Merge branch 'v2-prototype' into invalid-argument-error

13 files changed, 768 insertions, 721 deletions

diff --git a/packages/contracts/test/asset_proxy/authorizable.ts b/packages/contracts/test/asset_proxy/authorizable.ts
index ed582b63e..8c9d0495d 100644
--- a/packages/contracts/test/asset_proxy/authorizable.ts
+++ b/packages/contracts/test/asset_proxy/authorizable.ts
@@ -1,9 +1,11 @@
 import { BlockchainLifecycle } from '@0xproject/dev-utils';
+import { RevertReason } from '@0xproject/types';
+import { BigNumber } from '@0xproject/utils';
 import * as chai from 'chai';
 
 import { MixinAuthorizableContract } from '../../src/generated_contract_wrappers/mixin_authorizable';
 import { artifacts } from '../../src/utils/artifacts';
-import { expectRevertOrAlwaysFailingTransactionAsync } from '../../src/utils/assertions';
+import { expectRevertReasonOrAlwaysFailingTransactionAsync } from '../../src/utils/assertions';
 import { chaiSetup } from '../../src/utils/chai_setup';
 import { constants } from '../../src/utils/constants';
 import { provider, txDefaults, web3Wrapper } from '../../src/utils/web3_wrapper';
@@ -42,8 +44,9 @@ describe('Authorizable', () => {
     });
     describe('addAuthorizedAddress', () => {
         it('should throw if not called by owner', async () => {
-            return expectRevertOrAlwaysFailingTransactionAsync(
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
                 authorizable.addAuthorizedAddress.sendTransactionAsync(notOwner, { from: notOwner }),
+                RevertReason.OnlyContractOwner,
             );
         });
         it('should allow owner to add an authorized address', async () => {
@@ -59,8 +62,9 @@ describe('Authorizable', () => {
                 await authorizable.addAuthorizedAddress.sendTransactionAsync(address, { from: owner }),
                 constants.AWAIT_TRANSACTION_MINED_MS,
             );
-            return expectRevertOrAlwaysFailingTransactionAsync(
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
                 authorizable.addAuthorizedAddress.sendTransactionAsync(address, { from: owner }),
+                RevertReason.TargetAlreadyAuthorized,
             );
         });
     });
@@ -71,10 +75,11 @@ describe('Authorizable', () => {
                 await authorizable.addAuthorizedAddress.sendTransactionAsync(address, { from: owner }),
                 constants.AWAIT_TRANSACTION_MINED_MS,
             );
-            return expectRevertOrAlwaysFailingTransactionAsync(
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
                 authorizable.removeAuthorizedAddress.sendTransactionAsync(address, {
                     from: notOwner,
                 }),
+                RevertReason.OnlyContractOwner,
             );
         });
 
@@ -94,14 +99,87 @@ describe('Authorizable', () => {
         });
 
         it('should throw if owner attempts to remove an address that is not authorized', async () => {
-            return expectRevertOrAlwaysFailingTransactionAsync(
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
                 authorizable.removeAuthorizedAddress.sendTransactionAsync(address, {
                     from: owner,
                 }),
+                RevertReason.TargetNotAuthorized,
             );
         });
     });
 
+    describe('removeAuthorizedAddressAtIndex', () => {
+        it('should throw if not called by owner', async () => {
+            await web3Wrapper.awaitTransactionSuccessAsync(
+                await authorizable.addAuthorizedAddress.sendTransactionAsync(address, { from: owner }),
+                constants.AWAIT_TRANSACTION_MINED_MS,
+            );
+            const index = new BigNumber(0);
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
+                authorizable.removeAuthorizedAddressAtIndex.sendTransactionAsync(address, index, {
+                    from: notOwner,
+                }),
+                RevertReason.OnlyContractOwner,
+            );
+        });
+        it('should throw if index is >= authorities.length', async () => {
+            await web3Wrapper.awaitTransactionSuccessAsync(
+                await authorizable.addAuthorizedAddress.sendTransactionAsync(address, { from: owner }),
+                constants.AWAIT_TRANSACTION_MINED_MS,
+            );
+            const index = new BigNumber(1);
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
+                authorizable.removeAuthorizedAddressAtIndex.sendTransactionAsync(address, index, {
+                    from: owner,
+                }),
+                RevertReason.IndexOutOfBounds,
+            );
+        });
+        it('should throw if owner attempts to remove an address that is not authorized', async () => {
+            const index = new BigNumber(0);
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
+                authorizable.removeAuthorizedAddressAtIndex.sendTransactionAsync(address, index, {
+                    from: owner,
+                }),
+                RevertReason.TargetNotAuthorized,
+            );
+        });
+        it('should throw if address at index does not match target', async () => {
+            const address1 = address;
+            const address2 = notOwner;
+            await web3Wrapper.awaitTransactionSuccessAsync(
+                await authorizable.addAuthorizedAddress.sendTransactionAsync(address1, { from: owner }),
+                constants.AWAIT_TRANSACTION_MINED_MS,
+            );
+            await web3Wrapper.awaitTransactionSuccessAsync(
+                await authorizable.addAuthorizedAddress.sendTransactionAsync(address2, { from: owner }),
+                constants.AWAIT_TRANSACTION_MINED_MS,
+            );
+            const address1Index = new BigNumber(0);
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
+                authorizable.removeAuthorizedAddressAtIndex.sendTransactionAsync(address2, address1Index, {
+                    from: owner,
+                }),
+                RevertReason.AuthorizedAddressMismatch,
+            );
+        });
+        it('should allow owner to remove an authorized address', async () => {
+            await web3Wrapper.awaitTransactionSuccessAsync(
+                await authorizable.addAuthorizedAddress.sendTransactionAsync(address, { from: owner }),
+                constants.AWAIT_TRANSACTION_MINED_MS,
+            );
+            const index = new BigNumber(0);
+            await web3Wrapper.awaitTransactionSuccessAsync(
+                await authorizable.removeAuthorizedAddressAtIndex.sendTransactionAsync(address, index, {
+                    from: owner,
+                }),
+                constants.AWAIT_TRANSACTION_MINED_MS,
+            );
+            const isAuthorized = await authorizable.authorized.callAsync(address);
+            expect(isAuthorized).to.be.false();
+        });
+    });
+
     describe('getAuthorizedAddresses', () => {
         it('should return all authorized addresses', async () => {
             const initial = await authorizable.getAuthorizedAddresses.callAsync();
diff --git a/packages/contracts/test/asset_proxy/decoder.ts b/packages/contracts/test/asset_proxy/decoder.ts
deleted file mode 100644
index 875d55daa..000000000
--- a/packages/contracts/test/asset_proxy/decoder.ts
+++ /dev/null
@@ -1,86 +0,0 @@
-import { BlockchainLifecycle } from '@0xproject/dev-utils';
-import { assetProxyUtils, generatePseudoRandomSalt } from '@0xproject/order-utils';
-import { BigNumber } from '@0xproject/utils';
-import * as chai from 'chai';
-import ethUtil = require('ethereumjs-util');
-
-import { TestAssetDataDecodersContract } from '../../src/generated_contract_wrappers/test_asset_data_decoders';
-import { artifacts } from '../../src/utils/artifacts';
-import { chaiSetup } from '../../src/utils/chai_setup';
-import { provider, txDefaults, web3Wrapper } from '../../src/utils/web3_wrapper';
-
-chaiSetup.configure();
-const expect = chai.expect;
-const blockchainLifecycle = new BlockchainLifecycle(web3Wrapper);
-
-describe('TestAssetDataDecoders', () => {
-    let testAssetProxyDecoder: TestAssetDataDecodersContract;
-    let testAddress: string;
-
-    before(async () => {
-        await blockchainLifecycle.startAsync();
-    });
-    after(async () => {
-        await blockchainLifecycle.revertAsync();
-    });
-    before(async () => {
-        // Setup accounts & addresses
-        const accounts = await web3Wrapper.getAvailableAddressesAsync();
-        testAddress = accounts[0];
-        // 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 2c27f7382..595839519 100644
--- a/packages/contracts/test/asset_proxy/proxies.ts
+++ b/packages/contracts/test/asset_proxy/proxies.ts
@@ -1,10 +1,10 @@
 import { BlockchainLifecycle } from '@0xproject/dev-utils';
 import { assetProxyUtils, generatePseudoRandomSalt } from '@0xproject/order-utils';
+import { RevertReason } from '@0xproject/types';
 import { BigNumber } from '@0xproject/utils';
 import * as chai from 'chai';
 import { LogWithDecodedArgs } from 'ethereum-types';
 import ethUtil = require('ethereumjs-util');
-import * as _ from 'lodash';
 
 import { DummyERC20TokenContract } from '../../src/generated_contract_wrappers/dummy_e_r_c20_token';
 import {
@@ -15,7 +15,7 @@ import { DummyERC721TokenContract } from '../../src/generated_contract_wrappers/
 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 { expectRevertReasonOrAlwaysFailingTransactionAsync } from '../../src/utils/assertions';
 import { chaiSetup } from '../../src/utils/chai_setup';
 import { constants } from '../../src/utils/constants';
 import { ERC20Wrapper } from '../../src/utils/erc20_wrapper';
@@ -96,13 +96,12 @@ describe('Asset Transfer Proxies', () => {
             it('should successfully transfer tokens', async () => {
                 // Construct ERC20 asset data
                 const encodedAssetData = assetProxyUtils.encodeERC20AssetData(zrxToken.address);
-                const encodedAssetDataWithoutProxyId = encodedAssetData.slice(0, -2);
                 // Perform a transfer from makerAddress to takerAddress
                 const erc20Balances = await erc20Wrapper.getBalancesAsync();
                 const amount = new BigNumber(10);
                 await web3Wrapper.awaitTransactionSuccessAsync(
                     await erc20Proxy.transferFrom.sendTransactionAsync(
-                        encodedAssetDataWithoutProxyId,
+                        encodedAssetData,
                         makerAddress,
                         takerAddress,
                         amount,
@@ -123,13 +122,12 @@ describe('Asset Transfer Proxies', () => {
             it('should do nothing if transferring 0 amount of a token', async () => {
                 // Construct ERC20 asset data
                 const encodedAssetData = assetProxyUtils.encodeERC20AssetData(zrxToken.address);
-                const encodedAssetDataWithoutProxyId = encodedAssetData.slice(0, -2);
                 // Perform a transfer from makerAddress to takerAddress
                 const erc20Balances = await erc20Wrapper.getBalancesAsync();
                 const amount = new BigNumber(0);
                 await web3Wrapper.awaitTransactionSuccessAsync(
                     await erc20Proxy.transferFrom.sendTransactionAsync(
-                        encodedAssetDataWithoutProxyId,
+                        encodedAssetData,
                         makerAddress,
                         takerAddress,
                         amount,
@@ -160,93 +158,37 @@ describe('Asset Transfer Proxies', () => {
                     constants.AWAIT_TRANSACTION_MINED_MS,
                 );
                 // Perform a transfer; expect this to fail.
-                return expectRevertOrAlwaysFailingTransactionAsync(
+                return expectRevertReasonOrAlwaysFailingTransactionAsync(
                     erc20Proxy.transferFrom.sendTransactionAsync(
                         encodedAssetData,
                         makerAddress,
                         takerAddress,
                         transferAmount,
-                        { from: notAuthorized },
+                        { from: exchangeAddress },
                     ),
+                    RevertReason.TransferFailed,
                 );
             });
 
