddressRight,
@@ -665,31 +622,29 @@ describe('matchOrders', () => {
             // Cancel right order
             await exchangeWrapper.cancelOrderAsync(signedOrderRight, signedOrderRight.makerAddress);
             // Match orders
-            return expect(
+            return expectRevertOrAlwaysFailingTransactionAsync(
                 exchangeWrapper.matchOrdersAsync(signedOrderLeft, signedOrderRight, takerAddress),
-            ).to.be.rejectedWith(constants.REVERT);
+            );
         });
 
         it('should throw if there is not a positive spread', async () => {
             // Create orders to match
             const signedOrderLeft = orderFactoryLeft.newSignedOrder({
                 makerAddress: makerAddressLeft,
-                makerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20MakerAssetAddress),
-                takerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20TakerAssetAddress),
                 makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(5), 18),
                 takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(100), 18),
                 feeRecipientAddress: feeRecipientAddressLeft,
             });
             const signedOrderRight = orderFactoryRight.newSignedOrder({
                 makerAddress: makerAddressRight,
-                makerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20TakerAssetAddress),
-                takerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20MakerAssetAddress),
+                makerAssetData: assetProxyUtils.encodeERC20AssetData(defaultERC20TakerAssetAddress),
+                takerAssetData: assetProxyUtils.encodeERC20AssetData(defaultERC20MakerAssetAddress),
                 makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(1), 18),
                 takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(200), 18),
                 feeRecipientAddress: feeRecipientAddressRight,
             });
             // Match orders
-            return expect(
+            return expectRevertOrAlwaysFailingTransactionAsync(
                 matchOrderTester.matchOrdersAndVerifyBalancesAsync(
                     signedOrderLeft,
                     signedOrderRight,
@@ -697,29 +652,27 @@ describe('matchOrders', () => {
                     erc20BalancesByOwner,
                     erc721TokenIdsByOwner,
                 ),
-            ).to.be.rejectedWith(constants.REVERT);
+            );
         });
 
         it('should throw if the left maker asset is not equal to the right taker asset ', async () => {
             // Create orders to match
             const signedOrderLeft = orderFactoryLeft.newSignedOrder({
                 makerAddress: makerAddressLeft,
-                makerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20MakerAssetAddress),
-                takerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20TakerAssetAddress),
                 makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(5), 18),
                 takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(10), 18),
                 feeRecipientAddress: feeRecipientAddressLeft,
             });
             const signedOrderRight = orderFactoryRight.newSignedOrder({
                 makerAddress: makerAddressRight,
-                makerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20TakerAssetAddress),
-                takerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20TakerAssetAddress),
+                makerAssetData: assetProxyUtils.encodeERC20AssetData(defaultERC20TakerAssetAddress),
+                takerAssetData: assetProxyUtils.encodeERC20AssetData(defaultERC20TakerAssetAddress),
                 makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(10), 18),
                 takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(2), 18),
                 feeRecipientAddress: feeRecipientAddressRight,
             });
             // Match orders
-            return expect(
+            return expectRevertOrAlwaysFailingTransactionAsync(
                 matchOrderTester.matchOrdersAndVerifyBalancesAsync(
                     signedOrderLeft,
                     signedOrderRight,
@@ -727,29 +680,29 @@ describe('matchOrders', () => {
                     erc20BalancesByOwner,
                     erc721TokenIdsByOwner,
                 ),
-            ).to.be.rejectedWith(constants.REVERT);
+            );
         });
 
         it('should throw if the right maker asset is not equal to the left taker asset', async () => {
             // Create orders to match
             const signedOrderLeft = orderFactoryLeft.newSignedOrder({
                 makerAddress: makerAddressLeft,
-                makerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20MakerAssetAddress),
-                takerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20MakerAssetAddress),
+                makerAssetData: assetProxyUtils.encodeERC20AssetData(defaultERC20MakerAssetAddress),
+                takerAssetData: assetProxyUtils.encodeERC20AssetData(defaultERC20MakerAssetAddress),
                 makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(5), 18),
                 takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(10), 18),
                 feeRecipientAddress: feeRecipientAddressLeft,
             });
             const signedOrderRight = orderFactoryRight.newSignedOrder({
                 makerAddress: makerAddressRight,
-                makerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20TakerAssetAddress),
-                takerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20MakerAssetAddress),
+                makerAssetData: assetProxyUtils.encodeERC20AssetData(defaultERC20TakerAssetAddress),
+                takerAssetData: assetProxyUtils.encodeERC20AssetData(defaultERC20MakerAssetAddress),
                 makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(10), 18),
                 takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(2), 18),
                 feeRecipientAddress: feeRecipientAddressRight,
             });
             // Match orders
-            return expect(
+            return expectRevertOrAlwaysFailingTransactionAsync(
                 matchOrderTester.matchOrdersAndVerifyBalancesAsync(
                     signedOrderLeft,
                     signedOrderRight,
@@ -757,7 +710,7 @@ describe('matchOrders', () => {
                     erc20BalancesByOwner,
                     erc721TokenIdsByOwner,
                 ),
-            ).to.be.rejectedWith(constants.REVERT);
+            );
         });
 
         it('should transfer correct amounts when left order maker asset is an ERC721 token', async () => {
@@ -765,16 +718,16 @@ describe('matchOrders', () => {
             const erc721TokenToTransfer = erc721LeftMakerAssetIds[0];
             const signedOrderLeft = orderFactoryLeft.newSignedOrder({
                 makerAddress: makerAddressLeft,
-                makerAssetData: assetProxyUtils.encodeERC721ProxyData(defaultERC721AssetAddress, erc721TokenToTransfer),
-                takerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20TakerAssetAddress),
+                makerAssetData: assetProxyUtils.encodeERC721AssetData(defaultERC721AssetAddress, erc721TokenToTransfer),
+                takerAssetData: assetProxyUtils.encodeERC20AssetData(defaultERC20TakerAssetAddress),
                 makerAssetAmount: new BigNumber(1),
                 takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(10), 18),
                 feeRecipientAddress: feeRecipientAddressLeft,
             });
             const signedOrderRight = orderFactoryRight.newSignedOrder({
                 makerAddress: makerAddressRight,
-                makerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20TakerAssetAddress),
-                takerAssetData: assetProxyUtils.encodeERC721ProxyData(defaultERC721AssetAddress, erc721TokenToTransfer),
+                makerAssetData: assetProxyUtils.encodeERC20AssetData(defaultERC20TakerAssetAddress),
+                takerAssetData: assetProxyUtils.encodeERC721AssetData(defaultERC721AssetAddress, erc721TokenToTransfer),
                 makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(10), 18),
                 takerAssetAmount: new BigNumber(1),
                 feeRecipientAddress: feeRecipientAddressRight,
@@ -800,16 +753,16 @@ describe('matchOrders', () => {
             const erc721TokenToTransfer = erc721RightMakerAssetIds[0];
             const signedOrderLeft = orderFactoryLeft.newSignedOrder({
                 makerAddress: makerAddressLeft,
-                makerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20MakerAssetAddress),
-                takerAssetData: assetProxyUtils.encodeERC721ProxyData(defaultERC721AssetAddress, erc721TokenToTransfer),
+                makerAssetData: assetProxyUtils.encodeERC20AssetData(defaultERC20MakerAssetAddress),
+                takerAssetData: assetProxyUtils.encodeERC721AssetData(defaultERC721AssetAddress, erc721TokenToTransfer),
                 makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(10), 18),
                 takerAssetAmount: new BigNumber(1),
                 feeRecipientAddress: feeRecipientAddressLeft,
             });
             const signedOrderRight = orderFactoryRight.newSignedOrder({
                 makerAddress: makerAddressRight,
-                makerAssetData: assetProxyUtils.encodeERC721ProxyData(defaultERC721AssetAddress, erc721TokenToTransfer),
-                takerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultERC20MakerAssetAddress),
+                makerAssetData: assetProxyUtils.encodeERC721AssetData(defaultERC721AssetAddress, erc721TokenToTransfer),
+                takerAssetData: assetProxyUtils.encodeERC20AssetData(defaultERC20MakerAssetAddress),
                 makerAssetAmount: new BigNumber(1),
                 takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(10), 18),
                 feeRecipientAddress: feeRecipientAddressRight,
diff --git a/packages/contracts/test/exchange/signature_validator.ts b/packages/contracts/test/exchange/signature_validator.ts
index 936910ee9..c39fd6ee4 100644
--- a/packages/contracts/test/exchange/signature_validator.ts
+++ b/packages/contracts/test/exchange/signature_validator.ts
@@ -1,11 +1,10 @@
 import { BlockchainLifecycle } from '@0xproject/dev-utils';
 import { assetProxyUtils, orderHashUtils } from '@0xproject/order-utils';
 import { SignedOrder } from '@0xproject/types';
-import { BigNumber } from '@0xproject/utils';
 import * as chai from 'chai';
 import ethUtil = require('ethereumjs-util');
 
-import { TestSignatureValidatorContract } from '../../src/contract_wrappers/generated/test_signature_validator';
+import { TestSignatureValidatorContract } from '../../src/generated_contract_wrappers/test_signature_validator';
 import { addressUtils } from '../../src/utils/address_utils';
 import { artifacts } from '../../src/utils/artifacts';
 import { chaiSetup } from '../../src/utils/chai_setup';
@@ -43,8 +42,8 @@ describe('MixinSignatureValidator', () => {
             exchangeAddress: signatureValidator.address,
             makerAddress,
             feeRecipientAddress: addressUtils.generatePseudoRandomAddress(),
-            makerAssetData: assetProxyUtils.encodeERC20ProxyData(addressUtils.generatePseudoRandomAddress()),
-            takerAssetData: assetProxyUtils.encodeERC20ProxyData(addressUtils.generatePseudoRandomAddress()),
+            makerAssetData: assetProxyUtils.encodeERC20AssetData(addressUtils.generatePseudoRandomAddress()),
+            takerAssetData: assetProxyUtils.encodeERC20AssetData(addressUtils.generatePseudoRandomAddress()),
         };
         const privateKey = constants.TESTRPC_PRIVATE_KEYS[accounts.indexOf(makerAddress)];
         orderFactory = new OrderFactory(privateKey, defaultOrderParams);
diff --git a/packages/contracts/test/exchange/transactions.ts b/packages/contracts/test/exchange/transactions.ts
index f31053ad3..21ff123e5 100644
--- a/packages/contracts/test/exchange/transactions.ts
+++ b/packages/contracts/test/exchange/transactions.ts
@@ -1,16 +1,15 @@
 import { BlockchainLifecycle } from '@0xproject/dev-utils';
 import { assetProxyUtils, generatePseudoRandomSalt } from '@0xproject/order-utils';
-import { AssetProxyId, Order, OrderWithoutExchangeAddress, SignedOrder } from '@0xproject/types';
+import { AssetProxyId, OrderWithoutExchangeAddress, SignedOrder } from '@0xproject/types';
 import { BigNumber } from '@0xproject/utils';
 import * as chai from 'chai';
-import * as ethUtil from 'ethereumjs-util';
-import * as Web3 from 'web3';
 
-import { DummyERC20TokenContract } from '../../src/contract_wrappers/generated/dummy_e_r_c20_token';
-import { ERC20ProxyContract } from '../../src/contract_wrappers/generated/e_r_c20_proxy';
-import { ExchangeContract } from '../../src/contract_wrappers/generated/exchange';
-import { WhitelistContract } from '../../src/contract_wrappers/generated/whitelist';
+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 { WhitelistContract } from '../../src/generated_contract_wrappers/whitelist';
 import { artifacts } from '../../src/utils/artifacts';
+import { expectRevertOrAlwaysFailingTransactionAsync } from '../../src/utils/assertions';
 import { chaiSetup } from '../../src/utils/chai_setup';
 import { constants } from '../../src/utils/constants';
 import { ERC20Wrapper } from '../../src/utils/erc20_wrapper';
@@ -18,7 +17,7 @@ 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, OrderStatus, SignedTransaction } from '../../src/utils/types';
+import { ERC20BalancesByOwner, SignedTransaction } from '../../src/utils/types';
 import { provider, txDefaults, web3Wrapper } from '../../src/utils/web3_wrapper';
 
 chaiSetup.configure();
@@ -73,7 +72,7 @@ describe('Exchange transactions', () => {
             artifacts.Exchange,
             provider,
             txDefaults,
-            assetProxyUtils.encodeERC20ProxyData(zrxToken.address),
+            zrxToken.address,
         );
         exchangeWrapper = new ExchangeWrapper(exchange, provider);
         await exchangeWrapper.registerAssetProxyAsync(AssetProxyId.ERC20, erc20Proxy.address, owner);
@@ -92,8 +91,8 @@ describe('Exchange transactions', () => {
             exchangeAddress: exchange.address,
             makerAddress,
             feeRecipientAddress,
-            makerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultMakerTokenAddress),
-            takerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultTakerTokenAddress),
+            makerAssetData: assetProxyUtils.encodeERC20AssetData(defaultMakerTokenAddress),
+            takerAssetData: assetProxyUtils.encodeERC20AssetData(defaultTakerTokenAddress),
         };
         makerPrivateKey = constants.TESTRPC_PRIVATE_KEYS[accounts.indexOf(makerAddress)];
         takerPrivateKey = constants.TESTRPC_PRIVATE_KEYS[accounts.indexOf(takerAddress)];
@@ -126,8 +125,8 @@ describe('Exchange transactions', () => {
             });
 
             it('should throw if not called by specified sender', async () => {
-                return expect(exchangeWrapper.executeTransactionAsync(signedTx, takerAddress)).to.be.rejectedWith(
-                    constants.REVERT,
+                return expectRevertOrAlwaysFailingTransactionAsync(
+                    exchangeWrapper.executeTransactionAsync(signedTx, takerAddress),
                 );
             });
 
@@ -168,8 +167,8 @@ describe('Exchange transactions', () => {
 
             it('should throw if the a 0x transaction with the same transactionHash has already been executed', async () => {
                 await exchangeWrapper.executeTransactionAsync(signedTx, senderAddress);
-                return expect(exchangeWrapper.executeTransactionAsync(signedTx, senderAddress)).to.be.rejectedWith(
-                    constants.REVERT,
+                return expectRevertOrAlwaysFailingTransactionAsync(
+                    exchangeWrapper.executeTransactionAsync(signedTx, senderAddress),
                 );
             });
 