             it('should throw if requesting address is not authorized', async () => {
                 // Construct ERC20 asset data
                 const encodedAssetData = assetProxyUtils.encodeERC20AssetData(zrxToken.address);
-                const encodedAssetDataWithoutProxyId = encodedAssetData.slice(0, -2);
-                // Perform a transfer from makerAddress to takerAddress
-                const amount = new BigNumber(10);
-                return expectRevertOrAlwaysFailingTransactionAsync(
-                    erc20Proxy.transferFrom.sendTransactionAsync(
-                        encodedAssetDataWithoutProxyId,
-                        makerAddress,
-                        takerAddress,
-                        amount,
-                        {
-                            from: notAuthorized,
-                        },
-                    ),
-                );
-            });
-        });
-
-        describe('batchTransferFrom', () => {
-            it('should succesfully make multiple token transfers', async () => {
-                const erc20Balances = await erc20Wrapper.getBalancesAsync();
-
-                const encodedAssetData = assetProxyUtils.encodeERC20AssetData(zrxToken.address);
-                const encodedAssetDataWithoutProxyId = encodedAssetData.slice(0, -2);
-                const amount = new BigNumber(10);
-                const numTransfers = 2;
-                const assetData = _.times(numTransfers, () => encodedAssetDataWithoutProxyId);
-                const fromAddresses = _.times(numTransfers, () => makerAddress);
-                const toAddresses = _.times(numTransfers, () => takerAddress);
-                const amounts = _.times(numTransfers, () => amount);
-
-                const txHash = await erc20Proxy.batchTransferFrom.sendTransactionAsync(
-                    assetData,
-                    fromAddresses,
-                    toAddresses,
-                    amounts,
-                    { from: exchangeAddress },
-                );
-                const res = await web3Wrapper.awaitTransactionSuccessAsync(
-                    txHash,
-                    constants.AWAIT_TRANSACTION_MINED_MS,
-                );
-                const newBalances = await erc20Wrapper.getBalancesAsync();
-
-                expect(res.logs.length).to.equal(numTransfers);
-                expect(newBalances[makerAddress][zrxToken.address]).to.be.bignumber.equal(
-                    erc20Balances[makerAddress][zrxToken.address].minus(amount.times(numTransfers)),
-                );
-                expect(newBalances[takerAddress][zrxToken.address]).to.be.bignumber.equal(
-                    erc20Balances[takerAddress][zrxToken.address].add(amount.times(numTransfers)),
-                );
-            });
 
-            it('should throw if not called by an authorized address', async () => {
-                const encodedAssetData = assetProxyUtils.encodeERC20AssetData(zrxToken.address);
-                const encodedAssetDataWithoutProxyId = encodedAssetData.slice(0, -2);
+                // Perform a transfer from makerAddress to takerAddress
                 const amount = new BigNumber(10);
-                const numTransfers = 2;
-                const assetData = _.times(numTransfers, () => encodedAssetDataWithoutProxyId);
-                const fromAddresses = _.times(numTransfers, () => makerAddress);
-                const toAddresses = _.times(numTransfers, () => takerAddress);
-                const amounts = _.times(numTransfers, () => amount);
-
-                return expectRevertOrAlwaysFailingTransactionAsync(
-                    erc20Proxy.batchTransferFrom.sendTransactionAsync(assetData, fromAddresses, toAddresses, amounts, {
+                return expectRevertReasonOrAlwaysFailingTransactionAsync(
+                    erc20Proxy.transferFrom.sendTransactionAsync(encodedAssetData, makerAddress, takerAddress, amount, {
                         from: notAuthorized,
                     }),
+                    RevertReason.SenderNotAuthorized,
                 );
             });
         });
 
-        it('should have an id of 1', async () => {
+        it('should have an id of 0xf47261b0', async () => {
             const proxyId = await erc20Proxy.getProxyId.callAsync();
-            expect(proxyId).to.equal(1);
+            const expectedProxyId = '0xf47261b0';
+            expect(proxyId).to.equal(expectedProxyId);
         });
     });
 
@@ -255,7 +197,6 @@ describe('Asset Transfer Proxies', () => {
             it('should successfully transfer tokens', async () => {
                 // Construct ERC721 asset data
                 const encodedAssetData = assetProxyUtils.encodeERC721AssetData(erc721Token.address, erc721MakerTokenId);
-                const encodedAssetDataWithoutProxyId = encodedAssetData.slice(0, -2);
                 // Verify pre-condition
                 const ownerMakerAsset = await erc721Token.ownerOf.callAsync(erc721MakerTokenId);
                 expect(ownerMakerAsset).to.be.bignumber.equal(makerAddress);
@@ -263,7 +204,7 @@ describe('Asset Transfer Proxies', () => {
                 const amount = new BigNumber(1);
                 await web3Wrapper.awaitTransactionSuccessAsync(
                     await erc721Proxy.transferFrom.sendTransactionAsync(
-                        encodedAssetDataWithoutProxyId,
+                        encodedAssetData,
                         makerAddress,
                         takerAddress,
                         amount,
@@ -279,14 +220,13 @@ describe('Asset Transfer Proxies', () => {
             it('should call onERC721Received when transferring to a smart contract without receiver data', async () => {
                 // Construct ERC721 asset data
                 const encodedAssetData = assetProxyUtils.encodeERC721AssetData(erc721Token.address, erc721MakerTokenId);
-                const encodedAssetDataWithoutProxyId = encodedAssetData.slice(0, -2);
                 // Verify pre-condition
                 const ownerMakerAsset = await erc721Token.ownerOf.callAsync(erc721MakerTokenId);
                 expect(ownerMakerAsset).to.be.bignumber.equal(makerAddress);
                 // Perform a transfer from makerAddress to takerAddress
                 const amount = new BigNumber(1);
                 const txHash = await erc721Proxy.transferFrom.sendTransactionAsync(
-                    encodedAssetDataWithoutProxyId,
+                    encodedAssetData,
                     makerAddress,
                     erc721Receiver.address,
                     amount,
@@ -315,14 +255,13 @@ describe('Asset Transfer Proxies', () => {
                     erc721MakerTokenId,
                     receiverData,
                 );
-                const encodedAssetDataWithoutProxyId = encodedAssetData.slice(0, -2);
                 // Verify pre-condition
                 const ownerMakerAsset = await erc721Token.ownerOf.callAsync(erc721MakerTokenId);
                 expect(ownerMakerAsset).to.be.bignumber.equal(makerAddress);
                 // Perform a transfer from makerAddress to takerAddress
                 const amount = new BigNumber(1);
                 const txHash = await erc721Proxy.transferFrom.sendTransactionAsync(
-                    encodedAssetDataWithoutProxyId,
+                    encodedAssetData,
                     makerAddress,
                     erc721Receiver.address,
                     amount,
@@ -351,67 +290,66 @@ describe('Asset Transfer Proxies', () => {
                     erc721MakerTokenId,
                     receiverData,
                 );
-                const encodedAssetDataWithoutProxyId = encodedAssetData.slice(0, -2);
                 // Verify pre-condition
                 const ownerMakerAsset = await erc721Token.ownerOf.callAsync(erc721MakerTokenId);
                 expect(ownerMakerAsset).to.be.bignumber.equal(makerAddress);
                 // Perform a transfer from makerAddress to takerAddress
                 const amount = new BigNumber(1);
-                return expectRevertOrAlwaysFailingTransactionAsync(
+                return expectRevertReasonOrAlwaysFailingTransactionAsync(
                     erc721Proxy.transferFrom.sendTransactionAsync(
-                        encodedAssetDataWithoutProxyId,
+                        encodedAssetData,
                         makerAddress,
                         erc20Proxy.address, // the ERC20 proxy does not have an ERC721 receiver
                         amount,
                         { from: exchangeAddress },
                     ),
+                    RevertReason.TransferFailed,
                 );
             });
 
             it('should throw if transferring 0 amount of a token', async () => {
                 // Construct ERC721 asset data
                 const encodedAssetData = assetProxyUtils.encodeERC721AssetData(erc721Token.address, erc721MakerTokenId);
-                const encodedAssetDataWithoutProxyId = encodedAssetData.slice(0, -2);
                 // Verify pre-condition
                 const ownerMakerAsset = await erc721Token.ownerOf.callAsync(erc721MakerTokenId);
                 expect(ownerMakerAsset).to.be.bignumber.equal(makerAddress);
                 // Perform a transfer from makerAddress to takerAddress
                 const amount = new BigNumber(0);
-                return expectRevertOrAlwaysFailingTransactionAsync(
+                return expectRevertReasonOrAlwaysFailingTransactionAsync(
                     erc721Proxy.transferFrom.sendTransactionAsync(
-                        encodedAssetDataWithoutProxyId,
+                        encodedAssetData,
                         makerAddress,
                         takerAddress,
                         amount,
                         { from: exchangeAddress },
                     ),
+                    RevertReason.InvalidAmount,
                 );
             });
 
             it('should throw if transferring > 1 amount of a token', async () => {
                 // Construct ERC721 asset data
                 const encodedAssetData = assetProxyUtils.encodeERC721AssetData(erc721Token.address, erc721MakerTokenId);
-                const encodedAssetDataWithoutProxyId = encodedAssetData.slice(0, -2);
                 // Verify pre-condition
                 const ownerMakerAsset = await erc721Token.ownerOf.callAsync(erc721MakerTokenId);
                 expect(ownerMakerAsset).to.be.bignumber.equal(makerAddress);
                 // Perform a transfer from makerAddress to takerAddress
                 const amount = new BigNumber(500);
-                return expectRevertOrAlwaysFailingTransactionAsync(
+                return expectRevertReasonOrAlwaysFailingTransactionAsync(
                     erc721Proxy.transferFrom.sendTransactionAsync(
-                        encodedAssetDataWithoutProxyId,
+                        encodedAssetData,
                         makerAddress,
                         takerAddress,
                         amount,
                         { from: exchangeAddress },
                     ),
+                    RevertReason.InvalidAmount,
                 );
             });
 
             it('should throw if allowances are too low', async () => {
                 // Construct ERC721 asset data
                 const encodedAssetData = assetProxyUtils.encodeERC721AssetData(erc721Token.address, erc721MakerTokenId);
-                const encodedAssetDataWithoutProxyId = encodedAssetData.slice(0, -2);
                 // Remove transfer approval for makerAddress.
                 await web3Wrapper.awaitTransactionSuccessAsync(
                     await erc721Token.setApprovalForAll.sendTransactionAsync(erc721Proxy.address, false, {
@@ -421,94 +359,36 @@ describe('Asset Transfer Proxies', () => {
                 );
                 // Perform a transfer; expect this to fail.
                 const amount = new BigNumber(1);
-                return expectRevertOrAlwaysFailingTransactionAsync(
-                    erc20Proxy.transferFrom.sendTransactionAsync(
-                        encodedAssetDataWithoutProxyId,
-                        makerAddress,
-                        takerAddress,
-                        amount,
-                        {
-                            from: notAuthorized,
-                        },
-                    ),
+                return expectRevertReasonOrAlwaysFailingTransactionAsync(
+                    erc20Proxy.transferFrom.sendTransactionAsync(encodedAssetData, makerAddress, takerAddress, amount, {
+                        from: exchangeAddress,
+                    }),
+                    RevertReason.TransferFailed,
                 );
             });
 
             it('should throw if requesting address is not authorized', async () => {
                 // Construct ERC721 asset data
                 const encodedAssetData = assetProxyUtils.encodeERC721AssetData(erc721Token.address, erc721MakerTokenId);
-                const encodedAssetDataWithoutProxyId = encodedAssetData.slice(0, -2);
                 // Perform a transfer from makerAddress to takerAddress
                 const amount = new BigNumber(1);
-                return expectRevertOrAlwaysFailingTransactionAsync(
+                return expectRevertReasonOrAlwaysFailingTransactionAsync(
                     erc721Proxy.transferFrom.sendTransactionAsync(
-                        encodedAssetDataWithoutProxyId,
+                        encodedAssetData,
                         makerAddress,
                         takerAddress,
                         amount,
                         { from: notAuthorized },
                     ),
+                    RevertReason.SenderNotAuthorized,
                 );
             });
         });
 
-        describe('batchTransferFrom', () => {
-            it('should succesfully make multiple token transfers', async () => {
-                const erc721TokensById = await erc721Wrapper.getBalancesAsync();
-                const [makerTokenIdA, makerTokenIdB] = erc721TokensById[makerAddress][erc721Token.address];
-
-                const numTransfers = 2;
-                const assetData = [
-                    assetProxyUtils.encodeERC721AssetData(erc721Token.address, makerTokenIdA).slice(0, -2),
-                    assetProxyUtils.encodeERC721AssetData(erc721Token.address, makerTokenIdB).slice(0, -2),
-                ];
-                const fromAddresses = _.times(numTransfers, () => makerAddress);
-                const toAddresses = _.times(numTransfers, () => takerAddress);
-                const amounts = _.times(numTransfers, () => new BigNumber(1));
-
-                const txHash = await erc721Proxy.batchTransferFrom.sendTransactionAsync(
-                    assetData,
-                    fromAddresses,
-                    toAddresses,
-                    amounts,
-                    { from: exchangeAddress },
-                );
-                const res = await web3Wrapper.awaitTransactionSuccessAsync(
-                    txHash,
-                    constants.AWAIT_TRANSACTION_MINED_MS,
-                );
-                expect(res.logs.length).to.equal(numTransfers);
-
-                const newOwnerMakerAssetA = await erc721Token.ownerOf.callAsync(makerTokenIdA);
-                const newOwnerMakerAssetB = await erc721Token.ownerOf.callAsync(makerTokenIdB);
-                expect(newOwnerMakerAssetA).to.be.bignumber.equal(takerAddress);
-                expect(newOwnerMakerAssetB).to.be.bignumber.equal(takerAddress);
-            });
-
-            it('should throw if not called by an authorized address', async () => {
-                const erc721TokensById = await erc721Wrapper.getBalancesAsync();
-                const [makerTokenIdA, makerTokenIdB] = erc721TokensById[makerAddress][erc721Token.address];
-
-                const numTransfers = 2;
-                const assetData = [
-                    assetProxyUtils.encodeERC721AssetData(erc721Token.address, makerTokenIdA).slice(0, -2),
-                    assetProxyUtils.encodeERC721AssetData(erc721Token.address, makerTokenIdB).slice(0, -2),
-                ];
-                const fromAddresses = _.times(numTransfers, () => makerAddress);
-                const toAddresses = _.times(numTransfers, () => takerAddress);
-                const amounts = _.times(numTransfers, () => new BigNumber(1));
-
-                return expectRevertOrAlwaysFailingTransactionAsync(
-                    erc721Proxy.batchTransferFrom.sendTransactionAsync(assetData, fromAddresses, toAddresses, amounts, {
-                        from: notAuthorized,
-                    }),
-                );
-            });
-        });
-
-        it('should have an id of 2', async () => {
+        it('should have an id of 0x08e937fa', async () => {
             const proxyId = await erc721Proxy.getProxyId.callAsync();
-            expect(proxyId).to.equal(2);
+            const expectedProxyId = '0x08e937fa';
+            expect(proxyId).to.equal(expectedProxyId);
         });
     });
 });
diff --git a/packages/contracts/test/asset_proxy_owner.ts b/packages/contracts/test/asset_proxy_owner.ts
index aa4999e95..188cba5a3 100644
--- a/packages/contracts/test/asset_proxy_owner.ts
+++ b/packages/contracts/test/asset_proxy_owner.ts
@@ -11,6 +11,7 @@ import {
     SubmissionContractEventArgs,
 } from '../src/generated_contract_wrappers/asset_proxy_owner';
 import { MixinAuthorizableContract } from '../src/generated_contract_wrappers/mixin_authorizable';
+import { TestAssetProxyOwnerContract } from '../src/generated_contract_wrappers/test_asset_proxy_owner';
 import { artifacts } from '../src/utils/artifacts';
 import {
     expectRevertOrAlwaysFailingTransactionAsync,
@@ -34,7 +35,7 @@ describe('AssetProxyOwner', () => {
 
     let erc20Proxy: MixinAuthorizableContract;
     let erc721Proxy: MixinAuthorizableContract;
-    let multiSig: AssetProxyOwnerContract;
+    let testAssetProxyOwner: TestAssetProxyOwnerContract;
     let multiSigWrapper: MultiSigWrapper;
 
     before(async () => {
@@ -58,8 +59,8 @@ describe('AssetProxyOwner', () => {
             txDefaults,
         );
         const defaultAssetProxyContractAddresses: string[] = [];
-        multiSig = await AssetProxyOwnerContract.deployFrom0xArtifactAsync(
-            artifacts.AssetProxyOwner,
+        testAssetProxyOwner = await TestAssetProxyOwnerContract.deployFrom0xArtifactAsync(
+            artifacts.TestAssetProxyOwner,
             provider,
             txDefaults,
             owners,
@@ -67,13 +68,17 @@ describe('AssetProxyOwner', () => {
             REQUIRED_APPROVALS,
             SECONDS_TIME_LOCKED,
         );
-        multiSigWrapper = new MultiSigWrapper(multiSig, provider);
+        multiSigWrapper = new MultiSigWrapper(testAssetProxyOwner, provider);
         await web3Wrapper.awaitTransactionSuccessAsync(
-            await erc20Proxy.transferOwnership.sendTransactionAsync(multiSig.address, { from: initialOwner }),
+            await erc20Proxy.transferOwnership.sendTransactionAsync(testAssetProxyOwner.address, {
+                from: initialOwner,
+            }),
             constants.AWAIT_TRANSACTION_MINED_MS,
         );
         await web3Wrapper.awaitTransactionSuccessAsync(
-            await erc721Proxy.transferOwnership.sendTransactionAsync(multiSig.address, { from: initialOwner }),
+            await erc721Proxy.transferOwnership.sendTransactionAsync(testAssetProxyOwner.address, {
+                from: initialOwner,
+            }),
             constants.AWAIT_TRANSACTION_MINED_MS,
         );
     });
@@ -117,24 +122,28 @@ describe('AssetProxyOwner', () => {
         });
     });
 
-    describe('isFunctionRemoveAuthorizedAddress', () => {
-        it('should throw if data is not for removeAuthorizedAddress', async () => {
+    describe('isFunctionRemoveAuthorizedAddressAtIndex', () => {
+        it('should return false if data is not for removeAuthorizedAddressAtIndex', async () => {
             const notRemoveAuthorizedAddressData = erc20Proxy.addAuthorizedAddress.getABIEncodedTransactionData(
                 owners[0],
             );
-            return expectRevertOrContractCallFailedAsync(
-                multiSig.isFunctionRemoveAuthorizedAddress.callAsync(notRemoveAuthorizedAddressData),
+
+            const isFunctionRemoveAuthorizedAddressAtIndex = await testAssetProxyOwner.isFunctionRemoveAuthorizedAddressAtIndex.callAsync(
+                notRemoveAuthorizedAddressData,
             );
+            expect(isFunctionRemoveAuthorizedAddressAtIndex).to.be.false();
         });
 