@@ -187,15 +186,15 @@ describe('Exchange transactions', () => {
             });
 
             it('should throw if not called by specified sender', async () => {
-                return expect(exchangeWrapper.executeTransactionAsync(signedTx, makerAddress)).to.be.rejectedWith(
-                    constants.REVERT,
+                return expectRevertOrAlwaysFailingTransactionAsync(
+                    exchangeWrapper.executeTransactionAsync(signedTx, makerAddress),
                 );
             });
 
             it('should cancel the order when signed by maker and called by sender', async () => {
                 await exchangeWrapper.executeTransactionAsync(signedTx, senderAddress);
-                return expect(exchangeWrapper.fillOrderAsync(signedOrder, senderAddress)).to.be.rejectedWith(
-                    constants.REVERT,
+                return expectRevertOrAlwaysFailingTransactionAsync(
+                    exchangeWrapper.fillOrderAsync(signedOrder, senderAddress),
                 );
             });
         });
@@ -217,6 +216,7 @@ describe('Exchange transactions', () => {
                 await exchange.setSignatureValidatorApproval.sendTransactionAsync(whitelist.address, isApproved, {
                     from: takerAddress,
                 }),
+                constants.AWAIT_TRANSACTION_MINED_MS,
             );
             const defaultOrderParams = {
                 ...constants.STATIC_ORDER_PARAMS,
@@ -224,8 +224,8 @@ describe('Exchange transactions', () => {
                 exchangeAddress: exchange.address,
                 makerAddress,
                 feeRecipientAddress,
-                makerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultMakerTokenAddress),
-                takerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultTakerTokenAddress),
+                makerAssetData: assetProxyUtils.encodeERC20AssetData(defaultMakerTokenAddress),
+                takerAssetData: assetProxyUtils.encodeERC20AssetData(defaultTakerTokenAddress),
             };
             whitelistOrderFactory = new OrderFactory(makerPrivateKey, defaultOrderParams);
         });
@@ -239,12 +239,13 @@ describe('Exchange transactions', () => {
             const isApproved = true;
             await web3Wrapper.awaitTransactionSuccessAsync(
                 await whitelist.updateWhitelistStatus.sendTransactionAsync(takerAddress, isApproved, { from: owner }),
+                constants.AWAIT_TRANSACTION_MINED_MS,
             );
 
             orderWithoutExchangeAddress = orderUtils.getOrderWithoutExchangeAddress(signedOrder);
             const takerAssetFillAmount = signedOrder.takerAssetAmount;
             const salt = generatePseudoRandomSalt();
-            return expect(
+            return expectRevertOrAlwaysFailingTransactionAsync(
                 whitelist.fillOrderIfWhitelisted.sendTransactionAsync(
                     orderWithoutExchangeAddress,
                     takerAssetFillAmount,
@@ -252,19 +253,20 @@ describe('Exchange transactions', () => {
                     signedOrder.signature,
                     { from: takerAddress },
                 ),
-            ).to.be.rejectedWith(constants.REVERT);
+            );
         });
 
         it('should revert if taker has not been whitelisted', async () => {
             const isApproved = true;
             await web3Wrapper.awaitTransactionSuccessAsync(
                 await whitelist.updateWhitelistStatus.sendTransactionAsync(makerAddress, isApproved, { from: owner }),
+                constants.AWAIT_TRANSACTION_MINED_MS,
             );
 
             orderWithoutExchangeAddress = orderUtils.getOrderWithoutExchangeAddress(signedOrder);
             const takerAssetFillAmount = signedOrder.takerAssetAmount;
             const salt = generatePseudoRandomSalt();
-            return expect(
+            return expectRevertOrAlwaysFailingTransactionAsync(
                 whitelist.fillOrderIfWhitelisted.sendTransactionAsync(
                     orderWithoutExchangeAddress,
                     takerAssetFillAmount,
@@ -272,17 +274,19 @@ describe('Exchange transactions', () => {
                     signedOrder.signature,
                     { from: takerAddress },
                 ),
-            ).to.be.rejectedWith(constants.REVERT);
+            );
         });
 
         it('should fill the order if maker and taker have been whitelisted', async () => {
             const isApproved = true;
             await web3Wrapper.awaitTransactionSuccessAsync(
                 await whitelist.updateWhitelistStatus.sendTransactionAsync(makerAddress, isApproved, { from: owner }),
+                constants.AWAIT_TRANSACTION_MINED_MS,
             );
 
             await web3Wrapper.awaitTransactionSuccessAsync(
                 await whitelist.updateWhitelistStatus.sendTransactionAsync(takerAddress, isApproved, { from: owner }),
+                constants.AWAIT_TRANSACTION_MINED_MS,
             );
 
             orderWithoutExchangeAddress = orderUtils.getOrderWithoutExchangeAddress(signedOrder);
@@ -296,6 +300,7 @@ describe('Exchange transactions', () => {
                     signedOrder.signature,
                     { from: takerAddress },
                 ),
+                constants.AWAIT_TRANSACTION_MINED_MS,
             );
 
             const newBalances = await erc20Wrapper.getBalancesAsync();
diff --git a/packages/contracts/test/exchange/wrapper.ts b/packages/contracts/test/exchange/wrapper.ts
index 583ec9f91..abba1ac4f 100644
--- a/packages/contracts/test/exchange/wrapper.ts
+++ b/packages/contracts/test/exchange/wrapper.ts
@@ -1,4 +1,4 @@
-import { BlockchainLifecycle, devConstants, web3Factory } from '@0xproject/dev-utils';
+import { BlockchainLifecycle } from '@0xproject/dev-utils';
 import { assetProxyUtils } from '@0xproject/order-utils';
 import { AssetProxyId, SignedOrder } from '@0xproject/types';
 import { BigNumber } from '@0xproject/utils';
@@ -6,15 +6,14 @@ import { Web3Wrapper } from '@0xproject/web3-wrapper';
 import * as chai from 'chai';
 import * as _ from 'lodash';
 import 'make-promises-safe';
-import * as Web3 from 'web3';
-
-import { DummyERC20TokenContract } from '../../src/contract_wrappers/generated/dummy_e_r_c20_token';
-import { DummyERC721TokenContract } from '../../src/contract_wrappers/generated/dummy_e_r_c721_token';
-import { ERC20ProxyContract } from '../../src/contract_wrappers/generated/e_r_c20_proxy';
-import { ERC721ProxyContract } from '../../src/contract_wrappers/generated/e_r_c721_proxy';
-import { ExchangeContract } from '../../src/contract_wrappers/generated/exchange';
-import { TokenRegistryContract } from '../../src/contract_wrappers/generated/token_registry';
+
+import { DummyERC20TokenContract } from '../../src/generated_contract_wrappers/dummy_e_r_c20_token';
+import { DummyERC721TokenContract } from '../../src/generated_contract_wrappers/dummy_e_r_c721_token';
+import { ERC20ProxyContract } from '../../src/generated_contract_wrappers/e_r_c20_proxy';
+import { ERC721ProxyContract } from '../../src/generated_contract_wrappers/e_r_c721_proxy';
+import { ExchangeContract } from '../../src/generated_contract_wrappers/exchange';
 import { artifacts } from '../../src/utils/artifacts';
+import { expectRevertOrAlwaysFailingTransactionAsync } from '../../src/utils/assertions';
 import { chaiSetup } from '../../src/utils/chai_setup';
 import { constants } from '../../src/utils/constants';
 import { ERC20Wrapper } from '../../src/utils/erc20_wrapper';
@@ -82,7 +81,7 @@ describe('Exchange wrappers', () => {
             artifacts.Exchange,
             provider,
             txDefaults,
-            assetProxyUtils.encodeERC20ProxyData(zrxToken.address),
+            zrxToken.address,
         );
         exchangeWrapper = new ExchangeWrapper(exchange, provider);
         await exchangeWrapper.registerAssetProxyAsync(AssetProxyId.ERC20, erc20Proxy.address, owner);
@@ -109,8 +108,8 @@ describe('Exchange wrappers', () => {
             exchangeAddress: exchange.address,
             makerAddress,
             feeRecipientAddress,
-            makerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultMakerAssetAddress),
-            takerAssetData: assetProxyUtils.encodeERC20ProxyData(defaultTakerAssetAddress),
+            makerAssetData: assetProxyUtils.encodeERC20AssetData(defaultMakerAssetAddress),
+            takerAssetData: assetProxyUtils.encodeERC20AssetData(defaultTakerAssetAddress),
         };
         const privateKey = constants.TESTRPC_PRIVATE_KEYS[accounts.indexOf(makerAddress)];
         orderFactory = new OrderFactory(privateKey, defaultOrderParams);
@@ -172,8 +171,8 @@ describe('Exchange wrappers', () => {
                 expirationTimeSeconds: new BigNumber(Math.floor((Date.now() - 10000) / 1000)),
             });
 
-            return expect(exchangeWrapper.fillOrKillOrderAsync(signedOrder, takerAddress)).to.be.rejectedWith(
-                constants.REVERT,
+            return expectRevertOrAlwaysFailingTransactionAsync(
+                exchangeWrapper.fillOrKillOrderAsync(signedOrder, takerAddress),
             );
         });
 
@@ -184,8 +183,8 @@ describe('Exchange wrappers', () => {
                 takerAssetFillAmount: signedOrder.takerAssetAmount.div(2),
             });
 
-            return expect(exchangeWrapper.fillOrKillOrderAsync(signedOrder, takerAddress)).to.be.rejectedWith(
-                constants.REVERT,
+            return expectRevertOrAlwaysFailingTransactionAsync(
+                exchangeWrapper.fillOrKillOrderAsync(signedOrder, takerAddress),
             );
         });
     });
@@ -197,12 +196,16 @@ describe('Exchange wrappers', () => {
                 takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(200), 18),
             });
             const takerAssetFillAmount = signedOrder.takerAssetAmount.div(2);
+
             await exchangeWrapper.fillOrderNoThrowAsync(signedOrder, takerAddress, {
                 takerAssetFillAmount,
+                // HACK(albrow): We need to hardcode the gas estimate here because
+                // the Geth gas estimator doesn't work with the way we use
+                // delegatecall and swallow errors.
+                gas: 250000,
             });
 
             const newBalances = await erc20Wrapper.getBalancesAsync();
-
             const makerAssetFilledAmount = takerAssetFillAmount
                 .times(signedOrder.makerAssetAmount)
                 .dividedToIntegerBy(signedOrder.takerAssetAmount);
@@ -212,6 +215,7 @@ describe('Exchange wrappers', () => {
             const takerFee = signedOrder.takerFee
                 .times(makerAssetFilledAmount)
                 .dividedToIntegerBy(signedOrder.makerAssetAmount);
+
             expect(newBalances[makerAddress][defaultMakerAssetAddress]).to.be.bignumber.equal(
                 erc20Balances[makerAddress][defaultMakerAssetAddress].minus(makerAssetFilledAmount),
             );
@@ -300,7 +304,7 @@ describe('Exchange wrappers', () => {
             const signedOrder = orderFactory.newSignedOrder({
                 makerAssetAmount: makerZRXBalance,
                 makerFee: new BigNumber(1),
-                makerAssetData: assetProxyUtils.encodeERC20ProxyData(zrxToken.address),
+                makerAssetData: assetProxyUtils.encodeERC20AssetData(zrxToken.address),
             });
             await exchangeWrapper.fillOrderNoThrowAsync(signedOrder, takerAddress);
             const newBalances = await erc20Wrapper.getBalancesAsync();
@@ -312,7 +316,7 @@ describe('Exchange wrappers', () => {
             const signedOrder = orderFactory.newSignedOrder({
                 makerAssetAmount: new BigNumber(makerZRXAllowance),
                 makerFee: new BigNumber(1),
-                makerAssetData: assetProxyUtils.encodeERC20ProxyData(zrxToken.address),
+                makerAssetData: assetProxyUtils.encodeERC20AssetData(zrxToken.address),
             });
             await exchangeWrapper.fillOrderNoThrowAsync(signedOrder, takerAddress);
             const newBalances = await erc20Wrapper.getBalancesAsync();
@@ -324,7 +328,7 @@ describe('Exchange wrappers', () => {
             const signedOrder = orderFactory.newSignedOrder({
                 takerAssetAmount: takerZRXBalance,
                 takerFee: new BigNumber(1),
-                takerAssetData: assetProxyUtils.encodeERC20ProxyData(zrxToken.address),
+                takerAssetData: assetProxyUtils.encodeERC20AssetData(zrxToken.address),
             });
             await exchangeWrapper.fillOrderNoThrowAsync(signedOrder, takerAddress);
             const newBalances = await erc20Wrapper.getBalancesAsync();
@@ -336,7 +340,7 @@ describe('Exchange wrappers', () => {
             const signedOrder = orderFactory.newSignedOrder({
                 takerAssetAmount: new BigNumber(takerZRXAllowance),
                 takerFee: new BigNumber(1),
-                takerAssetData: assetProxyUtils.encodeERC20ProxyData(zrxToken.address),
+                takerAssetData: assetProxyUtils.encodeERC20AssetData(zrxToken.address),
             });
             await exchangeWrapper.fillOrderNoThrowAsync(signedOrder, takerAddress);
             const newBalances = await erc20Wrapper.getBalancesAsync();
@@ -350,8 +354,8 @@ describe('Exchange wrappers', () => {
             const signedOrder = orderFactory.newSignedOrder({
                 makerAssetAmount: new BigNumber(1),
                 takerAssetAmount: new BigNumber(1),
-                makerAssetData: assetProxyUtils.encodeERC721ProxyData(erc721Token.address, makerAssetId),
-                takerAssetData: assetProxyUtils.encodeERC721ProxyData(erc721Token.address, takerAssetId),
+                makerAssetData: assetProxyUtils.encodeERC721AssetData(erc721Token.address, makerAssetId),
+                takerAssetData: assetProxyUtils.encodeERC721AssetData(erc721Token.address, takerAssetId),
             });
             // Verify pre-conditions
             const initialOwnerMakerAsset = await erc721Token.ownerOf.callAsync(makerAssetId);
@@ -360,7 +364,13 @@ describe('Exchange wrappers', () => {
             expect(initialOwnerTakerAsset).to.be.bignumber.equal(takerAddress);
             // Call Exchange
             const takerAssetFillAmount = signedOrder.takerAssetAmount;
-            await exchangeWrapper.fillOrderNoThrowAsync(signedOrder, takerAddress, { takerAssetFillAmount });
+            await exchangeWrapper.fillOrderNoThrowAsync(signedOrder, takerAddress, {
+                takerAssetFillAmount,
+                // HACK(albrow): We need to hardcode the gas estimate here because
+                // the Geth gas estimator doesn't work with the way we use
+                // delegatecall and swallow errors.
+                gas: 270000,
+            });
             // Verify post-conditions
             const newOwnerMakerAsset = await erc721Token.ownerOf.callAsync(makerAssetId);
             expect(newOwnerMakerAsset).to.be.bignumber.equal(takerAddress);
@@ -485,11 +495,11 @@ describe('Exchange wrappers', () => {
 
                 await exchangeWrapper.fillOrKillOrderAsync(signedOrders[0], takerAddress);
 