-        it('should return true if data is for removeAuthorizedAddress', async () => {
-            const removeAuthorizedAddressData = erc20Proxy.removeAuthorizedAddress.getABIEncodedTransactionData(
+        it('should return true if data is for removeAuthorizedAddressAtIndex', async () => {
+            const index = new BigNumber(0);
+            const removeAuthorizedAddressAtIndexData = erc20Proxy.removeAuthorizedAddressAtIndex.getABIEncodedTransactionData(
                 owners[0],
+                index,
             );
-            const isFunctionRemoveAuthorizedAddress = await multiSig.isFunctionRemoveAuthorizedAddress.callAsync(
-                removeAuthorizedAddressData,
+            const isFunctionRemoveAuthorizedAddressAtIndex = await testAssetProxyOwner.isFunctionRemoveAuthorizedAddressAtIndex.callAsync(
+                removeAuthorizedAddressAtIndexData,
             );
-            expect(isFunctionRemoveAuthorizedAddress).to.be.true();
+            expect(isFunctionRemoveAuthorizedAddressAtIndex).to.be.true();
         });
     });
 
@@ -142,19 +151,21 @@ describe('AssetProxyOwner', () => {
         it('should throw if not called by multisig', async () => {
             const isRegistered = true;
             return expectRevertOrAlwaysFailingTransactionAsync(
-                multiSig.registerAssetProxy.sendTransactionAsync(erc20Proxy.address, isRegistered, { from: owners[0] }),
+                testAssetProxyOwner.registerAssetProxy.sendTransactionAsync(erc20Proxy.address, isRegistered, {
+                    from: owners[0],
+                }),
             );
         });
 
         it('should register an address if called by multisig after timelock', async () => {
             const addressToRegister = erc20Proxy.address;
             const isRegistered = true;
-            const registerAssetProxyData = multiSig.registerAssetProxy.getABIEncodedTransactionData(
+            const registerAssetProxyData = testAssetProxyOwner.registerAssetProxy.getABIEncodedTransactionData(
                 addressToRegister,
                 isRegistered,
             );
             const submitTxRes = await multiSigWrapper.submitTransactionAsync(
-                multiSig.address,
+                testAssetProxyOwner.address,
                 registerAssetProxyData,
                 owners[0],
             );
@@ -170,19 +181,21 @@ describe('AssetProxyOwner', () => {
             expect(registerLog.args.assetProxyContract).to.equal(addressToRegister);
             expect(registerLog.args.isRegistered).to.equal(isRegistered);
 
-            const isAssetProxyRegistered = await multiSig.isAssetProxyRegistered.callAsync(addressToRegister);
+            const isAssetProxyRegistered = await testAssetProxyOwner.isAssetProxyRegistered.callAsync(
+                addressToRegister,
+            );
             expect(isAssetProxyRegistered).to.equal(isRegistered);
         });
 
         it('should fail if registering a null address', async () => {
             const addressToRegister = constants.NULL_ADDRESS;
             const isRegistered = true;
-            const registerAssetProxyData = multiSig.registerAssetProxy.getABIEncodedTransactionData(
+            const registerAssetProxyData = testAssetProxyOwner.registerAssetProxy.getABIEncodedTransactionData(
                 addressToRegister,
                 isRegistered,
             );
             const submitTxRes = await multiSigWrapper.submitTransactionAsync(
-                multiSig.address,
+                testAssetProxyOwner.address,
                 registerAssetProxyData,
                 owners[0],
             );
@@ -196,22 +209,26 @@ describe('AssetProxyOwner', () => {
             const failureLog = executeTxRes.logs[0] as LogWithDecodedArgs<ExecutionFailureContractEventArgs>;
             expect(failureLog.args.transactionId).to.be.bignumber.equal(txId);
 
-            const isAssetProxyRegistered = await multiSig.isAssetProxyRegistered.callAsync(addressToRegister);
+            const isAssetProxyRegistered = await testAssetProxyOwner.isAssetProxyRegistered.callAsync(
+                addressToRegister,
+            );
             expect(isAssetProxyRegistered).to.equal(false);
         });
     });
 
-    describe('executeRemoveAuthorizedAddress', () => {
+    describe('Calling removeAuthorizedAddressAtIndex', () => {
+        const erc20Index = new BigNumber(0);
+        const erc721Index = new BigNumber(1);
         before('authorize both proxies and register erc20 proxy', async () => {
             // Only register ERC20 proxy
             const addressToRegister = erc20Proxy.address;
             const isRegistered = true;
-            const registerAssetProxyData = multiSig.registerAssetProxy.getABIEncodedTransactionData(
+            const registerAssetProxyData = testAssetProxyOwner.registerAssetProxy.getABIEncodedTransactionData(
                 addressToRegister,
                 isRegistered,
             );
             const registerAssetProxySubmitRes = await multiSigWrapper.submitTransactionAsync(
-                multiSig.address,
+                testAssetProxyOwner.address,
                 registerAssetProxyData,
                 owners[0],
             );
@@ -248,113 +265,180 @@ describe('AssetProxyOwner', () => {
             await multiSigWrapper.executeTransactionAsync(erc721AddAuthorizedAddressTxId, owners[0]);
         });
 
-        it('should throw without the required confirmations', async () => {
-            const removeAuthorizedAddressData = erc20Proxy.removeAuthorizedAddress.getABIEncodedTransactionData(
-                authorized,
-            );
-            const res = await multiSigWrapper.submitTransactionAsync(
-                erc20Proxy.address,
-                removeAuthorizedAddressData,
-                owners[0],
-            );
-            const log = res.logs[0] as LogWithDecodedArgs<SubmissionContractEventArgs>;
-            const txId = log.args.transactionId;
-
-            return expectRevertOrAlwaysFailingTransactionAsync(
-                multiSig.executeRemoveAuthorizedAddress.sendTransactionAsync(txId, { from: owners[1] }),
-            );
-        });
-
-        it('should throw if tx destination is not registered', async () => {
-            const removeAuthorizedAddressData = erc721Proxy.removeAuthorizedAddress.getABIEncodedTransactionData(
-                authorized,
-            );
-            const res = await multiSigWrapper.submitTransactionAsync(
-                erc721Proxy.address,
-                removeAuthorizedAddressData,
-                owners[0],
-            );
-            const log = res.logs[0] as LogWithDecodedArgs<SubmissionContractEventArgs>;
-            const txId = log.args.transactionId;
-
-            await multiSigWrapper.confirmTransactionAsync(txId, owners[1]);
-
-            return expectRevertOrAlwaysFailingTransactionAsync(
-                multiSig.executeRemoveAuthorizedAddress.sendTransactionAsync(txId, { from: owners[1] }),
-            );
-        });
-
-        it('should throw if tx data is not for removeAuthorizedAddress', async () => {
-            const newAuthorized = owners[1];
-            const addAuthorizedAddressData = erc20Proxy.addAuthorizedAddress.getABIEncodedTransactionData(
-                newAuthorized,
-            );
-            const res = await multiSigWrapper.submitTransactionAsync(
-                erc20Proxy.address,
-                addAuthorizedAddressData,
-                owners[0],
-            );
-            const log = res.logs[0] as LogWithDecodedArgs<SubmissionContractEventArgs>;
-            const txId = log.args.transactionId;
-
-            await multiSigWrapper.confirmTransactionAsync(txId, owners[1]);
-
-            return expectRevertOrAlwaysFailingTransactionAsync(
-                multiSig.executeRemoveAuthorizedAddress.sendTransactionAsync(txId, { from: owners[1] }),
-            );
-        });
-
-        it('should execute removeAuthorizedAddress for registered address if fully confirmed', async () => {
-            const removeAuthorizedAddressData = erc20Proxy.removeAuthorizedAddress.getABIEncodedTransactionData(
-                authorized,
-            );
-            const submitRes = await multiSigWrapper.submitTransactionAsync(
-                erc20Proxy.address,
-                removeAuthorizedAddressData,
-                owners[0],
-            );
-            const submitLog = submitRes.logs[0] as LogWithDecodedArgs<SubmissionContractEventArgs>;
-            const txId = submitLog.args.transactionId;
-
-            await multiSigWrapper.confirmTransactionAsync(txId, owners[1]);
-
-            const execRes = await multiSigWrapper.executeRemoveAuthorizedAddressAsync(txId, owners[0]);
-            const execLog = execRes.logs[0] as LogWithDecodedArgs<ExecutionContractEventArgs>;
-            expect(execLog.args.transactionId).to.be.bignumber.equal(txId);
-
-            const tx = await multiSig.transactions.callAsync(txId);
-            const isExecuted = tx[3];
-            expect(isExecuted).to.equal(true);
-
-            const isAuthorized = await erc20Proxy.authorized.callAsync(authorized);
-            expect(isAuthorized).to.equal(false);
+        describe('validRemoveAuthorizedAddressAtIndexTx', () => {
+            it('should revert if data is not for removeAuthorizedAddressAtIndex and proxy is registered', async () => {
+                const notRemoveAuthorizedAddressData = erc20Proxy.addAuthorizedAddress.getABIEncodedTransactionData(
+                    authorized,
+                );
+                const submitTxRes = await multiSigWrapper.submitTransactionAsync(
+                    erc20Proxy.address,
+                    notRemoveAuthorizedAddressData,
+                    owners[0],
+                );
+                const log = submitTxRes.logs[0] as LogWithDecodedArgs<SubmissionContractEventArgs>;
+                const txId = log.args.transactionId;
+                return expectRevertOrContractCallFailedAsync(
+                    testAssetProxyOwner.testValidRemoveAuthorizedAddressAtIndexTx.callAsync(txId),
+                );
+            });
+
+            it('should return true if data is for removeAuthorizedAddressAtIndex and proxy is registered', async () => {
+                const removeAuthorizedAddressAtIndexData = erc20Proxy.removeAuthorizedAddressAtIndex.getABIEncodedTransactionData(
+                    authorized,
+                    erc20Index,
+                );
+                const submitTxRes = await multiSigWrapper.submitTransactionAsync(
+                    erc20Proxy.address,
+                    removeAuthorizedAddressAtIndexData,
+                    owners[0],
+                );
+                const log = submitTxRes.logs[0] as LogWithDecodedArgs<SubmissionContractEventArgs>;
+                const txId = log.args.transactionId;
+                const isValidRemoveAuthorizedAddressAtIndexTx = await testAssetProxyOwner.testValidRemoveAuthorizedAddressAtIndexTx.callAsync(
+                    txId,
+                );
+                expect(isValidRemoveAuthorizedAddressAtIndexTx).to.be.true();
+            });
+
+            it('should revert if data is for removeAuthorizedAddressAtIndex and proxy is not registered', async () => {
+                const removeAuthorizedAddressAtIndexData = erc721Proxy.removeAuthorizedAddressAtIndex.getABIEncodedTransactionData(
+                    authorized,
+                    erc721Index,
+                );
+                const submitTxRes = await multiSigWrapper.submitTransactionAsync(
+                    erc721Proxy.address,
+                    removeAuthorizedAddressAtIndexData,
+                    owners[0],
+                );
+                const log = submitTxRes.logs[0] as LogWithDecodedArgs<SubmissionContractEventArgs>;
+                const txId = log.args.transactionId;
+                return expectRevertOrContractCallFailedAsync(
+                    testAssetProxyOwner.testValidRemoveAuthorizedAddressAtIndexTx.callAsync(txId),
+                );
+            });
         });
 