-                return expect(
+                return expectRevertOrAlwaysFailingTransactionAsync(
                     exchangeWrapper.batchFillOrKillOrdersAsync(signedOrders, takerAddress, {
                         takerAssetFillAmounts,
                     }),
-                ).to.be.rejectedWith(constants.REVERT);
+                );
             });
         });
 
@@ -535,6 +545,10 @@ describe('Exchange wrappers', () => {
 
                 await exchangeWrapper.batchFillOrdersNoThrowAsync(signedOrders, takerAddress, {
                     takerAssetFillAmounts,
+                    // HACK(albrow): We need to hardcode the gas estimate here because
+                    // the Geth gas estimator doesn't work with the way we use
+                    // delegatecall and swallow errors.
+                    gas: 600000,
                 });
 
                 const newBalances = await erc20Wrapper.getBalancesAsync();
@@ -591,6 +605,10 @@ describe('Exchange wrappers', () => {
                 const newOrders = [invalidOrder, ...validOrders];
                 await exchangeWrapper.batchFillOrdersNoThrowAsync(newOrders, takerAddress, {
                     takerAssetFillAmounts,
+                    // HACK(albrow): We need to hardcode the gas estimate here because
+                    // the Geth gas estimator doesn't work with the way we use
+                    // delegatecall and swallow errors.
+                    gas: 450000,
                 });
 
                 const newBalances = await erc20Wrapper.getBalancesAsync();
@@ -674,16 +692,16 @@ describe('Exchange wrappers', () => {
                 signedOrders = [
                     orderFactory.newSignedOrder(),
                     orderFactory.newSignedOrder({
-                        takerAssetData: assetProxyUtils.encodeERC20ProxyData(zrxToken.address),
+                        takerAssetData: assetProxyUtils.encodeERC20AssetData(zrxToken.address),
                     }),
                     orderFactory.newSignedOrder(),
                 ];
 
-                return expect(
+                return expectRevertOrAlwaysFailingTransactionAsync(
                     exchangeWrapper.marketSellOrdersAsync(signedOrders, takerAddress, {
                         takerAssetFillAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(1000), 18),
                     }),
-                ).to.be.rejectedWith(constants.REVERT);
+                );
             });
         });
 
@@ -694,6 +712,10 @@ describe('Exchange wrappers', () => {
                 );
                 await exchangeWrapper.marketSellOrdersNoThrowAsync(signedOrders, takerAddress, {
                     takerAssetFillAmount,
+                    // HACK(albrow): We need to hardcode the gas estimate here because
+                    // the Geth gas estimator doesn't work with the way we use
+                    // delegatecall and swallow errors.
+                    gas: 6000000,
                 });
 
                 const newBalances = await erc20Wrapper.getBalancesAsync();
@@ -753,26 +775,59 @@ describe('Exchange wrappers', () => {
                 });
                 await exchangeWrapper.marketSellOrdersNoThrowAsync(signedOrders, takerAddress, {
                     takerAssetFillAmount,
+                    // HACK(albrow): We need to hardcode the gas estimate here because
+                    // the Geth gas estimator doesn't work with the way we use
+                    // delegatecall and swallow errors.
+                    gas: 600000,
                 });
 
                 const newBalances = await erc20Wrapper.getBalancesAsync();
                 expect(newBalances).to.be.deep.equal(erc20Balances);
             });
 
-            it('should throw when a signedOrder does not use the same takerAssetAddress', async () => {
+            it('should not fill a signedOrder that does not use the same takerAssetAddress', async () => {
                 signedOrders = [
                     orderFactory.newSignedOrder(),
+                    orderFactory.newSignedOrder(),
                     orderFactory.newSignedOrder({
-                        takerAssetData: assetProxyUtils.encodeERC20ProxyData(zrxToken.address),
+                        takerAssetData: assetProxyUtils.encodeERC20AssetData(zrxToken.address),
                     }),
-                    orderFactory.newSignedOrder(),
                 ];
+                const takerAssetFillAmount = Web3Wrapper.toBaseUnitAmount(new BigNumber(100000), 18);
+                const filledSignedOrders = signedOrders.slice(0, -1);
+                _.forEach(filledSignedOrders, signedOrder => {
+                    erc20Balances[makerAddress][defaultMakerAssetAddress] = erc20Balances[makerAddress][
+                        defaultMakerAssetAddress
+                    ].minus(signedOrder.makerAssetAmount);
+                    erc20Balances[makerAddress][defaultTakerAssetAddress] = erc20Balances[makerAddress][
+                        defaultTakerAssetAddress
+                    ].add(signedOrder.takerAssetAmount);
+                    erc20Balances[makerAddress][zrxToken.address] = erc20Balances[makerAddress][zrxToken.address].minus(
+                        signedOrder.makerFee,
+                    );
+                    erc20Balances[takerAddress][defaultMakerAssetAddress] = erc20Balances[takerAddress][
+                        defaultMakerAssetAddress
+                    ].add(signedOrder.makerAssetAmount);
+                    erc20Balances[takerAddress][defaultTakerAssetAddress] = erc20Balances[takerAddress][
+                        defaultTakerAssetAddress
+                    ].minus(signedOrder.takerAssetAmount);
+                    erc20Balances[takerAddress][zrxToken.address] = erc20Balances[takerAddress][zrxToken.address].minus(
+                        signedOrder.takerFee,
+                    );
+                    erc20Balances[feeRecipientAddress][zrxToken.address] = erc20Balances[feeRecipientAddress][
+                        zrxToken.address
+                    ].add(signedOrder.makerFee.add(signedOrder.takerFee));
+                });
+                await exchangeWrapper.marketSellOrdersNoThrowAsync(signedOrders, takerAddress, {
+                    takerAssetFillAmount,
+                    // HACK(albrow): We need to hardcode the gas estimate here because
+                    // the Geth gas estimator doesn't work with the way we use
+                    // delegatecall and swallow errors.
+                    gas: 600000,
+                });
 
-                return expect(
-                    exchangeWrapper.marketSellOrdersNoThrowAsync(signedOrders, takerAddress, {
-                        takerAssetFillAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(1000), 18),
-                    }),
-                ).to.be.rejectedWith(constants.REVERT);
+                const newBalances = await erc20Wrapper.getBalancesAsync();
+                expect(newBalances).to.be.deep.equal(erc20Balances);
             });
         });
 
@@ -852,16 +907,16 @@ describe('Exchange wrappers', () => {
                 signedOrders = [
                     orderFactory.newSignedOrder(),
                     orderFactory.newSignedOrder({
-                        makerAssetData: assetProxyUtils.encodeERC20ProxyData(zrxToken.address),
+                        makerAssetData: assetProxyUtils.encodeERC20AssetData(zrxToken.address),
                     }),
                     orderFactory.newSignedOrder(),
                 ];
 
-                return expect(
+                return expectRevertOrAlwaysFailingTransactionAsync(
                     exchangeWrapper.marketBuyOrdersAsync(signedOrders, takerAddress, {
                         makerAssetFillAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(1000), 18),
                     }),
-                ).to.be.rejectedWith(constants.REVERT);
+                );
             });
         });
 
@@ -872,6 +927,10 @@ describe('Exchange wrappers', () => {
                 );
                 await exchangeWrapper.marketBuyOrdersNoThrowAsync(signedOrders, takerAddress, {
                     makerAssetFillAmount,
+                    // HACK(albrow): We need to hardcode the gas estimate here because
+                    // the Geth gas estimator doesn't work with the way we use
+                    // delegatecall and swallow errors.
+                    gas: 600000,
                 });
 
                 const newBalances = await erc20Wrapper.getBalancesAsync();
@@ -904,8 +963,8 @@ describe('Exchange wrappers', () => {
                 );
             });
 
-            it('should fill all signedOrders if cannot fill entire takerAssetFillAmount', async () => {
-                const takerAssetFillAmount = Web3Wrapper.toBaseUnitAmount(new BigNumber(100000), 18);
+            it('should fill all signedOrders if cannot fill entire makerAssetFillAmount', async () => {
+                const makerAssetFillAmount = Web3Wrapper.toBaseUnitAmount(new BigNumber(100000), 18);
                 _.forEach(signedOrders, signedOrder => {
                     erc20Balances[makerAddress][defaultMakerAssetAddress] = erc20Balances[makerAddress][
                         defaultMakerAssetAddress
@@ -929,28 +988,62 @@ describe('Exchange wrappers', () => {
                         zrxToken.address
                     ].add(signedOrder.makerFee.add(signedOrder.takerFee));
                 });
-                await exchangeWrapper.marketSellOrdersNoThrowAsync(signedOrders, takerAddress, {
-                    takerAssetFillAmount,
+                await exchangeWrapper.marketBuyOrdersNoThrowAsync(signedOrders, takerAddress, {
+                    makerAssetFillAmount,
+                    // HACK(albrow): We need to hardcode the gas estimate here because
+                    // the Geth gas estimator doesn't work with the way we use
+                    // delegatecall and swallow errors.
+                    gas: 600000,
                 });
 
                 const newBalances = await erc20Wrapper.getBalancesAsync();
                 expect(newBalances).to.be.deep.equal(erc20Balances);
             });
 
-            it('should throw when a signedOrder does not use the same makerAssetAddress', async () => {
+            it('should not fill a signedOrder that does not use the same makerAssetAddress', async () => {
                 signedOrders = [
                     orderFactory.newSignedOrder(),
+                    orderFactory.newSignedOrder(),
                     orderFactory.newSignedOrder({
-                        makerAssetData: assetProxyUtils.encodeERC20ProxyData(zrxToken.address),
+                        makerAssetData: assetProxyUtils.encodeERC20AssetData(zrxToken.address),
                     }),
-                    orderFactory.newSignedOrder(),
                 ];
 
-                return expect(
-                    exchangeWrapper.marketBuyOrdersNoThrowAsync(signedOrders, takerAddress, {
-                        makerAssetFillAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(1000), 18),
-                    }),
-                ).to.be.rejectedWith(constants.REVERT);
+                const makerAssetFillAmount = Web3Wrapper.toBaseUnitAmount(new BigNumber(100000), 18);
+                const filledSignedOrders = signedOrders.slice(0, -1);
+                _.forEach(filledSignedOrders, signedOrder => {
+                    erc20Balances[makerAddress][defaultMakerAssetAddress] = erc20Balances[makerAddress][
+                        defaultMakerAssetAddress
+                    ].minus(signedOrder.makerAssetAmount);
+                    erc20Balances[makerAddress][defaultTakerAssetAddress] = erc20Balances[makerAddress][
+                        defaultTakerAssetAddress
+                    ].add(signedOrder.takerAssetAmount);
+                    erc20Balances[makerAddress][zrxToken.address] = erc20Balances[makerAddress][zrxToken.address].minus(
+                        signedOrder.makerFee,
+                    );
+                    erc20Balances[takerAddress][defaultMakerAssetAddress] = erc20Balances[takerAddress][
+                        defaultMakerAssetAddress
+                    ].add(signedOrder.makerAssetAmount);
+                    erc20Balances[takerAddress][defaultTakerAssetAddress] = erc20Balances[takerAddress][
+                        defaultTakerAssetAddress
+                    ].minus(signedOrder.takerAssetAmount);
+                    erc20Balances[takerAddress][zrxToken.address] = erc20Balances[takerAddress][zrxToken.address].minus(
+                        signedOrder.takerFee,
+                    );
+                    erc20Balances[feeRecipientAddress][zrxToken.address] = erc20Balances[feeRecipientAddress][
+                        zrxToken.address
+                    ].add(signedOrder.makerFee.add(signedOrder.takerFee));
+                });
+                await exchangeWrapper.marketBuyOrdersNoThrowAsync(signedOrders, takerAddress, {
+                    makerAssetFillAmount,
+                    // HACK(albrow): We need to hardcode the gas estimate here because
+                    // the Geth gas estimator doesn't work with the way we use
+                    // delegatecall and swallow errors.
+                    gas: 600000,
+                });
+
+                const newBalances = await erc20Wrapper.getBalancesAsync();
+                expect(newBalances).to.be.deep.equal(erc20Balances);
             });
         });
 
diff --git a/packages/contracts/test/global_hooks.ts b/packages/contracts/test/global_hooks.ts
index 8b48b030d..83263c5b3 100644
--- a/packages/contracts/test/global_hooks.ts
+++ b/packages/contracts/test/global_hooks.ts
@@ -1,10 +1,15 @@
 import { env, EnvVars } from '@0xproject/dev-utils';
 
 import { coverage } from '../src/utils/coverage';
+import { profiler } from '../src/utils/profiler';
 
 after('generate coverage report', async () => {
     if (env.parseBoolean(EnvVars.SolidityCoverage)) {
         const coverageSubprovider = coverage.getCoverageSubproviderSingleton();
         await coverageSubprovider.writeCoverageAsync();
     }
+    if (env.parseBoolean(EnvVars.SolidityProfiler)) {
+        const profilerSubprovider = profiler.getProfilerSubproviderSingleton();
+        await profilerSubprovider.writeProfilerOutputAsync();
+    }
 });
diff --git a/packages/contracts/test/libraries/lib_bytes.ts b/packages/contracts/test/libraries/lib_bytes.ts
index 26cfa8291..a31a4789c 100644
--- a/packages/contracts/test/libraries/lib_bytes.ts
+++ b/packages/contracts/test/libraries/lib_bytes.ts
@@ -1,15 +1,14 @@
-import { BlockchainLifecycle, devConstants, web3Factory } from '@0xproject/dev-utils';
-import { AssetProxyId } from '@0xproject/types';
+import { BlockchainLifecycle } from '@0xproject/dev-utils';
+import { assetProxyUtils, generatePseudoRandomSalt } from '@0xproject/order-utils';
 import { BigNumber } from '@0xproject/utils';
-import { Web3Wrapper } from '@0xproject/web3-wrapper';
 import BN = require('bn.js');
 import * as chai from 'chai';
-import { LogWithDecodedArgs, TransactionReceiptWithDecodedLogs } from 'ethereum-types';
 import ethUtil = require('ethereumjs-util');
-import * as Web3 from 'web3';
+import * as _ from 'lodash';
 
-import { TestLibBytesContract } from '../../src/contract_wrappers/generated/test_lib_bytes';
+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';
@@ -19,7 +18,6 @@ const expect = chai.expect;
 const blockchainLifecycle = new BlockchainLifecycle(web3Wrapper);
 
 describe('LibBytes', () => {
-    let owner: string;
     let libBytes: TestLibBytesContract;
     const byteArrayShorterThan32Bytes = '0x012345';
     const byteArrayShorterThan20Bytes = byteArrayShorterThan32Bytes;
@@ -30,8 +28,20 @@ describe('LibBytes', () => {
     const byteArrayLongerThan32BytesLastBytesSwapped =
         '0x0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef0123456789abefcd';
     let testAddress: string;
+    let testAddressB: string;
     const testBytes32 = '0x102030405060708090a0b0c0d0e0f0102030405060708090a0b0c0d0e0f01020';
+    const testBytes32B = '0x534877abd8443578526845cdfef020047528759477fedef87346527659aced32';
     const testUint256 = new BigNumber(testBytes32, 16);
+    const testUint256B = new BigNumber(testBytes32B, 16);
+    let shortData: string;
+    let shortTestBytes: string;
+    let shortTestBytesAsBuffer: Buffer;
+    let wordOfData: string;
+    let wordOfTestBytes: string;
+    let wordOfTestBytesAsBuffer: Buffer;
+    let longData: string;
+    let longTestBytes: string;
+    let longTestBytesAsBuffer: Buffer;
 
     before(async () => {
         await blockchainLifecycle.startAsync();
@@ -42,8 +52,8 @@ describe('LibBytes', () => {
     before(async () => {
         // Setup accounts & addresses
         const accounts = await web3Wrapper.getAvailableAddressesAsync();
-        owner = accounts[0];
         testAddress = accounts[1];
+        testAddressB = accounts[2];
         // Deploy LibBytes
         libBytes = await TestLibBytesContract.deployFrom0xArtifactAsync(artifacts.TestLibBytes, provider, txDefaults);
         // Verify lengths of test data
@@ -53,6 +63,26 @@ describe('LibBytes', () => {
         expect(byteArrayLongerThan32BytesLength).to.be.greaterThan(32);
         const testBytes32Length = ethUtil.toBuffer(testBytes32).byteLength;
         expect(testBytes32Length).to.be.equal(32);
+        // Create short test bytes
+        shortData = '0xffffaa';
+        const encodedShortData = ethUtil.toBuffer(shortData);
+        const shortDataLength = new BigNumber(encodedShortData.byteLength);
+        const encodedShortDataLength = assetProxyUtils.encodeUint256(shortDataLength);
+        shortTestBytesAsBuffer = Buffer.concat([encodedShortDataLength, encodedShortData]);
+        shortTestBytes = ethUtil.bufferToHex(shortTestBytesAsBuffer);
+        // Create test bytes one word in length
+        wordOfData = ethUtil.bufferToHex(assetProxyUtils.encodeUint256(generatePseudoRandomSalt()));
+        const encodedWordOfData = ethUtil.toBuffer(wordOfData);
+        const wordOfDataLength = new BigNumber(encodedWordOfData.byteLength);
+        const encodedWordOfDataLength = assetProxyUtils.encodeUint256(wordOfDataLength);
+        wordOfTestBytesAsBuffer = Buffer.concat([encodedWordOfDataLength, encodedWordOfData]);
+        wordOfTestBytes = ethUtil.bufferToHex(wordOfTestBytesAsBuffer);
+        // Create long test bytes (combines short test bytes with word of test bytes)
+        longData = ethUtil.bufferToHex(Buffer.concat([encodedShortData, encodedWordOfData]));
+        const longDataLength = new BigNumber(encodedShortData.byteLength + encodedWordOfData.byteLength);
+        const encodedLongDataLength = assetProxyUtils.encodeUint256(longDataLength);
+        longTestBytesAsBuffer = Buffer.concat([encodedLongDataLength, encodedShortData, encodedWordOfData]);
+        longTestBytes = ethUtil.bufferToHex(longTestBytesAsBuffer);
     });
     beforeEach(async () => {
         await blockchainLifecycle.startAsync();
@@ -61,13 +91,15 @@ describe('LibBytes', () => {
         await blockchainLifecycle.revertAsync();
     });
 
-    describe('popByte', () => {
+    describe('popLastByte', () => {
         it('should revert if length is 0', async () => {
-            return expect(libBytes.publicPopByte.callAsync(constants.NULL_BYTES)).to.be.rejectedWith(constants.REVERT);
+            return expectRevertOrOtherErrorAsync(
+                libBytes.publicPopLastByte.callAsync(constants.NULL_BYTES),
+                constants.LIB_BYTES_GREATER_THAN_ZERO_LENGTH_REQUIRED,
+            );
         });
-
         it('should pop the last byte from the input and return it', async () => {
-            const [newBytes, poppedByte] = await libBytes.publicPopByte.callAsync(byteArrayLongerThan32Bytes);
+            const [newBytes, poppedByte] = await libBytes.publicPopLastByte.callAsync(byteArrayLongerThan32Bytes);
             const expectedNewBytes = byteArrayLongerThan32Bytes.slice(0, -2);
             const expectedPoppedByte = `0x${byteArrayLongerThan32Bytes.slice(-2)}`;
             expect(newBytes).to.equal(expectedNewBytes);
@@ -75,15 +107,15 @@ describe('LibBytes', () => {
         });
     });
 
-    describe('popAddress', () => {
+    describe('popLast20Bytes', () => {
         it('should revert if length is less than 20', async () => {
-            return expect(libBytes.publicPopAddress.callAsync(byteArrayShorterThan20Bytes)).to.be.rejectedWith(
-                constants.REVERT,
+            return expectRevertOrOtherErrorAsync(
+                libBytes.publicPopLast20Bytes.callAsync(byteArrayShorterThan20Bytes),
+                constants.LIB_BYTES_GREATER_OR_EQUAL_TO_20_LENGTH_REQUIRED,
             );
         });
-
         it('should pop the last 20 bytes from the input and return it', async () => {
-            const [newBytes, poppedAddress] = await libBytes.publicPopAddress.callAsync(byteArrayLongerThan32Bytes);
+            const [newBytes, poppedAddress] = await libBytes.publicPopLast20Bytes.callAsync(byteArrayLongerThan32Bytes);
             const expectedNewBytes = byteArrayLongerThan32Bytes.slice(0, -40);
             const expectedPoppedAddress = `0x${byteArrayLongerThan32Bytes.slice(-40)}`;
             expect(newBytes).to.equal(expectedNewBytes);
@@ -99,7 +131,6 @@ describe('LibBytes', () => {
             );
             return expect(areBytesEqual).to.be.true();
         });
-
         it('should return true if byte arrays are equal (both arrays > 32 bytes)', async () => {
             const areBytesEqual = await libBytes.publicAreBytesEqual.callAsync(
                 byteArrayLongerThan32Bytes,
@@ -107,7 +138,6 @@ describe('LibBytes', () => {
             );
             return expect(areBytesEqual).to.be.true();
         });
-
         it('should return false if byte arrays are not equal (first array < 32 bytes, second array > 32 bytes)', async () => {
             const areBytesEqual = await libBytes.publicAreBytesEqual.callAsync(
                 byteArrayShorterThan32Bytes,
@@ -115,7 +145,6 @@ describe('LibBytes', () => {
             );
             return expect(areBytesEqual).to.be.false();
         });
-
         it('should return false if byte arrays are not equal (first array > 32 bytes, second array < 32 bytes)', async () => {
             const areBytesEqual = await libBytes.publicAreBytesEqual.callAsync(
                 byteArrayLongerThan32Bytes,
@@ -123,7 +152,6 @@ describe('LibBytes', () => {
             );
             return expect(areBytesEqual).to.be.false();
         });
-
         it('should return false if byte arrays are not equal (same length, but a byte in first word differs)', async () => {
             const areBytesEqual = await libBytes.publicAreBytesEqual.callAsync(
                 byteArrayLongerThan32BytesFirstBytesSwapped,
@@ -131,7 +159,6 @@ describe('LibBytes', () => {
             );
             return expect(areBytesEqual).to.be.false();
         });
-
         it('should return false if byte arrays are not equal (same length, but a byte in last word differs)', async () => {
             const areBytesEqual = await libBytes.publicAreBytesEqual.callAsync(
                 byteArrayLongerThan32BytesLastBytesSwapped,
@@ -141,15 +168,50 @@ describe('LibBytes', () => {
         });
     });
 
+    describe('deepCopyBytes', () => {
+        it('should revert if dest is shorter than source', async () => {
+            return expectRevertOrOtherErrorAsync(
+                libBytes.publicDeepCopyBytes.callAsync(byteArrayShorterThan32Bytes, byteArrayLongerThan32Bytes),
+                constants.LIB_BYTES_GREATER_OR_EQUAL_TO_SOURCE_BYTES_LENGTH_REQUIRED,
+            );
+        });
+        it('should overwrite dest with source if source and dest have equal length', async () => {
+            const zeroedByteArrayLongerThan32Bytes = `0x${_.repeat('0', byteArrayLongerThan32Bytes.length - 2)}`;
+            const zeroedBytesAfterCopy = await libBytes.publicDeepCopyBytes.callAsync(
+                zeroedByteArrayLongerThan32Bytes,
+                byteArrayLongerThan32Bytes,
+            );
+            return expect(zeroedBytesAfterCopy).to.be.equal(byteArrayLongerThan32Bytes);
+        });
+        it('should overwrite the leftmost len(source) bytes of dest if dest is larger than source', async () => {
+            const zeroedByteArrayLongerThan32Bytes = `0x${_.repeat('0', byteArrayLongerThan32Bytes.length * 2)}`;
+            const zeroedBytesAfterCopy = await libBytes.publicDeepCopyBytes.callAsync(
+                zeroedByteArrayLongerThan32Bytes,
+                byteArrayLongerThan32Bytes,
+            );
+            const copiedBytes = zeroedBytesAfterCopy.slice(0, byteArrayLongerThan32Bytes.length);
+            return expect(copiedBytes).to.be.equal(byteArrayLongerThan32Bytes);
+        });
+        it('should not overwrite the rightmost bytes of dest if dest is larger than source', async () => {
+            const zeroedByteArrayLongerThan32Bytes = `0x${_.repeat('0', byteArrayLongerThan32Bytes.length * 2)}`;
+            const zeroedBytesAfterCopy = await libBytes.publicDeepCopyBytes.callAsync(
+                zeroedByteArrayLongerThan32Bytes,
+                byteArrayLongerThan32Bytes,
+            );
+            const expectedNotCopiedBytes = zeroedByteArrayLongerThan32Bytes.slice(byteArrayLongerThan32Bytes.length);
+            const notCopiedBytes = zeroedBytesAfterCopy.slice(byteArrayLongerThan32Bytes.length);
+            return expect(notCopiedBytes).to.be.equal(expectedNotCopiedBytes);
+        });
+    });
+
     describe('readAddress', () => {
-        it('should successfully read address when the address takes up the whole array)', async () => {
+        it('should successfully read address when the address takes up the whole array', async () => {
             const byteArray = ethUtil.addHexPrefix(testAddress);
             const testAddressOffset = new BigNumber(0);
             const address = await libBytes.publicReadAddress.callAsync(byteArray, testAddressOffset);
             return expect(address).to.be.equal(testAddress);
         });
-
-        it('should successfully read address when it is offset in the array)', async () => {
+        it('should successfully read address when it is offset in the array', async () => {
             const addressByteArrayBuffer = ethUtil.toBuffer(testAddress);
             const prefixByteArrayBuffer = ethUtil.toBuffer('0xabcdef');
             const combinedByteArrayBuffer = Buffer.concat([prefixByteArrayBuffer, addressByteArrayBuffer]);
@@ -158,80 +220,145 @@ describe('LibBytes', () => {
             const address = await libBytes.publicReadAddress.callAsync(combinedByteArray, testAddressOffset);
             return expect(address).to.be.equal(testAddress);
         });
-
-        it('should fail if the byte array is too short to hold an address)', async () => {
+        it('should fail if the byte array is too short to hold an address', async () => {
             const shortByteArray = '0xabcdef';
             const offset = new BigNumber(0);
-            return expect(libBytes.publicReadAddress.callAsync(shortByteArray, offset)).to.be.rejectedWith(
-                constants.REVERT,
+            return expectRevertOrOtherErrorAsync(
+                libBytes.publicReadAddress.callAsync(shortByteArray, offset),
+                constants.LIB_BYTES_GREATER_OR_EQUAL_TO_20_LENGTH_REQUIRED,
             );
         });
-
-        it('should fail if the length between the offset and end of the byte array is too short to hold an address)', async () => {
-            const byteArray = ethUtil.addHexPrefix(testAddress);
+        it('should fail if the length between the offset and end of the byte array is too short to hold an address', async () => {
+            const byteArray = testAddress;
             const badOffset = new BigNumber(ethUtil.toBuffer(byteArray).byteLength);
-            return expect(libBytes.publicReadAddress.callAsync(byteArray, badOffset)).to.be.rejectedWith(
-                constants.REVERT,
+            return expectRevertOrOtherErrorAsync(
+                libBytes.publicReadAddress.callAsync(byteArray, badOffset),
+                constants.LIB_BYTES_GREATER_OR_EQUAL_TO_20_LENGTH_REQUIRED,
             );
         });
     });
 