-        it('should throw if already executed', async () => {
-            const removeAuthorizedAddressData = erc20Proxy.removeAuthorizedAddress.getABIEncodedTransactionData(
-                authorized,
-            );
-            const submitRes = await multiSigWrapper.submitTransactionAsync(
-                erc20Proxy.address,
-                removeAuthorizedAddressData,
-                owners[0],
-            );
-            const submitLog = submitRes.logs[0] as LogWithDecodedArgs<SubmissionContractEventArgs>;
-            const txId = submitLog.args.transactionId;
-
-            await multiSigWrapper.confirmTransactionAsync(txId, owners[1]);
-
-            const execRes = await multiSigWrapper.executeRemoveAuthorizedAddressAsync(txId, owners[0]);
-            const execLog = execRes.logs[0] as LogWithDecodedArgs<ExecutionContractEventArgs>;
-            expect(execLog.args.transactionId).to.be.bignumber.equal(txId);
-
-            const tx = await multiSig.transactions.callAsync(txId);
-            const isExecuted = tx[3];
-            expect(isExecuted).to.equal(true);
-
-            return expectRevertOrAlwaysFailingTransactionAsync(
-                multiSig.executeRemoveAuthorizedAddress.sendTransactionAsync(txId, { from: owners[1] }),
-            );
+        describe('executeRemoveAuthorizedAddressAtIndex', () => {
+            it('should throw without the required confirmations', async () => {
+                const removeAuthorizedAddressAtIndexData = erc20Proxy.removeAuthorizedAddressAtIndex.getABIEncodedTransactionData(
+                    authorized,
+                    erc20Index,
+                );
+                const res = await multiSigWrapper.submitTransactionAsync(
+                    erc20Proxy.address,
+                    removeAuthorizedAddressAtIndexData,
+                    owners[0],
+                );
+                const log = res.logs[0] as LogWithDecodedArgs<SubmissionContractEventArgs>;
+                const txId = log.args.transactionId;
+
+                return expectRevertOrAlwaysFailingTransactionAsync(
+                    testAssetProxyOwner.executeRemoveAuthorizedAddressAtIndex.sendTransactionAsync(txId, {
+                        from: owners[1],
+                    }),
+                );
+            });
+
+            it('should throw if tx destination is not registered', async () => {
+                const removeAuthorizedAddressAtIndexData = erc721Proxy.removeAuthorizedAddressAtIndex.getABIEncodedTransactionData(
+                    authorized,
+                    erc721Index,
+                );
+                const res = await multiSigWrapper.submitTransactionAsync(
+                    erc721Proxy.address,
+                    removeAuthorizedAddressAtIndexData,
+                    owners[0],
+                );
+                const log = res.logs[0] as LogWithDecodedArgs<SubmissionContractEventArgs>;
+                const txId = log.args.transactionId;
+
+                await multiSigWrapper.confirmTransactionAsync(txId, owners[1]);
+
+                return expectRevertOrAlwaysFailingTransactionAsync(
+                    testAssetProxyOwner.executeRemoveAuthorizedAddressAtIndex.sendTransactionAsync(txId, {
+                        from: owners[1],
+                    }),
+                );
+            });
+
+            it('should throw if tx data is not for removeAuthorizedAddressAtIndex', async () => {
+                const newAuthorized = owners[1];
+                const addAuthorizedAddressData = erc20Proxy.addAuthorizedAddress.getABIEncodedTransactionData(
+                    newAuthorized,
+                );
+                const res = await multiSigWrapper.submitTransactionAsync(
+                    erc20Proxy.address,
+                    addAuthorizedAddressData,
+                    owners[0],
+                );
+                const log = res.logs[0] as LogWithDecodedArgs<SubmissionContractEventArgs>;
+                const txId = log.args.transactionId;
+
+                await multiSigWrapper.confirmTransactionAsync(txId, owners[1]);
+
+                return expectRevertOrAlwaysFailingTransactionAsync(
+                    testAssetProxyOwner.executeRemoveAuthorizedAddressAtIndex.sendTransactionAsync(txId, {
+                        from: owners[1],
+                    }),
+                );
+            });
+
+            it('should execute removeAuthorizedAddressAtIndex for registered address if fully confirmed', async () => {
+                const removeAuthorizedAddressAtIndexData = erc20Proxy.removeAuthorizedAddressAtIndex.getABIEncodedTransactionData(
+                    authorized,
+                    erc20Index,
+                );
+                const submitRes = await multiSigWrapper.submitTransactionAsync(
+                    erc20Proxy.address,
+                    removeAuthorizedAddressAtIndexData,
+                    owners[0],
+                );
+                const submitLog = submitRes.logs[0] as LogWithDecodedArgs<SubmissionContractEventArgs>;
+                const txId = submitLog.args.transactionId;
+
+                await multiSigWrapper.confirmTransactionAsync(txId, owners[1]);
+
+                const execRes = await multiSigWrapper.executeRemoveAuthorizedAddressAtIndexAsync(txId, owners[0]);
+                const execLog = execRes.logs[0] as LogWithDecodedArgs<ExecutionContractEventArgs>;
+                expect(execLog.args.transactionId).to.be.bignumber.equal(txId);
+
+                const tx = await testAssetProxyOwner.transactions.callAsync(txId);
+                const isExecuted = tx[3];
+                expect(isExecuted).to.equal(true);
+
+                const isAuthorized = await erc20Proxy.authorized.callAsync(authorized);
+                expect(isAuthorized).to.equal(false);
+            });
+
+            it('should throw if already executed', async () => {
+                const removeAuthorizedAddressAtIndexData = erc20Proxy.removeAuthorizedAddressAtIndex.getABIEncodedTransactionData(
+                    authorized,
+                    erc20Index,
+                );
+                const submitRes = await multiSigWrapper.submitTransactionAsync(
+                    erc20Proxy.address,
+                    removeAuthorizedAddressAtIndexData,
+                    owners[0],
+                );
+                const submitLog = submitRes.logs[0] as LogWithDecodedArgs<SubmissionContractEventArgs>;
+                const txId = submitLog.args.transactionId;
+
+                await multiSigWrapper.confirmTransactionAsync(txId, owners[1]);
+
+                const execRes = await multiSigWrapper.executeRemoveAuthorizedAddressAtIndexAsync(txId, owners[0]);
+                const execLog = execRes.logs[0] as LogWithDecodedArgs<ExecutionContractEventArgs>;
+                expect(execLog.args.transactionId).to.be.bignumber.equal(txId);
+
+                const tx = await testAssetProxyOwner.transactions.callAsync(txId);
+                const isExecuted = tx[3];
+                expect(isExecuted).to.equal(true);
+
+                return expectRevertOrAlwaysFailingTransactionAsync(
+                    testAssetProxyOwner.executeRemoveAuthorizedAddressAtIndex.sendTransactionAsync(txId, {
+                        from: owners[1],
+                    }),
+                );
+            });
         });
     });
 });
diff --git a/packages/contracts/test/exchange/core.ts b/packages/contracts/test/exchange/core.ts
index ff652d3aa..36f6fa8d3 100644
--- a/packages/contracts/test/exchange/core.ts
+++ b/packages/contracts/test/exchange/core.ts
@@ -1,6 +1,6 @@
 import { BlockchainLifecycle } from '@0xproject/dev-utils';
 import { assetProxyUtils, orderHashUtils } from '@0xproject/order-utils';
-import { AssetProxyId, SignedOrder } from '@0xproject/types';
+import { AssetProxyId, RevertReason, SignedOrder } from '@0xproject/types';
 import { BigNumber } from '@0xproject/utils';
 import { Web3Wrapper } from '@0xproject/web3-wrapper';
 import * as chai from 'chai';
@@ -17,7 +17,7 @@ import {
     FillContractEventArgs,
 } from '../../src/generated_contract_wrappers/exchange';
 import { artifacts } from '../../src/utils/artifacts';
-import { expectRevertOrAlwaysFailingTransactionAsync } from '../../src/utils/assertions';
+import { expectRevertReasonOrAlwaysFailingTransactionAsync } from '../../src/utils/assertions';
 import { chaiSetup } from '../../src/utils/chai_setup';
 import { constants } from '../../src/utils/constants';
 import { ERC20Wrapper } from '../../src/utils/erc20_wrapper';
@@ -86,7 +86,7 @@ describe('Exchange core', () => {
             artifacts.Exchange,
             provider,
             txDefaults,
-            zrxToken.address,
+            assetProxyUtils.encodeERC20AssetData(zrxToken.address),
         );
         exchangeWrapper = new ExchangeWrapper(exchange, provider);
         await exchangeWrapper.registerAssetProxyAsync(AssetProxyId.ERC20, erc20Proxy.address, owner);
@@ -415,8 +415,9 @@ describe('Exchange core', () => {
                 makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(100), 18),
                 takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(200), 18),
             });
-            return expectRevertOrAlwaysFailingTransactionAsync(
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
                 exchangeWrapper.fillOrderAsync(signedOrder, takerAddress),
+                RevertReason.InvalidTaker,
             );
         });
 