-    /// @TODO Implement test cases for writeAddress. Test template below.
-    ///       Currently, the generated contract wrappers do not support this library's write methods.
-    /*
     describe('writeAddress', () => {
-        it('should successfully write address when the address takes up the whole array)', async () => {});
-        it('should successfully write address when it is offset in the array)', async () => {});
-        it('should fail if the byte array is too short to hold an address)', async () => {});
-        it('should fail if the length between the offset and end of the byte array is too short to hold an address)', async () => {});
+        it('should successfully write address when the address takes up the whole array', async () => {
+            const byteArray = testAddress;
+            const testAddressOffset = new BigNumber(0);
+            const newByteArray = await libBytes.publicWriteAddress.callAsync(
+                byteArray,
+                testAddressOffset,
+                testAddressB,
+            );
+            return expect(newByteArray).to.be.equal(testAddressB);
+        });
+        it('should successfully write address when it is offset in the array', async () => {
+            const addressByteArrayBuffer = ethUtil.toBuffer(testAddress);
+            const prefixByteArrayBuffer = ethUtil.toBuffer('0xabcdef');
+            const combinedByteArrayBuffer = Buffer.concat([prefixByteArrayBuffer, addressByteArrayBuffer]);
+            const combinedByteArray = ethUtil.bufferToHex(combinedByteArrayBuffer);
+            const testAddressOffset = new BigNumber(prefixByteArrayBuffer.byteLength);
+            const newByteArray = await libBytes.publicWriteAddress.callAsync(
+                combinedByteArray,
+                testAddressOffset,
+                testAddressB,
+            );
+            const newByteArrayBuffer = ethUtil.toBuffer(newByteArray);
+            const addressFromOffsetBuffer = newByteArrayBuffer.slice(prefixByteArrayBuffer.byteLength);
+            const addressFromOffset = ethUtil.addHexPrefix(ethUtil.bufferToHex(addressFromOffsetBuffer));
+            return expect(addressFromOffset).to.be.equal(testAddressB);
+        });
+        it('should fail if the byte array is too short to hold an address', async () => {
+            const offset = new BigNumber(0);
+            return expectRevertOrOtherErrorAsync(
+                libBytes.publicWriteAddress.callAsync(byteArrayShorterThan20Bytes, offset, testAddress),
+                constants.LIB_BYTES_GREATER_OR_EQUAL_TO_20_LENGTH_REQUIRED,
+            );
+        });
+        it('should fail if the length between the offset and end of the byte array is too short to hold an address', async () => {
+            const byteArray = byteArrayLongerThan32Bytes;
+            const badOffset = new BigNumber(ethUtil.toBuffer(byteArray).byteLength);
+            return expectRevertOrOtherErrorAsync(
+                libBytes.publicWriteAddress.callAsync(byteArray, badOffset, testAddress),
+                constants.LIB_BYTES_GREATER_OR_EQUAL_TO_20_LENGTH_REQUIRED,
+            );
+        });
     });
-    */
 
     describe('readBytes32', () => {
-        it('should successfully read bytes32 when the bytes32 takes up the whole array)', async () => {
+        it('should successfully read bytes32 when the bytes32 takes up the whole array', async () => {
             const testBytes32Offset = new BigNumber(0);
             const bytes32 = await libBytes.publicReadBytes32.callAsync(testBytes32, testBytes32Offset);
             return expect(bytes32).to.be.equal(testBytes32);
         });
-
         it('should successfully read bytes32 when it is offset in the array)', async () => {
             const bytes32ByteArrayBuffer = ethUtil.toBuffer(testBytes32);
             const prefixByteArrayBuffer = ethUtil.toBuffer('0xabcdef');
             const combinedByteArrayBuffer = Buffer.concat([prefixByteArrayBuffer, bytes32ByteArrayBuffer]);
             const combinedByteArray = ethUtil.bufferToHex(combinedByteArrayBuffer);
-            const testAddressOffset = new BigNumber(prefixByteArrayBuffer.byteLength);
-            const bytes32 = await libBytes.publicReadBytes32.callAsync(combinedByteArray, testAddressOffset);
+            const testBytes32Offset = new BigNumber(prefixByteArrayBuffer.byteLength);
+            const bytes32 = await libBytes.publicReadBytes32.callAsync(combinedByteArray, testBytes32Offset);
             return expect(bytes32).to.be.equal(testBytes32);
         });
-
-        it('should fail if the byte array is too short to hold a bytes32)', async () => {
+        it('should fail if the byte array is too short to hold a bytes32', async () => {
             const offset = new BigNumber(0);
-            return expect(libBytes.publicReadBytes32.callAsync(byteArrayShorterThan32Bytes, offset)).to.be.rejectedWith(
-                constants.REVERT,
+            return expectRevertOrOtherErrorAsync(
+                libBytes.publicReadBytes32.callAsync(byteArrayShorterThan32Bytes, offset),
+                constants.LIB_BYTES_GREATER_OR_EQUAL_TO_32_LENGTH_REQUIRED,
             );
         });
-
-        it('should fail if the length between the offset and end of the byte array is too short to hold a bytes32)', async () => {
+        it('should fail if the length between the offset and end of the byte array is too short to hold a bytes32', async () => {
             const badOffset = new BigNumber(ethUtil.toBuffer(testBytes32).byteLength);
-            return expect(libBytes.publicReadBytes32.callAsync(testBytes32, badOffset)).to.be.rejectedWith(
-                constants.REVERT,
+            return expectRevertOrOtherErrorAsync(
+                libBytes.publicReadBytes32.callAsync(testBytes32, badOffset),
+                constants.LIB_BYTES_GREATER_OR_EQUAL_TO_32_LENGTH_REQUIRED,
             );
         });
     });
 
-    /// @TODO Implement test cases for writeBytes32. Test template below.
-    ///       Currently, the generated contract wrappers do not support this library's write methods.
-    /*
     describe('writeBytes32', () => {
-        it('should successfully write bytes32 when the address takes up the whole array)', async () => {});
-        it('should successfully write bytes32 when it is offset in the array)', async () => {});
-        it('should fail if the byte array is too short to hold a bytes32)', async () => {});
-        it('should fail if the length between the offset and end of the byte array is too short to hold a bytes32)', async () => {});
+        it('should successfully write bytes32 when the address takes up the whole array', async () => {
+            const byteArray = testBytes32;
+            const testBytes32Offset = new BigNumber(0);
+            const newByteArray = await libBytes.publicWriteBytes32.callAsync(
+                byteArray,
+                testBytes32Offset,
+                testBytes32B,
+            );
+            return expect(newByteArray).to.be.equal(testBytes32B);
+        });
+        it('should successfully write bytes32 when it is offset in the array', async () => {
+            const bytes32ByteArrayBuffer = ethUtil.toBuffer(testBytes32);
+            const prefixByteArrayBuffer = ethUtil.toBuffer('0xabcdef');
+            const combinedByteArrayBuffer = Buffer.concat([prefixByteArrayBuffer, bytes32ByteArrayBuffer]);
+            const combinedByteArray = ethUtil.bufferToHex(combinedByteArrayBuffer);
+            const testBytes32Offset = new BigNumber(prefixByteArrayBuffer.byteLength);
+            const newByteArray = await libBytes.publicWriteBytes32.callAsync(
+                combinedByteArray,
+                testBytes32Offset,
+                testBytes32B,
+            );
+            const newByteArrayBuffer = ethUtil.toBuffer(newByteArray);
+            const bytes32FromOffsetBuffer = newByteArrayBuffer.slice(prefixByteArrayBuffer.byteLength);
+            const bytes32FromOffset = ethUtil.addHexPrefix(ethUtil.bufferToHex(bytes32FromOffsetBuffer));
+            return expect(bytes32FromOffset).to.be.equal(testBytes32B);
+        });
+        it('should fail if the byte array is too short to hold a bytes32', async () => {
+            const offset = new BigNumber(0);
+            return expectRevertOrOtherErrorAsync(
+                libBytes.publicWriteBytes32.callAsync(byteArrayShorterThan32Bytes, offset, testBytes32),
+                constants.LIB_BYTES_GREATER_OR_EQUAL_TO_32_LENGTH_REQUIRED,
+            );
+        });
+        it('should fail if the length between the offset and end of the byte array is too short to hold a bytes32', async () => {
+            const byteArray = byteArrayLongerThan32Bytes;
+            const badOffset = new BigNumber(ethUtil.toBuffer(byteArray).byteLength);
+            return expectRevertOrOtherErrorAsync(
+                libBytes.publicWriteBytes32.callAsync(byteArray, badOffset, testBytes32),
+                constants.LIB_BYTES_GREATER_OR_EQUAL_TO_32_LENGTH_REQUIRED,
+            );
+        });
     });
-    */
 
     describe('readUint256', () => {
-        it('should successfully read uint256 when the uint256 takes up the whole array)', async () => {
+        it('should successfully read uint256 when the uint256 takes up the whole array', async () => {
             const formattedTestUint256 = new BN(testUint256.toString(10));
             const testUint256AsBuffer = ethUtil.toBuffer(formattedTestUint256);
             const byteArray = ethUtil.bufferToHex(testUint256AsBuffer);
@@ -239,8 +366,7 @@ describe('LibBytes', () => {
             const uint256 = await libBytes.publicReadUint256.callAsync(byteArray, testUint256Offset);
             return expect(uint256).to.bignumber.equal(testUint256);
         });
-
-        it('should successfully read uint256 when it is offset in the array)', async () => {
+        it('should successfully read uint256 when it is offset in the array', async () => {
             const prefixByteArrayBuffer = ethUtil.toBuffer('0xabcdef');
             const formattedTestUint256 = new BN(testUint256.toString(10));
             const testUint256AsBuffer = ethUtil.toBuffer(formattedTestUint256);
@@ -250,41 +376,80 @@ describe('LibBytes', () => {
             const uint256 = await libBytes.publicReadUint256.callAsync(combinedByteArray, testUint256Offset);
             return expect(uint256).to.bignumber.equal(testUint256);
         });
-
-        it('should fail if the byte array is too short to hold a uint256)', async () => {
+        it('should fail if the byte array is too short to hold a uint256', async () => {
             const offset = new BigNumber(0);
-            return expect(libBytes.publicReadUint256.callAsync(byteArrayShorterThan32Bytes, offset)).to.be.rejectedWith(
-                constants.REVERT,
+            return expectRevertOrOtherErrorAsync(
+                libBytes.publicReadUint256.callAsync(byteArrayShorterThan32Bytes, offset),
+                constants.LIB_BYTES_GREATER_OR_EQUAL_TO_32_LENGTH_REQUIRED,
             );
         });
-
-        it('should fail if the length between the offset and end of the byte array is too short to hold a uint256)', async () => {
+        it('should fail if the length between the offset and end of the byte array is too short to hold a uint256', async () => {
             const formattedTestUint256 = new BN(testUint256.toString(10));
             const testUint256AsBuffer = ethUtil.toBuffer(formattedTestUint256);
             const byteArray = ethUtil.bufferToHex(testUint256AsBuffer);
             const badOffset = new BigNumber(testUint256AsBuffer.byteLength);
-            return expect(libBytes.publicReadUint256.callAsync(byteArray, badOffset)).to.be.rejectedWith(
-                constants.REVERT,
+            return expectRevertOrOtherErrorAsync(
+                libBytes.publicReadUint256.callAsync(byteArray, badOffset),
+                constants.LIB_BYTES_GREATER_OR_EQUAL_TO_32_LENGTH_REQUIRED,
             );
         });
     });
 
-    /// @TODO Implement test cases for writeUint256. Test template below.
-    ///       Currently, the generated contract wrappers do not support this library's write methods.
-    /*
     describe('writeUint256', () => {
-        it('should successfully write uint256 when the address takes up the whole array)', async () => {});
-        it('should successfully write uint256 when it is offset in the array)', async () => {});
-        it('should fail if the byte array is too short to hold a uint256)', async () => {});
-        it('should fail if the length between the offset and end of the byte array is too short to hold a uint256)', async () => {});
+        it('should successfully write uint256 when the address takes up the whole array', async () => {
+            const byteArray = testBytes32;
+            const testUint256Offset = new BigNumber(0);
+            const newByteArray = await libBytes.publicWriteUint256.callAsync(
+                byteArray,
+                testUint256Offset,
+                testUint256B,
+            );
+            const newByteArrayAsUint256 = new BigNumber(newByteArray, 16);
+            return expect(newByteArrayAsUint256).to.be.bignumber.equal(testUint256B);
+        });
+        it('should successfully write uint256 when it is offset in the array', async () => {
+            const bytes32ByteArrayBuffer = ethUtil.toBuffer(testBytes32);
+            const prefixByteArrayBuffer = ethUtil.toBuffer('0xabcdef');
+            const combinedByteArrayBuffer = Buffer.concat([prefixByteArrayBuffer, bytes32ByteArrayBuffer]);
+            const combinedByteArray = ethUtil.bufferToHex(combinedByteArrayBuffer);
+            const testUint256Offset = new BigNumber(prefixByteArrayBuffer.byteLength);
+            const newByteArray = await libBytes.publicWriteUint256.callAsync(
+                combinedByteArray,
+                testUint256Offset,
+                testUint256B,
+            );
+            const newByteArrayBuffer = ethUtil.toBuffer(newByteArray);
+            const uint256FromOffsetBuffer = newByteArrayBuffer.slice(prefixByteArrayBuffer.byteLength);
+            const uint256FromOffset = new BigNumber(
+                ethUtil.addHexPrefix(ethUtil.bufferToHex(uint256FromOffsetBuffer)),
+                16,
+            );
+            return expect(uint256FromOffset).to.be.bignumber.equal(testUint256B);
+        });
+        it('should fail if the byte array is too short to hold a uint256', async () => {
+            const offset = new BigNumber(0);
+            return expectRevertOrOtherErrorAsync(
+                libBytes.publicWriteUint256.callAsync(byteArrayShorterThan32Bytes, offset, testUint256),
+                constants.LIB_BYTES_GREATER_OR_EQUAL_TO_32_LENGTH_REQUIRED,
+            );
+        });
+        it('should fail if the length between the offset and end of the byte array is too short to hold a uint256', async () => {
+            const byteArray = byteArrayLongerThan32Bytes;
+            const badOffset = new BigNumber(ethUtil.toBuffer(byteArray).byteLength);
+            return expectRevertOrOtherErrorAsync(
+                libBytes.publicWriteUint256.callAsync(byteArray, badOffset, testUint256),
+                constants.LIB_BYTES_GREATER_OR_EQUAL_TO_32_LENGTH_REQUIRED,
+            );
+        });
     });
-    */
 
     describe('readFirst4', () => {
+        // AssertionError: expected promise to be rejected with an error including 'revert' but it was fulfilled with '0x08c379a0'
         it('should revert if byte array has a length < 4', async () => {
             const byteArrayLessThan4Bytes = '0x010101';
-            return expect(libBytes.publicReadFirst4.callAsync(byteArrayLessThan4Bytes)).to.be.rejectedWith(
-                constants.REVERT,
+            return expectRevertOrOtherErrorAsync(
+                libBytes.publicReadFirst4.callAsync(byteArrayLessThan4Bytes),
+                constants.LIB_BYTES_GREATER_OR_EQUAL_TO_4_LENGTH_REQUIRED,
             );
         });
         it('should return the first 4 bytes of a byte array of arbitrary length', async () => {
@@ -293,4 +458,164 @@ describe('LibBytes', () => {
             expect(first4Bytes).to.equal(expectedFirst4Bytes);
         });
     });
+
+    describe('readBytes', () => {
+        it('should successfully read short, nested array of bytes when it takes up the whole array', async () => {
+            const testBytesOffset = new BigNumber(0);
+            const bytes = await libBytes.publicReadBytes.callAsync(shortTestBytes, testBytesOffset);
+            return expect(bytes).to.be.equal(shortData);
+        });
+        it('should successfully read short, nested array of bytes when it is offset in the array', async () => {
+            const prefixByteArrayBuffer = ethUtil.toBuffer('0xabcdef');
+            const combinedByteArrayBuffer = Buffer.concat([prefixByteArrayBuffer, shortTestBytesAsBuffer]);
+            const combinedByteArray = ethUtil.bufferToHex(combinedByteArrayBuffer);
+            const testUint256Offset = new BigNumber(prefixByteArrayBuffer.byteLength);
+            const bytes = await libBytes.publicReadBytes.callAsync(combinedByteArray, testUint256Offset);
+            return expect(bytes).to.be.equal(shortData);
+        });
+        it('should successfully read a nested array of bytes - one word in length - when it takes up the whole array', async () => {
+            const testBytesOffset = new BigNumber(0);
+            const bytes = await libBytes.publicReadBytes.callAsync(wordOfTestBytes, testBytesOffset);
+            return expect(bytes).to.be.equal(wordOfData);
+        });
+        it('should successfully read a nested array of bytes - one word in length - when it is offset in the array', async () => {
+            const prefixByteArrayBuffer = ethUtil.toBuffer('0xabcdef');
+            const combinedByteArrayBuffer = Buffer.concat([prefixByteArrayBuffer, wordOfTestBytesAsBuffer]);
+            const combinedByteArray = ethUtil.bufferToHex(combinedByteArrayBuffer);
+            const testUint256Offset = new BigNumber(prefixByteArrayBuffer.byteLength);
+            const bytes = await libBytes.publicReadBytes.callAsync(combinedByteArray, testUint256Offset);
+            return expect(bytes).to.be.equal(wordOfData);
+        });
+        it('should successfully read long, nested array of bytes when it takes up the whole array', async () => {
+            const testBytesOffset = new BigNumber(0);
+            const bytes = await libBytes.publicReadBytes.callAsync(longTestBytes, testBytesOffset);
+            return expect(bytes).to.be.equal(longData);
+        });
+        it('should successfully read long, nested array of bytes when it is offset in the array', async () => {
+            const prefixByteArrayBuffer = ethUtil.toBuffer('0xabcdef');
+            const combinedByteArrayBuffer = Buffer.concat([prefixByteArrayBuffer, longTestBytesAsBuffer]);
+            const combinedByteArray = ethUtil.bufferToHex(combinedByteArrayBuffer);
+            const testUint256Offset = new BigNumber(prefixByteArrayBuffer.byteLength);
+            const bytes = await libBytes.publicReadBytes.callAsync(combinedByteArray, testUint256Offset);
+            return expect(bytes).to.be.equal(longData);
+        });
+        it('should fail if the byte array is too short to hold the length of a nested byte array', async () => {
+            // The length of the nested array is 32 bytes. By storing less than 32 bytes, a length cannot be read.
+            const offset = new BigNumber(0);
+            return expectRevertOrOtherErrorAsync(
+                libBytes.publicReadBytes.callAsync(byteArrayShorterThan32Bytes, offset),
+                constants.LIB_BYTES_GREATER_OR_EQUAL_TO_32_LENGTH_REQUIRED,
+            );
+        });
+        it('should fail if we store a nested byte array length, without a nested byte array', async () => {
+            const offset = new BigNumber(0);
+            return expectRevertOrOtherErrorAsync(
+                libBytes.publicReadBytes.callAsync(testBytes32, offset),
+                constants.LIB_BYTES_GREATER_OR_EQUAL_TO_NESTED_BYTES_LENGTH_REQUIRED,
+            );
+        });
+        it('should fail if the length between the offset and end of the byte array is too short to hold the length of a nested byte array', async () => {
+            const badOffset = new BigNumber(ethUtil.toBuffer(byteArrayShorterThan32Bytes).byteLength);
+            return expectRevertOrOtherErrorAsync(
+                libBytes.publicReadBytes.callAsync(byteArrayShorterThan32Bytes, badOffset),
+                constants.LIB_BYTES_GREATER_OR_EQUAL_TO_32_LENGTH_REQUIRED,
+            );
+        });
+        it('should fail if the length between the offset and end of the byte array is too short to hold the nested byte array', async () => {
+            const badOffset = new BigNumber(ethUtil.toBuffer(testBytes32).byteLength);
+            return expectRevertOrOtherErrorAsync(
+                libBytes.publicReadBytes.callAsync(testBytes32, badOffset),
+                constants.LIB_BYTES_GREATER_OR_EQUAL_TO_32_LENGTH_REQUIRED,
+            );
+        });
+    });
+
+    describe('writeBytes', () => {
+        it('should successfully write short, nested array of bytes when it takes up the whole array)', async () => {
+            const testBytesOffset = new BigNumber(0);
+            const emptyByteArray = ethUtil.bufferToHex(new Buffer(shortTestBytesAsBuffer.byteLength));
+            const bytesWritten = await libBytes.publicWriteBytes.callAsync(emptyByteArray, testBytesOffset, shortData);
+            const bytesRead = await libBytes.publicReadBytes.callAsync(bytesWritten, testBytesOffset);
+            return expect(bytesRead).to.be.equal(shortData);
+        });
+        it('should successfully write short, nested array of bytes when it is offset in the array', async () => {
+            // Write a prefix to the array
+            const prefixData = '0xabcdef';
+            const prefixDataAsBuffer = ethUtil.toBuffer(prefixData);
+            const prefixOffset = new BigNumber(0);
+            const emptyByteArray = ethUtil.bufferToHex(
+                new Buffer(prefixDataAsBuffer.byteLength + shortTestBytesAsBuffer.byteLength),
+            );
+            let bytesWritten = await libBytes.publicWriteBytes.callAsync(emptyByteArray, prefixOffset, prefixData);
+            // Write data after prefix
+            const testBytesOffset = new BigNumber(prefixDataAsBuffer.byteLength);
+            bytesWritten = await libBytes.publicWriteBytes.callAsync(bytesWritten, testBytesOffset, shortData);
+            // Read data after prefix and validate
+            const bytes = await libBytes.publicReadBytes.callAsync(bytesWritten, testBytesOffset);
+            return expect(bytes).to.be.equal(shortData);
+        });
+        it('should successfully write a nested array of bytes - one word in length - when it takes up the whole array', async () => {
+            const testBytesOffset = new BigNumber(0);
+            const emptyByteArray = ethUtil.bufferToHex(new Buffer(wordOfTestBytesAsBuffer.byteLength));
+            const bytesWritten = await libBytes.publicWriteBytes.callAsync(emptyByteArray, testBytesOffset, wordOfData);
+            const bytesRead = await libBytes.publicReadBytes.callAsync(bytesWritten, testBytesOffset);
+            return expect(bytesRead).to.be.equal(wordOfData);
+        });
+        it('should successfully write a nested array of bytes - one word in length - when it is offset in the array', async () => {
+            // Write a prefix to the array
+            const prefixData = '0xabcdef';
+            const prefixDataAsBuffer = ethUtil.toBuffer(prefixData);
+            const prefixOffset = new BigNumber(0);
+            const emptyByteArray = ethUtil.bufferToHex(
+                new Buffer(prefixDataAsBuffer.byteLength + wordOfTestBytesAsBuffer.byteLength),
+            );
+            let bytesWritten = await libBytes.publicWriteBytes.callAsync(emptyByteArray, prefixOffset, prefixData);
+            // Write data after prefix
+            const testBytesOffset = new BigNumber(prefixDataAsBuffer.byteLength);
+            bytesWritten = await libBytes.publicWriteBytes.callAsync(bytesWritten, testBytesOffset, wordOfData);
+            // Read data after prefix and validate
+            const bytes = await libBytes.publicReadBytes.callAsync(bytesWritten, testBytesOffset);
+            return expect(bytes).to.be.equal(wordOfData);
+        });
+        it('should successfully write a long, nested bytes when it takes up the whole array', async () => {
+            const testBytesOffset = new BigNumber(0);
+            const emptyByteArray = ethUtil.bufferToHex(new Buffer(longTestBytesAsBuffer.byteLength));
+            const bytesWritten = await libBytes.publicWriteBytes.callAsync(emptyByteArray, testBytesOffset, longData);
+            const bytesRead = await libBytes.publicReadBytes.callAsync(bytesWritten, testBytesOffset);
+            return expect(bytesRead).to.be.equal(longData);
+        });
+        it('should successfully write long, nested array of bytes when it is offset in the array', async () => {
+            // Write a prefix to the array
+            const prefixData = '0xabcdef';
+            const prefixDataAsBuffer = ethUtil.toBuffer(prefixData);
+            const prefixOffset = new BigNumber(0);
+            const emptyByteArray = ethUtil.bufferToHex(
+                new Buffer(prefixDataAsBuffer.byteLength + longTestBytesAsBuffer.byteLength),
+            );
+            let bytesWritten = await libBytes.publicWriteBytes.callAsync(emptyByteArray, prefixOffset, prefixData);
+            // Write data after prefix
+            const testBytesOffset = new BigNumber(prefixDataAsBuffer.byteLength);
+            bytesWritten = await libBytes.publicWriteBytes.callAsync(bytesWritten, testBytesOffset, longData);
+            // Read data after prefix and validate
+            const bytes = await libBytes.publicReadBytes.callAsync(bytesWritten, testBytesOffset);
+            return expect(bytes).to.be.equal(longData);
+        });
+        it('should fail if the byte array is too short to hold the length of a nested byte array', async () => {
+            const offset = new BigNumber(0);
+            const emptyByteArray = ethUtil.bufferToHex(new Buffer(1));
+            return expectRevertOrOtherErrorAsync(
+                libBytes.publicWriteBytes.callAsync(emptyByteArray, offset, longData),
+                constants.LIB_BYTES_GREATER_OR_EQUAL_TO_NESTED_BYTES_LENGTH_REQUIRED,
+            );
+        });
+        it('should fail if the length between the offset and end of the byte array is too short to hold the length of a nested byte array)', async () => {
+            const emptyByteArray = ethUtil.bufferToHex(new Buffer(shortTestBytesAsBuffer.byteLength));
+            const badOffset = new BigNumber(ethUtil.toBuffer(shortTestBytesAsBuffer).byteLength);
+            return expectRevertOrOtherErrorAsync(
+                libBytes.publicWriteBytes.callAsync(emptyByteArray, badOffset, shortData),
+                constants.LIB_BYTES_GREATER_OR_EQUAL_TO_NESTED_BYTES_LENGTH_REQUIRED,
+            );
+        });
+    });
 });
+// tslint:disable:max-file-line-count
diff --git a/packages/contracts/test/libraries/lib_mem.ts b/packages/contracts/test/libraries/lib_mem.ts
new file mode 100644
index 000000000..00f7c4d8b
--- /dev/null
+++ b/packages/contracts/test/libraries/lib_mem.ts
@@ -0,0 +1,190 @@
+import { BigNumber } from '@0xproject/utils';
+import * as chai from 'chai';
+
+import { TestLibMemContract } from '../../src/generated_contract_wrappers/test_lib_mem';
+import { artifacts } from '../../src/utils/artifacts';
+import { chaiSetup } from '../../src/utils/chai_setup';
+import { provider, txDefaults } from '../../src/utils/web3_wrapper';
+
+chaiSetup.configure();
+const expect = chai.expect;
+
+// BUG: Ideally we would use Buffer.from(memory).toString('hex')
+// https://github.com/Microsoft/TypeScript/issues/23155
+const toHex = (buf: Uint8Array): string => buf.reduce((a, v) => a + ('00' + v.toString(16)).slice(-2), '0x');
+
+const fromHex = (str: string): Uint8Array => Uint8Array.from(Buffer.from(str.slice(2), 'hex'));
+
+describe('LibMem', () => {
+    let testLibMem: TestLibMemContract;
+
+    before(async () => {
+        // Deploy TestLibMem
+        testLibMem = await TestLibMemContract.deployFrom0xArtifactAsync(artifacts.TestLibMem, provider, txDefaults);
+    });
+
+    describe('memCopy', () => {
+        // Create memory 0x000102...FF
+        const memSize = 256;
+        const memory = new Uint8Array(memSize).map((_, i) => i);
+        const memHex = toHex(memory);
+
+        // Reference implementation to test against
+        const refMemcpy = (_mem: Uint8Array, dest: number, source: number, length: number): Uint8Array =>
+            Uint8Array.from(memory).copyWithin(dest, source, source + length);
+
+        // Test vectors: destination, source, length, job description
+        type Tests = Array<[number, number, number, string]>;
+
+        const test = (tests: Tests) =>
+            tests.forEach(([dest, source, length, job]) =>
+                it(job, async () => {
+                    const expected = refMemcpy(memory, dest, source, length);
+                    const resultStr = await testLibMem.testMemcpy.callAsync(
+                        memHex,
+                        new BigNumber(dest),
+                        new BigNumber(source),
+                        new BigNumber(length),
+                    );
+                    const result = fromHex(resultStr);
+                    expect(result).to.deep.equal(expected);
+                }),
+            );
+
+        test([[0, 0, 0, 'copies zero bytes with overlap']]);
+
+        describe('copies forward', () =>
+            test([
+                [128, 0, 0, 'zero bytes'],
+                [128, 0, 1, 'one byte'],
+                [128, 0, 11, 'eleven bytes'],
+                [128, 0, 31, 'thirty-one bytes'],
+                [128, 0, 32, 'one word'],
+                [128, 0, 64, 'two words'],
+                [128, 0, 96, 'three words'],
+                [128, 0, 33, 'one word and one byte'],
+                [128, 0, 72, 'two words and eight bytes'],
+                [128, 0, 100, 'three words and four bytes'],
+            ]));
+
+        describe('copies forward within one word', () =>
+            test([
+                [16, 0, 0, 'zero bytes'],
+                [16, 0, 1, 'one byte'],
+                [16, 0, 11, 'eleven bytes'],
+                [16, 0, 16, 'sixteen bytes'],
+            ]));
+
+        describe('copies forward with one byte overlap', () =>
+            test([
+                [0, 0, 1, 'one byte'],
+                [10, 0, 11, 'eleven bytes'],
+                [30, 0, 31, 'thirty-one bytes'],
+                [31, 0, 32, 'one word'],
+                [32, 0, 33, 'one word and one byte'],
+                [71, 0, 72, 'two words and eight bytes'],
+                [99, 0, 100, 'three words and four bytes'],
+            ]));
+
+        describe('copies forward with thirty-one bytes overlap', () =>
+            test([
+                [0, 0, 31, 'thirty-one bytes'],
+                [1, 0, 32, 'one word'],
+                [2, 0, 33, 'one word and one byte'],
+                [41, 0, 72, 'two words and eight bytes'],
+                [69, 0, 100, 'three words and four bytes'],
+            ]));
+
+        describe('copies forward with one word overlap', () =>
+            test([
+                [0, 0, 32, 'one word'],
+                [1, 0, 33, 'one word and one byte'],
+                [41, 0, 72, 'two words and eight bytes'],
+                [69, 0, 100, 'three words and four bytes'],
+            ]));
+
+        describe('copies forward with one word and one byte overlap', () =>
+            test([
+                [0, 0, 33, 'one word and one byte'],
+                [40, 0, 72, 'two words and eight bytes'],
+                [68, 0, 100, 'three words and four bytes'],
+            ]));
+
+        describe('copies forward with two words overlap', () =>
+            test([
+                [0, 0, 64, 'two words'],
+                [8, 0, 72, 'two words and eight bytes'],
+                [36, 0, 100, 'three words and four bytes'],
+            ]));
+
+        describe('copies forward within one word and one byte overlap', () =>
+            test([[0, 0, 1, 'one byte'], [10, 0, 11, 'eleven bytes'], [15, 0, 16, 'sixteen bytes']]));
+
+        describe('copies backward', () =>
+            test([
+                [0, 128, 0, 'zero bytes'],
+                [0, 128, 1, 'one byte'],
+                [0, 128, 11, 'eleven bytes'],
+                [0, 128, 31, 'thirty-one bytes'],
+                [0, 128, 32, 'one word'],
+                [0, 128, 64, 'two words'],
+                [0, 128, 96, 'three words'],
+                [0, 128, 33, 'one word and one byte'],
+                [0, 128, 72, 'two words and eight bytes'],
+                [0, 128, 100, 'three words and four bytes'],
+            ]));
+
+        describe('copies backward within one word', () =>
+            test([
+                [0, 16, 0, 'zero bytes'],
+                [0, 16, 1, 'one byte'],
+                [0, 16, 11, 'eleven bytes'],
+                [0, 16, 16, 'sixteen bytes'],
+            ]));
+
+        describe('copies backward with one byte overlap', () =>
+            test([
+                [0, 0, 1, 'one byte'],
+                [0, 10, 11, 'eleven bytes'],
+                [0, 30, 31, 'thirty-one bytes'],
+                [0, 31, 32, 'one word'],
+                [0, 32, 33, 'one word and one byte'],
+                [0, 71, 72, 'two words and eight bytes'],
+                [0, 99, 100, 'three words and four bytes'],
+            ]));
+
+        describe('copies backward with thirty-one bytes overlap', () =>
+            test([
+                [0, 0, 31, 'thirty-one bytes'],
+                [0, 1, 32, 'one word'],
+                [0, 2, 33, 'one word and one byte'],
+                [0, 41, 72, 'two words and eight bytes'],
+                [0, 69, 100, 'three words and four bytes'],
+            ]));
+
+        describe('copies backward with one word overlap', () =>
+            test([
+                [0, 0, 32, 'one word'],
+                [0, 1, 33, 'one word and one byte'],
+                [0, 41, 72, 'two words and eight bytes'],
+                [0, 69, 100, 'three words and four bytes'],
+            ]));
+
+        describe('copies backward with one word and one byte overlap', () =>
+            test([
+                [0, 0, 33, 'one word and one byte'],
+                [0, 40, 72, 'two words and eight bytes'],
+                [0, 68, 100, 'three words and four bytes'],
+            ]));
+
+        describe('copies backward with two words overlap', () =>
+            test([
+                [0, 0, 64, 'two words'],
+                [0, 8, 72, 'two words and eight bytes'],
+                [0, 36, 100, 'three words and four bytes'],
+            ]));
+
+        describe('copies forward within one word and one byte overlap', () =>
+            test([[0, 0, 1, 'one byte'], [0, 10, 11, 'eleven bytes'], [0, 15, 16, 'sixteen bytes']]));
+    });
+});
diff --git a/packages/contracts/test/multi_sig_with_time_lock.ts b/packages/contracts/test/multi_sig_with_time_lock.ts
index 1302d0fa0..f630743e1 100644
--- a/packages/contracts/test/multi_sig_with_time_lock.ts
+++ b/packages/contracts/test/multi_sig_with_time_lock.ts
@@ -1,26 +1,25 @@
-import { BlockchainLifecycle, web3Factory } from '@0xproject/dev-utils';
+import { BlockchainLifecycle } from '@0xproject/dev-utils';
 import { BigNumber } from '@0xproject/utils';
-import { Web3Wrapper } from '@0xproject/web3-wrapper';
 import * as chai from 'chai';
 import { LogWithDecodedArgs } from 'ethereum-types';
-import * as _ from 'lodash';
 import 'make-promises-safe';
-import * as Web3 from 'web3';
 