@@ -432,8 +433,9 @@ describe('Exchange core', () => {
             const invalidSigBuff = Buffer.concat([v, invalidR, invalidS, signatureType]);
             const invalidSigHex = `0x${invalidSigBuff.toString('hex')}`;
             signedOrder.signature = invalidSigHex;
-            return expectRevertOrAlwaysFailingTransactionAsync(
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
                 exchangeWrapper.fillOrderAsync(signedOrder, takerAddress),
+                RevertReason.InvalidOrderSignature,
             );
         });
 
@@ -442,8 +444,9 @@ describe('Exchange core', () => {
                 makerAssetAmount: new BigNumber(0),
             });
 
-            return expectRevertOrAlwaysFailingTransactionAsync(
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
                 exchangeWrapper.fillOrderAsync(signedOrder, takerAddress),
+                RevertReason.OrderUnfillable,
             );
         });
 
@@ -452,18 +455,20 @@ describe('Exchange core', () => {
                 takerAssetAmount: new BigNumber(0),
             });
 
-            return expectRevertOrAlwaysFailingTransactionAsync(
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
                 exchangeWrapper.fillOrderAsync(signedOrder, takerAddress),
+                RevertReason.OrderUnfillable,
             );
         });
 
         it('should throw if takerAssetFillAmount is 0', async () => {
             signedOrder = orderFactory.newSignedOrder();
 
-            return expectRevertOrAlwaysFailingTransactionAsync(
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
                 exchangeWrapper.fillOrderAsync(signedOrder, takerAddress, {
                     takerAssetFillAmount: new BigNumber(0),
                 }),
+                RevertReason.InvalidTakerAmount,
             );
         });
 
@@ -472,8 +477,9 @@ describe('Exchange core', () => {
                 makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(100000), 18),
             });
 
-            return expectRevertOrAlwaysFailingTransactionAsync(
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
                 exchangeWrapper.fillOrderAsync(signedOrder, takerAddress),
+                RevertReason.TransferFailed,
             );
         });
 
@@ -481,8 +487,9 @@ describe('Exchange core', () => {
             signedOrder = orderFactory.newSignedOrder({
                 takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(100000), 18),
             });
-            return expectRevertOrAlwaysFailingTransactionAsync(
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
                 exchangeWrapper.fillOrderAsync(signedOrder, takerAddress),
+                RevertReason.TransferFailed,
             );
         });
 
@@ -493,8 +500,9 @@ describe('Exchange core', () => {
                 }),
                 constants.AWAIT_TRANSACTION_MINED_MS,
             );
-            return expectRevertOrAlwaysFailingTransactionAsync(
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
                 exchangeWrapper.fillOrderAsync(signedOrder, takerAddress),
+                RevertReason.TransferFailed,
             );
         });
 
@@ -505,8 +513,9 @@ describe('Exchange core', () => {
                 }),
                 constants.AWAIT_TRANSACTION_MINED_MS,
             );
-            return expectRevertOrAlwaysFailingTransactionAsync(
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
                 exchangeWrapper.fillOrderAsync(signedOrder, takerAddress),
+                RevertReason.TransferFailed,
             );
         });
 
@@ -514,16 +523,18 @@ describe('Exchange core', () => {
             signedOrder = orderFactory.newSignedOrder({
                 expirationTimeSeconds: new BigNumber(Math.floor((Date.now() - 10000) / 1000)),
             });
-            return expectRevertOrAlwaysFailingTransactionAsync(
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
                 exchangeWrapper.fillOrderAsync(signedOrder, takerAddress),
+                RevertReason.OrderUnfillable,
             );
         });
 
         it('should throw if no value is filled', async () => {
             signedOrder = orderFactory.newSignedOrder();
             await exchangeWrapper.fillOrderAsync(signedOrder, takerAddress);
-            return expectRevertOrAlwaysFailingTransactionAsync(
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
                 exchangeWrapper.fillOrderAsync(signedOrder, takerAddress),
+                RevertReason.OrderUnfillable,
             );
         });
     });
@@ -535,8 +546,9 @@ describe('Exchange core', () => {
         });
 
         it('should throw if not sent by maker', async () => {
-            return expectRevertOrAlwaysFailingTransactionAsync(
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
                 exchangeWrapper.cancelOrderAsync(signedOrder, takerAddress),
+                RevertReason.InvalidMaker,
             );
         });
 
@@ -545,8 +557,9 @@ describe('Exchange core', () => {
                 makerAssetAmount: new BigNumber(0),
             });
 
-            return expectRevertOrAlwaysFailingTransactionAsync(
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
                 exchangeWrapper.cancelOrderAsync(signedOrder, makerAddress),
+                RevertReason.OrderUnfillable,
             );
         });
 
@@ -555,17 +568,19 @@ describe('Exchange core', () => {
                 takerAssetAmount: new BigNumber(0),
             });
 
-            return expectRevertOrAlwaysFailingTransactionAsync(
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
                 exchangeWrapper.cancelOrderAsync(signedOrder, makerAddress),
+                RevertReason.OrderUnfillable,
             );
         });
 
         it('should be able to cancel a full order', async () => {
             await exchangeWrapper.cancelOrderAsync(signedOrder, makerAddress);
-            return expectRevertOrAlwaysFailingTransactionAsync(
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
                 exchangeWrapper.fillOrderAsync(signedOrder, takerAddress, {
                     takerAssetFillAmount: signedOrder.takerAssetAmount.div(2),
                 }),
+                RevertReason.OrderUnfillable,
             );
         });
 
@@ -586,8 +601,9 @@ describe('Exchange core', () => {
 
         it('should throw if already cancelled', async () => {
             await exchangeWrapper.cancelOrderAsync(signedOrder, makerAddress);
-            return expectRevertOrAlwaysFailingTransactionAsync(
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
                 exchangeWrapper.cancelOrderAsync(signedOrder, makerAddress),
+                RevertReason.OrderUnfillable,
             );
         });
 
@@ -595,8 +611,9 @@ describe('Exchange core', () => {
             signedOrder = orderFactory.newSignedOrder({
                 expirationTimeSeconds: new BigNumber(Math.floor((Date.now() - 10000) / 1000)),
             });
-            return expectRevertOrAlwaysFailingTransactionAsync(
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
                 exchangeWrapper.cancelOrderAsync(signedOrder, makerAddress),
+                RevertReason.OrderUnfillable,
             );
         });
 
@@ -612,10 +629,11 @@ describe('Exchange core', () => {
             });
 
             const fillTakerAssetAmount2 = new BigNumber(1);
-            return expectRevertOrAlwaysFailingTransactionAsync(
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
                 exchangeWrapper.fillOrderAsync(signedOrder, takerAddress, {
                     takerAssetFillAmount: fillTakerAssetAmount2,
                 }),
+                RevertReason.RoundingError,
             );
         });
     });
@@ -625,16 +643,18 @@ describe('Exchange core', () => {
             const orderEpoch = new BigNumber(1);
             await exchangeWrapper.cancelOrdersUpToAsync(orderEpoch, makerAddress);
             const lesserOrderEpoch = new BigNumber(0);
-            return expectRevertOrAlwaysFailingTransactionAsync(
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
                 exchangeWrapper.cancelOrdersUpToAsync(lesserOrderEpoch, makerAddress),
+                RevertReason.InvalidNewOrderEpoch,
             );
         });
 
         it('should fail to set orderEpoch equal to existing orderEpoch', async () => {
             const orderEpoch = new BigNumber(1);
             await exchangeWrapper.cancelOrdersUpToAsync(orderEpoch, makerAddress);
-            return expectRevertOrAlwaysFailingTransactionAsync(
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
                 exchangeWrapper.cancelOrdersUpToAsync(orderEpoch, makerAddress),
+                RevertReason.InvalidNewOrderEpoch,
             );
         });
 
@@ -748,8 +768,9 @@ describe('Exchange core', () => {
             expect(initialOwnerTakerAsset).to.be.bignumber.equal(takerAddress);
             // Call Exchange
             const takerAssetFillAmount = signedOrder.takerAssetAmount;
-            return expectRevertOrAlwaysFailingTransactionAsync(
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
                 exchangeWrapper.fillOrderAsync(signedOrder, takerAddress, { takerAssetFillAmount }),
+                RevertReason.TransferFailed,
             );
         });
 
@@ -770,8 +791,9 @@ describe('Exchange core', () => {
             expect(initialOwnerTakerAsset).to.be.bignumber.not.equal(takerAddress);
             // Call Exchange
             const takerAssetFillAmount = signedOrder.takerAssetAmount;
-            return expectRevertOrAlwaysFailingTransactionAsync(
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
                 exchangeWrapper.fillOrderAsync(signedOrder, takerAddress, { takerAssetFillAmount }),
+                RevertReason.TransferFailed,
             );
         });
 
@@ -792,8 +814,9 @@ describe('Exchange core', () => {
             expect(initialOwnerTakerAsset).to.be.bignumber.equal(takerAddress);
             // Call Exchange
             const takerAssetFillAmount = signedOrder.takerAssetAmount;
-            return expectRevertOrAlwaysFailingTransactionAsync(
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
                 exchangeWrapper.fillOrderAsync(signedOrder, takerAddress, { takerAssetFillAmount }),
+                RevertReason.InvalidAmount,
             );
         });
 