 import {
     MultiSigWalletWithTimeLockContract,
     SubmissionContractEventArgs,
-} from '../src/contract_wrappers/generated/multi_sig_wallet_with_time_lock';
+} 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';
 
 chaiSetup.configure();
 const expect = chai.expect;
 const blockchainLifecycle = new BlockchainLifecycle(web3Wrapper);
-
+// tslint:disable:no-unnecessary-type-assertion
 describe('MultiSigWalletWithTimeLock', () => {
     let owners: string[];
     const REQUIRED_APPROVALS = new BigNumber(2);
@@ -69,9 +68,9 @@ describe('MultiSigWalletWithTimeLock', () => {
             });
 
             it('should throw when not called by wallet', async () => {
-                return expect(
+                return expectRevertOrAlwaysFailingTransactionAsync(
                     multiSig.changeTimeLock.sendTransactionAsync(SECONDS_TIME_LOCKED, { from: owners[0] }),
-                ).to.be.rejectedWith(constants.REVERT);
+                );
             });
 
             it('should throw without enough confirmations', async () => {
@@ -80,10 +79,9 @@ describe('MultiSigWalletWithTimeLock', () => {
                 const res = await multiSigWrapper.submitTransactionAsync(destination, changeTimeLockData, owners[0]);
                 const log = res.logs[0] as LogWithDecodedArgs<SubmissionContractEventArgs>;
                 const txId = log.args.transactionId;
-
-                return expect(
+                return expectRevertOrAlwaysFailingTransactionAsync(
                     multiSig.executeTransaction.sendTransactionAsync(txId, { from: owners[0] }),
-                ).to.be.rejectedWith(constants.REVERT);
+                );
             });
 
             it('should set confirmation time with enough confirmations', async () => {
@@ -148,14 +146,15 @@ describe('MultiSigWalletWithTimeLock', () => {
                 txId = log.args.transactionId;
                 await multiSigWrapper.confirmTransactionAsync(txId, owners[1]);
             });
+
             it('should throw if it has enough confirmations but is not past the time lock', async () => {
-                return expect(
+                return expectRevertOrAlwaysFailingTransactionAsync(
                     multiSig.executeTransaction.sendTransactionAsync(txId, { from: owners[0] }),
-                ).to.be.rejectedWith(constants.REVERT);
+                );
             });
 
             it('should execute if it has enough confirmations and is past the time lock', async () => {
-                await web3Wrapper.increaseTimeAsync(SECONDS_TIME_LOCKED.toNumber());
+                await increaseTimeAndMineBlockAsync(SECONDS_TIME_LOCKED.toNumber());
                 await web3Wrapper.awaitTransactionSuccessAsync(
                     await multiSig.executeTransaction.sendTransactionAsync(txId, { from: owners[0] }),
                     constants.AWAIT_TRANSACTION_MINED_MS,
@@ -167,3 +166,4 @@ describe('MultiSigWalletWithTimeLock', () => {
         });
     });
 });
+// tslint:enable:no-unnecessary-type-assertion
diff --git a/packages/contracts/test/token_registry.ts b/packages/contracts/test/token_registry.ts
index 64caac387..f368fd73d 100644
--- a/packages/contracts/test/token_registry.ts
+++ b/packages/contracts/test/token_registry.ts
@@ -1,14 +1,13 @@
-import { BlockchainLifecycle, devConstants, web3Factory } from '@0xproject/dev-utils';
+import { BlockchainLifecycle } from '@0xproject/dev-utils';
 import { BigNumber, NULL_BYTES } from '@0xproject/utils';
-import { Web3Wrapper } from '@0xproject/web3-wrapper';
 import * as chai from 'chai';
 import ethUtil = require('ethereumjs-util');
 import * as _ from 'lodash';
 import 'make-promises-safe';
-import * as Web3 from 'web3';
 
-import { TokenRegistryContract } from '../src/contract_wrappers/generated/token_registry';
+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';
@@ -76,7 +75,7 @@ describe('TokenRegistry', () => {
 
     describe('addToken', () => {
         it('should throw when not called by owner', async () => {
-            return expect(tokenRegWrapper.addTokenAsync(token1, notOwner)).to.be.rejectedWith(constants.REVERT);
+            return expectRevertOrAlwaysFailingTransactionAsync(tokenRegWrapper.addTokenAsync(token1, notOwner));
         });
 
         it('should add token metadata when called by owner', async () => {
@@ -88,19 +87,19 @@ describe('TokenRegistry', () => {
         it('should throw if token already exists', async () => {
             await tokenRegWrapper.addTokenAsync(token1, owner);
 
-            return expect(tokenRegWrapper.addTokenAsync(token1, owner)).to.be.rejectedWith(constants.REVERT);
+            return expectRevertOrAlwaysFailingTransactionAsync(tokenRegWrapper.addTokenAsync(token1, owner));
         });
 
         it('should throw if token address is null', async () => {
-            return expect(tokenRegWrapper.addTokenAsync(nullToken, owner)).to.be.rejectedWith(constants.REVERT);
+            return expectRevertOrAlwaysFailingTransactionAsync(tokenRegWrapper.addTokenAsync(nullToken, owner));
         });
 
         it('should throw if name already exists', async () => {
             await tokenRegWrapper.addTokenAsync(token1, owner);
             const duplicateNameToken = _.assign({}, token2, { name: token1.name });
 
-            return expect(tokenRegWrapper.addTokenAsync(duplicateNameToken, owner)).to.be.rejectedWith(
-                constants.REVERT,
+            return expectRevertOrAlwaysFailingTransactionAsync(
+                tokenRegWrapper.addTokenAsync(duplicateNameToken, owner),
             );
         });
 
@@ -110,8 +109,8 @@ describe('TokenRegistry', () => {
                 symbol: token1.symbol,
             });
 
-            return expect(tokenRegWrapper.addTokenAsync(duplicateSymbolToken, owner)).to.be.rejectedWith(
-                constants.REVERT,
+            return expectRevertOrAlwaysFailingTransactionAsync(
+                tokenRegWrapper.addTokenAsync(duplicateSymbolToken, owner),
             );
         });
     });
@@ -137,9 +136,9 @@ describe('TokenRegistry', () => {
 
         describe('setTokenName', () => {
             it('should throw when not called by owner', async () => {
-                return expect(
+                return expectRevertOrAlwaysFailingTransactionAsync(
                     tokenReg.setTokenName.sendTransactionAsync(token1.address, token2.name, { from: notOwner }),
-                ).to.be.rejectedWith(constants.REVERT);
+                );
             });
 
             it('should change the token name when called by owner', async () => {
@@ -163,25 +162,25 @@ describe('TokenRegistry', () => {
             it('should throw if the name already exists', async () => {
                 await tokenRegWrapper.addTokenAsync(token2, owner);
 
-                return expect(
+                return expectRevertOrAlwaysFailingTransactionAsync(
                     tokenReg.setTokenName.sendTransactionAsync(token1.address, token2.name, { from: owner }),
-                ).to.be.rejectedWith(constants.REVERT);
+                );
             });
 
             it('should throw if token does not exist', async () => {
-                return expect(
+                return expectRevertOrAlwaysFailingTransactionAsync(
                     tokenReg.setTokenName.sendTransactionAsync(nullToken.address, token2.name, { from: owner }),
-                ).to.be.rejectedWith(constants.REVERT);
+                );
             });
         });
 
         describe('setTokenSymbol', () => {
             it('should throw when not called by owner', async () => {
-                return expect(
+                return expectRevertOrAlwaysFailingTransactionAsync(
                     tokenReg.setTokenSymbol.sendTransactionAsync(token1.address, token2.symbol, {
                         from: notOwner,
                     }),
-                ).to.be.rejectedWith(constants.REVERT);
+                );
             });
 
             it('should change the token symbol when called by owner', async () => {
@@ -203,28 +202,28 @@ describe('TokenRegistry', () => {
             it('should throw if the symbol already exists', async () => {
                 await tokenRegWrapper.addTokenAsync(token2, owner);
 
-                return expect(
+                return expectRevertOrAlwaysFailingTransactionAsync(
                     tokenReg.setTokenSymbol.sendTransactionAsync(token1.address, token2.symbol, {
                         from: owner,
                     }),
-                ).to.be.rejectedWith(constants.REVERT);
+                );
             });
 
             it('should throw if token does not exist', async () => {
-                return expect(
+                return expectRevertOrAlwaysFailingTransactionAsync(
                     tokenReg.setTokenSymbol.sendTransactionAsync(nullToken.address, token2.symbol, {
                         from: owner,
                     }),
-                ).to.be.rejectedWith(constants.REVERT);
+                );
             });
         });
 
         describe('removeToken', () => {
             it('should throw if not called by owner', async () => {
                 const index = new BigNumber(0);
-                return expect(
+                return expectRevertOrAlwaysFailingTransactionAsync(
                     tokenReg.removeToken.sendTransactionAsync(token1.address, index, { from: notOwner }),
-                ).to.be.rejectedWith(constants.REVERT);
+                );
             });
 
             it('should remove token metadata when called by owner', async () => {
@@ -241,17 +240,17 @@ describe('TokenRegistry', () => {
 
             it('should throw if token does not exist', async () => {
                 const index = new BigNumber(0);
-                return expect(
+                return expectRevertOrAlwaysFailingTransactionAsync(
                     tokenReg.removeToken.sendTransactionAsync(nullToken.address, index, { from: owner }),
-                ).to.be.rejectedWith(constants.REVERT);
+                );
             });
 
             it('should throw if token at given index does not match address', async () => {
                 await tokenRegWrapper.addTokenAsync(token2, owner);
                 const incorrectIndex = new BigNumber(0);
-                return expect(
+                return expectRevertOrAlwaysFailingTransactionAsync(
                     tokenReg.removeToken.sendTransactionAsync(token2.address, incorrectIndex, { from: owner }),
-                ).to.be.rejectedWith(constants.REVERT);
+                );
             });
         });
     });
diff --git a/packages/contracts/test/tutorials/arbitrage.ts b/packages/contracts/test/tutorials/arbitrage.ts
index df01f31bb..32fcedb43 100644
--- a/packages/contracts/test/tutorials/arbitrage.ts
+++ b/packages/contracts/test/tutorials/arbitrage.ts
@@ -8,12 +8,12 @@
 // import ethUtil = require('ethereumjs-util');
 // import * as Web3 from 'web3';
 
-// import { AccountLevelsContract } from '../../src/contract_wrappers/generated/account_levels';
-// import { ArbitrageContract } from '../../src/contract_wrappers/generated/arbitrage';
-// import { DummyTokenContract } from '../../src/contract_wrappers/generated/dummy_token';
-// import { EtherDeltaContract } from '../../src/contract_wrappers/generated/ether_delta';
-// import { ExchangeContract } from '../../src/contract_wrappers/generated/exchange';
-// import { TokenTransferProxyContract } from '../../src/contract_wrappers/generated/token_transfer_proxy';
+// import { AccountLevelsContract } from '../../src/generated_contract_wrappers/account_levels';
+// import { ArbitrageContract } from '../../src/generated_contract_wrappers/arbitrage';
+// import { DummyTokenContract } from '../../src/generated_contract_wrappers/dummy_token';
+// import { EtherDeltaContract } from '../../src/generated_contract_wrappers/ether_delta';
+// import { ExchangeContract } from '../../src/generated_contract_wrappers/exchange';
+// import { TokenTransferProxyContract } from '../../src/generated_contract_wrappers/token_transfer_proxy';
 // import { artifacts } from '../../util/artifacts';
 // import { Balances } from '../../util/balances';
 // import { constants } from '../../util/constants';
diff --git a/packages/contracts/test/unlimited_allowance_token.ts b/packages/contracts/test/unlimited_allowance_token.ts
index b2acdebaa..0c3f5094b 100644
--- a/packages/contracts/test/unlimited_allowance_token.ts
+++ b/packages/contracts/test/unlimited_allowance_token.ts
@@ -1,12 +1,11 @@
-import { BlockchainLifecycle, devConstants, web3Factory } from '@0xproject/dev-utils';
+import { BlockchainLifecycle } from '@0xproject/dev-utils';
 import { BigNumber } from '@0xproject/utils';
-import { Web3Wrapper } from '@0xproject/web3-wrapper';
 import * as chai from 'chai';
 import 'make-promises-safe';
-import * as Web3 from 'web3';
 
-import { DummyERC20TokenContract } from '../src/contract_wrappers/generated/dummy_e_r_c20_token';
+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';
@@ -55,8 +54,9 @@ describe('UnlimitedAllowanceToken', () => {
         it('should throw if owner has insufficient balance', async () => {
             const ownerBalance = await token.balanceOf.callAsync(owner);
             const amountToTransfer = ownerBalance.plus(1);
-            return expect(token.transfer.callAsync(spender, amountToTransfer, { from: owner })).to.be.rejectedWith(
-                constants.REVERT,
+            return expectRevertOrOtherErrorAsync(
+                token.transfer.callAsync(spender, amountToTransfer, { from: owner }),
+                constants.ERC20_INSUFFICIENT_BALANCE,
             );
         });
 
@@ -93,11 +93,12 @@ describe('UnlimitedAllowanceToken', () => {
                 await token.approve.sendTransactionAsync(spender, amountToTransfer, { from: owner }),
                 constants.AWAIT_TRANSACTION_MINED_MS,
             );
-            return expect(
+            return expectRevertOrOtherErrorAsync(
                 token.transferFrom.callAsync(owner, spender, amountToTransfer, {
                     from: spender,
                 }),
-            ).to.be.rejectedWith(constants.REVERT);
+                constants.ERC20_INSUFFICIENT_BALANCE,
+            );
         });
 
         it('should throw if spender has insufficient allowance', async () => {
@@ -108,11 +109,12 @@ describe('UnlimitedAllowanceToken', () => {
             const isSpenderAllowanceInsufficient = spenderAllowance.cmp(amountToTransfer) < 0;
             expect(isSpenderAllowanceInsufficient).to.be.true();
 
-            return expect(
+            return expectRevertOrOtherErrorAsync(
                 token.transferFrom.callAsync(owner, spender, amountToTransfer, {
                     from: spender,
                 }),
-            ).to.be.rejectedWith(constants.REVERT);
+                constants.ERC20_INSUFFICIENT_ALLOWANCE,
+            );
         });
 
         it('should return true on a 0 value transfer', async () => {
diff --git a/packages/contracts/test/zrx_token.ts b/packages/contracts/test/zrx_token.ts
index fe37e802b..0629c7a88 100644
--- a/packages/contracts/test/zrx_token.ts
+++ b/packages/contracts/test/zrx_token.ts
@@ -1,11 +1,10 @@
-import { BlockchainLifecycle, devConstants, web3Factory } from '@0xproject/dev-utils';
+import { BlockchainLifecycle } from '@0xproject/dev-utils';
 import { BigNumber } from '@0xproject/utils';
 import { Web3Wrapper } from '@0xproject/web3-wrapper';
 import * as chai from 'chai';
 import 'make-promises-safe';
-import * as Web3 from 'web3';
 
-import { ZRXTokenContract } from '../src/contract_wrappers/generated/zrx_token';
+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';
@@ -79,7 +78,10 @@ describe('ZRXToken', () => {
             const receiver = spender;
             const initOwnerBalance = await zrxToken.balanceOf.callAsync(owner);
             const amountToTransfer = new BigNumber(1);
-            await zrxToken.transfer.sendTransactionAsync(receiver, amountToTransfer, { from: owner });
+            await web3Wrapper.awaitTransactionSuccessAsync(
+                await zrxToken.transfer.sendTransactionAsync(receiver, amountToTransfer, { from: owner }),
+                constants.AWAIT_TRANSACTION_MINED_MS,
+            );
             const finalOwnerBalance = await zrxToken.balanceOf.callAsync(owner);
             const finalReceiverBalance = await zrxToken.balanceOf.callAsync(receiver);
 
@@ -101,10 +103,13 @@ describe('ZRXToken', () => {
         it('should return false if owner has insufficient balance', async () => {
             const ownerBalance = await zrxToken.balanceOf.callAsync(owner);
             const amountToTransfer = ownerBalance.plus(1);
-            await zrxToken.approve.sendTransactionAsync(spender, amountToTransfer, {
-                from: owner,
-                gas: constants.MAX_TOKEN_APPROVE_GAS,
-            });
+            await web3Wrapper.awaitTransactionSuccessAsync(
+                await zrxToken.approve.sendTransactionAsync(spender, amountToTransfer, {
+                    from: owner,
+                    gas: constants.MAX_TOKEN_APPROVE_GAS,
+                }),
+                constants.AWAIT_TRANSACTION_MINED_MS,
+            );
             const didReturnTrue = await zrxToken.transferFrom.callAsync(owner, spender, amountToTransfer, {
                 from: spender,
             });
@@ -137,14 +142,20 @@ describe('ZRXToken', () => {
             const initOwnerBalance = await zrxToken.balanceOf.callAsync(owner);
             const amountToTransfer = initOwnerBalance;
             const initSpenderAllowance = MAX_UINT;
-            await zrxToken.approve.sendTransactionAsync(spender, initSpenderAllowance, {
-                from: owner,
-                gas: constants.MAX_TOKEN_APPROVE_GAS,
-            });
-            await zrxToken.transferFrom.sendTransactionAsync(owner, spender, amountToTransfer, {
-                from: spender,
-                gas: constants.MAX_TOKEN_TRANSFERFROM_GAS,
-            });
+            await web3Wrapper.awaitTransactionSuccessAsync(
+                await zrxToken.approve.sendTransactionAsync(spender, initSpenderAllowance, {
+                    from: owner,
+                    gas: constants.MAX_TOKEN_APPROVE_GAS,
+                }),
+                constants.AWAIT_TRANSACTION_MINED_MS,
+            );
+            await web3Wrapper.awaitTransactionSuccessAsync(
+                await zrxToken.transferFrom.sendTransactionAsync(owner, spender, amountToTransfer, {
+                    from: spender,
+                    gas: constants.MAX_TOKEN_TRANSFERFROM_GAS,
+                }),
+                constants.AWAIT_TRANSACTION_MINED_MS,
+            );
 
             const newSpenderAllowance = await zrxToken.allowance.callAsync(owner, spender);
             expect(initSpenderAllowance).to.be.bignumber.equal(newSpenderAllowance);
@@ -155,11 +166,17 @@ describe('ZRXToken', () => {
             const initSpenderBalance = await zrxToken.balanceOf.callAsync(spender);
             const amountToTransfer = initOwnerBalance;
             const initSpenderAllowance = initOwnerBalance;
-            await zrxToken.approve.sendTransactionAsync(spender, initSpenderAllowance);
-            await zrxToken.transferFrom.sendTransactionAsync(owner, spender, amountToTransfer, {
-                from: spender,
-                gas: constants.MAX_TOKEN_TRANSFERFROM_GAS,
-            });
+            await web3Wrapper.awaitTransactionSuccessAsync(
+                await zrxToken.approve.sendTransactionAsync(spender, initSpenderAllowance),
+                constants.AWAIT_TRANSACTION_MINED_MS,
+            );
+            await web3Wrapper.awaitTransactionSuccessAsync(
+                await zrxToken.transferFrom.sendTransactionAsync(owner, spender, amountToTransfer, {
+                    from: spender,
+                    gas: constants.MAX_TOKEN_TRANSFERFROM_GAS,
+                }),
+                constants.AWAIT_TRANSACTION_MINED_MS,
+            );
 
             const newOwnerBalance = await zrxToken.balanceOf.callAsync(owner);
             const newSpenderBalance = await zrxToken.balanceOf.callAsync(spender);
@@ -171,11 +188,17 @@ describe('ZRXToken', () => {
         it('should modify allowance if spender has sufficient allowance less than 2^256 - 1', async () => {
             const initOwnerBalance = await zrxToken.balanceOf.callAsync(owner);
             const amountToTransfer = initOwnerBalance;
-            await zrxToken.approve.sendTransactionAsync(spender, amountToTransfer);
-            await zrxToken.transferFrom.sendTransactionAsync(owner, spender, amountToTransfer, {
-                from: spender,
-                gas: constants.MAX_TOKEN_TRANSFERFROM_GAS,
-            });
+            await web3Wrapper.awaitTransactionSuccessAsync(
+                await zrxToken.approve.sendTransactionAsync(spender, amountToTransfer),
+                constants.AWAIT_TRANSACTION_MINED_MS,
+            );
+            await web3Wrapper.awaitTransactionSuccessAsync(
+                await zrxToken.transferFrom.sendTransactionAsync(owner, spender, amountToTransfer, {
+                    from: spender,
+                    gas: constants.MAX_TOKEN_TRANSFERFROM_GAS,
+                }),
+                constants.AWAIT_TRANSACTION_MINED_MS,
+            );
 
             const newSpenderAllowance = await zrxToken.allowance.callAsync(owner, spender);
             expect(newSpenderAllowance).to.be.bignumber.equal(0);