@@ -814,19 +837,40 @@ describe('Exchange core', () => {
             expect(initialOwnerTakerAsset).to.be.bignumber.equal(takerAddress);
             // Call Exchange
             const takerAssetFillAmount = signedOrder.takerAssetAmount;
-            return expectRevertOrAlwaysFailingTransactionAsync(
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
                 exchangeWrapper.fillOrderAsync(signedOrder, takerAddress, { takerAssetFillAmount }),
+                RevertReason.InvalidAmount,
             );
         });
 
         it('should throw on partial fill', async () => {
             // Construct Exchange parameters
             const makerAssetId = erc721MakerAssetIds[0];
-            const takerAssetId = erc721TakerAssetIds[0];
             signedOrder = orderFactory.newSignedOrder({
                 makerAssetAmount: new BigNumber(1),
-                takerAssetAmount: new BigNumber(0),
+                takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(100), 18),
                 makerAssetData: assetProxyUtils.encodeERC721AssetData(erc721Token.address, makerAssetId),
+                takerAssetData: assetProxyUtils.encodeERC20AssetData(defaultTakerAssetAddress),
+            });
+            // Call Exchange
+            const takerAssetFillAmount = signedOrder.takerAssetAmount.div(2);
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
+                exchangeWrapper.fillOrderAsync(signedOrder, takerAddress, { takerAssetFillAmount }),
+                RevertReason.RoundingError,
+            );
+        });
+
+        it('should throw if assetData has a length < 132', async () => {
+            // Construct Exchange parameters
+            const makerAssetId = erc721MakerAssetIds[0];
+            const takerAssetId = erc721TakerAssetIds[0];
+            const makerAssetData = assetProxyUtils
+                .encodeERC721AssetData(erc721Token.address, makerAssetId)
+                .slice(0, -2);
+            signedOrder = orderFactory.newSignedOrder({
+                makerAssetAmount: new BigNumber(1),
+                takerAssetAmount: new BigNumber(1),
+                makerAssetData,
                 takerAssetData: assetProxyUtils.encodeERC721AssetData(erc721Token.address, takerAssetId),
             });
             // Verify pre-conditions
@@ -836,8 +880,9 @@ describe('Exchange core', () => {
             expect(initialOwnerTakerAsset).to.be.bignumber.equal(takerAddress);
             // Call Exchange
             const takerAssetFillAmount = signedOrder.takerAssetAmount;
-            return expectRevertOrAlwaysFailingTransactionAsync(
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
                 exchangeWrapper.fillOrderAsync(signedOrder, takerAddress, { takerAssetFillAmount }),
+                RevertReason.LengthGreaterThan131Required,
             );
         });
 
diff --git a/packages/contracts/test/exchange/dispatcher.ts b/packages/contracts/test/exchange/dispatcher.ts
index abbfd7ac7..8adbee6a3 100644
--- a/packages/contracts/test/exchange/dispatcher.ts
+++ b/packages/contracts/test/exchange/dispatcher.ts
@@ -1,6 +1,6 @@
 import { BlockchainLifecycle } from '@0xproject/dev-utils';
 import { assetProxyUtils } from '@0xproject/order-utils';
-import { AssetProxyId } from '@0xproject/types';
+import { AssetProxyId, RevertReason } from '@0xproject/types';
 import { BigNumber } from '@0xproject/utils';
 import * as chai from 'chai';
 
@@ -9,7 +9,7 @@ import { ERC20ProxyContract } from '../../src/generated_contract_wrappers/e_r_c2
 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 { expectRevertReasonOrAlwaysFailingTransactionAsync } from '../../src/utils/assertions';
 import { chaiSetup } from '../../src/utils/chai_setup';
 import { constants } from '../../src/utils/constants';
 import { ERC20Wrapper } from '../../src/utils/erc20_wrapper';
@@ -175,13 +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 expectRevertOrAlwaysFailingTransactionAsync(
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
                 assetProxyDispatcher.registerAssetProxy.sendTransactionAsync(
                     AssetProxyId.ERC20,
                     erc20Proxy.address,
                     constants.NULL_ADDRESS,
                     { from: owner },
                 ),
+                RevertReason.AssetProxyMismatch,
             );
         });
 
@@ -216,25 +217,27 @@ describe('AssetProxyDispatcher', () => {
 
         it('should throw if requesting address is not owner', async () => {
             const prevProxyAddress = constants.NULL_ADDRESS;
-            return expectRevertOrAlwaysFailingTransactionAsync(
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
                 assetProxyDispatcher.registerAssetProxy.sendTransactionAsync(
                     AssetProxyId.ERC20,
                     erc20Proxy.address,
                     prevProxyAddress,
                     { from: notOwner },
                 ),
+                RevertReason.OnlyContractOwner,
             );
         });
 
         it('should throw if attempting to register a proxy to the incorrect id', async () => {
             const prevProxyAddress = constants.NULL_ADDRESS;
-            return expectRevertOrAlwaysFailingTransactionAsync(
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
                 assetProxyDispatcher.registerAssetProxy.sendTransactionAsync(
                     AssetProxyId.ERC721,
                     erc20Proxy.address,
                     prevProxyAddress,
                     { from: owner },
                 ),
+                RevertReason.AssetProxyIdMismatch,
             );
         });
     });
@@ -276,14 +279,13 @@ describe('AssetProxyDispatcher', () => {
             );
             // Construct metadata for ERC20 proxy
             const encodedAssetData = assetProxyUtils.encodeERC20AssetData(zrxToken.address);
-            const encodedAssetDataWithoutProxyId = encodedAssetData.slice(0, -2);
+
             // Perform a transfer from makerAddress to takerAddress
             const erc20Balances = await erc20Wrapper.getBalancesAsync();
             const amount = new BigNumber(10);
             await web3Wrapper.awaitTransactionSuccessAsync(
                 await assetProxyDispatcher.publicDispatchTransferFrom.sendTransactionAsync(
-                    encodedAssetDataWithoutProxyId,
-                    AssetProxyId.ERC20,
+                    encodedAssetData,
                     makerAddress,
                     takerAddress,
                     amount,
@@ -304,18 +306,17 @@ describe('AssetProxyDispatcher', () => {
         it('should throw if dispatching to unregistered proxy', async () => {
             // Construct metadata for ERC20 proxy
             const encodedAssetData = assetProxyUtils.encodeERC20AssetData(zrxToken.address);
-            const encodedAssetDataWithoutProxyId = encodedAssetData.slice(0, -2);
             // Perform a transfer from makerAddress to takerAddress
             const amount = new BigNumber(10);
-            return expectRevertOrAlwaysFailingTransactionAsync(
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
                 assetProxyDispatcher.publicDispatchTransferFrom.sendTransactionAsync(
-                    encodedAssetDataWithoutProxyId,
-                    AssetProxyId.ERC20,
+                    encodedAssetData,
                     makerAddress,
                     takerAddress,
                     amount,
                     { from: owner },
                 ),
+                RevertReason.AssetProxyDoesNotExist,
             );
         });
     });
diff --git a/packages/contracts/test/exchange/match_orders.ts b/packages/contracts/test/exchange/match_orders.ts
index b8dca04fd..bcf691471 100644
--- a/packages/contracts/test/exchange/match_orders.ts
+++ b/packages/contracts/test/exchange/match_orders.ts
@@ -1,6 +1,6 @@
 import { BlockchainLifecycle } from '@0xproject/dev-utils';
 import { assetProxyUtils } from '@0xproject/order-utils';
-import { AssetProxyId } from '@0xproject/types';
+import { AssetProxyId, RevertReason } from '@0xproject/types';
 import { BigNumber } from '@0xproject/utils';
 import { Web3Wrapper } from '@0xproject/web3-wrapper';
 import * as chai from 'chai';
@@ -12,7 +12,7 @@ import { ERC20ProxyContract } from '../../src/generated_contract_wrappers/e_r_c2
 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 { expectRevertReasonOrAlwaysFailingTransactionAsync } from '../../src/utils/assertions';
 import { chaiSetup } from '../../src/utils/chai_setup';
 import { constants } from '../../src/utils/constants';
 import { ERC20Wrapper } from '../../src/utils/erc20_wrapper';
@@ -96,7 +96,7 @@ describe('matchOrders', () => {
             artifacts.Exchange,
             provider,
             txDefaults,
-            zrxToken.address,
+            assetProxyUtils.encodeERC20AssetData(zrxToken.address),
         );
         exchangeWrapper = new ExchangeWrapper(exchange, provider);
         await exchangeWrapper.registerAssetProxyAsync(AssetProxyId.ERC20, erc20Proxy.address, owner);
@@ -598,8 +598,9 @@ describe('matchOrders', () => {
             // Cancel left order
             await exchangeWrapper.cancelOrderAsync(signedOrderLeft, signedOrderLeft.makerAddress);
             // Match orders
-            return expectRevertOrAlwaysFailingTransactionAsync(
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
                 exchangeWrapper.matchOrdersAsync(signedOrderLeft, signedOrderRight, takerAddress),
+                RevertReason.OrderUnfillable,
             );
         });
 
@@ -622,8 +623,9 @@ describe('matchOrders', () => {
             // Cancel right order
             await exchangeWrapper.cancelOrderAsync(signedOrderRight, signedOrderRight.makerAddress);
             // Match orders
-            return expectRevertOrAlwaysFailingTransactionAsync(
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
                 exchangeWrapper.matchOrdersAsync(signedOrderLeft, signedOrderRight, takerAddress),
+                RevertReason.OrderUnfillable,
             );
         });
 
@@ -644,7 +646,7 @@ describe('matchOrders', () => {
                 feeRecipientAddress: feeRecipientAddressRight,
             });
             // Match orders
-            return expectRevertOrAlwaysFailingTransactionAsync(
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
                 matchOrderTester.matchOrdersAndVerifyBalancesAsync(
                     signedOrderLeft,
                     signedOrderRight,
@@ -652,6 +654,7 @@ describe('matchOrders', () => {
                     erc20BalancesByOwner,
                     erc721TokenIdsByOwner,
                 ),
+                RevertReason.NegativeSpreadRequired,
             );
         });
 
@@ -672,7 +675,7 @@ describe('matchOrders', () => {
                 feeRecipientAddress: feeRecipientAddressRight,
             });
             // Match orders
-            return expectRevertOrAlwaysFailingTransactionAsync(
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
                 matchOrderTester.matchOrdersAndVerifyBalancesAsync(
                     signedOrderLeft,
                     signedOrderRight,
@@ -680,6 +683,11 @@ describe('matchOrders', () => {
                     erc20BalancesByOwner,
                     erc721TokenIdsByOwner,
                 ),
+                // We are assuming assetData fields of the right order are the
+                // reverse of the left order, rather than checking equality. This
+                // saves a bunch of gas, but as a result if the assetData fields are
+                // off then the failure ends up happening at signature validation
+                RevertReason.InvalidOrderSignature,
             );
         });
 
@@ -702,7 +710,7 @@ describe('matchOrders', () => {
                 feeRecipientAddress: feeRecipientAddressRight,
             });
             // Match orders
-            return expectRevertOrAlwaysFailingTransactionAsync(
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
                 matchOrderTester.matchOrdersAndVerifyBalancesAsync(
                     signedOrderLeft,
                     signedOrderRight,
@@ -710,6 +718,7 @@ describe('matchOrders', () => {
                     erc20BalancesByOwner,
                     erc721TokenIdsByOwner,
                 ),
+                RevertReason.InvalidOrderSignature,
             );
         });
 
diff --git a/packages/contracts/test/exchange/signature_validator.ts b/packages/contracts/test/exchange/signature_validator.ts
index 8e221e3f1..21cc343b3 100644
--- a/packages/contracts/test/exchange/signature_validator.ts
+++ b/packages/contracts/test/exchange/signature_validator.ts
@@ -1,6 +1,6 @@
 import { BlockchainLifecycle } from '@0xproject/dev-utils';
 import { addSignedMessagePrefix, assetProxyUtils, MessagePrefixType, orderHashUtils } from '@0xproject/order-utils';
-import { SignatureType, SignedOrder } from '@0xproject/types';
+import { RevertReason, SignatureType, SignedOrder } from '@0xproject/types';
 import * as chai from 'chai';
 import { LogWithDecodedArgs } from 'ethereum-types';
 import ethUtil = require('ethereumjs-util');
@@ -107,7 +107,7 @@ describe('MixinSignatureValidator', () => {
                     signedOrder.makerAddress,
                     emptySignature,
                 ),
-                constants.EXCHANGE_LENGTH_GREATER_THAN_0_REQUIRED,
+                RevertReason.LengthGreaterThan0Required,
             );
         });
 
@@ -121,7 +121,7 @@ describe('MixinSignatureValidator', () => {
                     signedOrder.makerAddress,
                     unsupportedSignatureHex,
                 ),
-                constants.EXCHANGE_SIGNATURE_UNSUPPORTED,
+                RevertReason.SignatureUnsupported,
             );
         });
 
@@ -134,7 +134,7 @@ describe('MixinSignatureValidator', () => {
                     signedOrder.makerAddress,
                     unsupportedSignatureHex,
                 ),
-                constants.EXCHANGE_SIGNATURE_ILLEGAL,
+                RevertReason.SignatureIllegal,
             );
         });
 
@@ -161,7 +161,7 @@ describe('MixinSignatureValidator', () => {
                     signedOrder.makerAddress,
                     signatureHex,
                 ),
-                constants.EXCHANGE_LENGTH_0_REQUIRED,
+                RevertReason.Length0Required,
             );
         });
 
diff --git a/packages/contracts/test/exchange/transactions.ts b/packages/contracts/test/exchange/transactions.ts
index 9a625880c..b0c08e46e 100644
--- a/packages/contracts/test/exchange/transactions.ts
+++ b/packages/contracts/test/exchange/transactions.ts
@@ -1,6 +1,6 @@
 import { BlockchainLifecycle } from '@0xproject/dev-utils';
 import { assetProxyUtils, generatePseudoRandomSalt } from '@0xproject/order-utils';
-import { AssetProxyId, OrderWithoutExchangeAddress, SignedOrder } from '@0xproject/types';
+import { AssetProxyId, OrderWithoutExchangeAddress, RevertReason, SignedOrder } from '@0xproject/types';
 import { BigNumber } from '@0xproject/utils';
 import * as chai from 'chai';
 
@@ -10,7 +10,7 @@ import { ExchangeContract } from '../../src/generated_contract_wrappers/exchange
 import { ExchangeWrapperContract } from '../../src/generated_contract_wrappers/exchange_wrapper';
 import { WhitelistContract } from '../../src/generated_contract_wrappers/whitelist';
 import { artifacts } from '../../src/utils/artifacts';
-import { expectRevertOrAlwaysFailingTransactionAsync } from '../../src/utils/assertions';
+import { expectRevertReasonOrAlwaysFailingTransactionAsync } from '../../src/utils/assertions';
 import { chaiSetup } from '../../src/utils/chai_setup';
 import { constants } from '../../src/utils/constants';
 import { ERC20Wrapper } from '../../src/utils/erc20_wrapper';
@@ -59,6 +59,12 @@ describe('Exchange transactions', () => {
     after(async () => {
         await blockchainLifecycle.revertAsync();
     });
+    beforeEach(async () => {
+        await blockchainLifecycle.startAsync();
+    });
+    afterEach(async () => {
+        await blockchainLifecycle.revertAsync();
+    });
     before(async () => {
         const accounts = await web3Wrapper.getAvailableAddressesAsync();
         const usedAddresses = ([owner, senderAddress, makerAddress, takerAddress, feeRecipientAddress] = accounts);
@@ -73,7 +79,7 @@ describe('Exchange transactions', () => {
             artifacts.Exchange,
             provider,
             txDefaults,
-            zrxToken.address,
+            assetProxyUtils.encodeERC20AssetData(zrxToken.address),
         );
         exchangeWrapper = new ExchangeWrapper(exchange, provider);
         await exchangeWrapper.registerAssetProxyAsync(AssetProxyId.ERC20, erc20Proxy.address, owner);
@@ -101,13 +107,6 @@ describe('Exchange transactions', () => {
         makerTransactionFactory = new TransactionFactory(makerPrivateKey, exchange.address);
         takerTransactionFactory = new TransactionFactory(takerPrivateKey, exchange.address);
     });
-    beforeEach(async () => {
-        await blockchainLifecycle.startAsync();
-    });
-    afterEach(async () => {
-        await blockchainLifecycle.revertAsync();
-    });
-
     describe('executeTransaction', () => {
         describe('fillOrder', () => {
             let takerAssetFillAmount: BigNumber;
@@ -126,8 +125,9 @@ describe('Exchange transactions', () => {
             });
 
             it('should throw if not called by specified sender', async () => {
-                return expectRevertOrAlwaysFailingTransactionAsync(
+                return expectRevertReasonOrAlwaysFailingTransactionAsync(
                     exchangeWrapper.executeTransactionAsync(signedTx, takerAddress),
+                    RevertReason.FailedExecution,
                 );
             });
 
@@ -168,8 +168,9 @@ describe('Exchange transactions', () => {
 
             it('should throw if the a 0x transaction with the same transactionHash has already been executed', async () => {
                 await exchangeWrapper.executeTransactionAsync(signedTx, senderAddress);
-                return expectRevertOrAlwaysFailingTransactionAsync(
+                return expectRevertReasonOrAlwaysFailingTransactionAsync(
                     exchangeWrapper.executeTransactionAsync(signedTx, senderAddress),
+                    RevertReason.InvalidTxHash,
                 );
             });
 
@@ -187,15 +188,17 @@ describe('Exchange transactions', () => {
             });
 
             it('should throw if not called by specified sender', async () => {
-                return expectRevertOrAlwaysFailingTransactionAsync(
+                return expectRevertReasonOrAlwaysFailingTransactionAsync(
                     exchangeWrapper.executeTransactionAsync(signedTx, makerAddress),
+                    RevertReason.FailedExecution,
                 );
             });
 
             it('should cancel the order when signed by maker and called by sender', async () => {
                 await exchangeWrapper.executeTransactionAsync(signedTx, senderAddress);
-                return expectRevertOrAlwaysFailingTransactionAsync(
+                return expectRevertReasonOrAlwaysFailingTransactionAsync(
                     exchangeWrapper.fillOrderAsync(signedOrder, senderAddress),
+                    RevertReason.OrderUnfillable,
                 );
             });
         });
@@ -238,7 +241,7 @@ describe('Exchange transactions', () => {
                     signedOrder.signature,
                 );
                 const signedFillTx = takerTransactionFactory.newSignedTransaction(fillData);
-                return expectRevertOrAlwaysFailingTransactionAsync(
+                return expectRevertReasonOrAlwaysFailingTransactionAsync(
                     exchangeWrapperContract.fillOrder.sendTransactionAsync(
                         orderWithoutExchangeAddress,
                         takerAssetFillAmount,
@@ -247,6 +250,7 @@ describe('Exchange transactions', () => {
                         signedFillTx.signature,
                         { from: takerAddress },
                     ),
+                    RevertReason.FailedExecution,
                 );
             });
 
@@ -357,7 +361,7 @@ describe('Exchange transactions', () => {
             orderWithoutExchangeAddress = orderUtils.getOrderWithoutExchangeAddress(signedOrder);
             const takerAssetFillAmount = signedOrder.takerAssetAmount;
             const salt = generatePseudoRandomSalt();
-            return expectRevertOrAlwaysFailingTransactionAsync(
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
                 whitelist.fillOrderIfWhitelisted.sendTransactionAsync(
                     orderWithoutExchangeAddress,
                     takerAssetFillAmount,
@@ -365,6 +369,7 @@ describe('Exchange transactions', () => {
                     signedOrder.signature,
                     { from: takerAddress },
                 ),
+                RevertReason.MakerNotWhitelisted,
             );
         });
 
@@ -378,7 +383,7 @@ describe('Exchange transactions', () => {
             orderWithoutExchangeAddress = orderUtils.getOrderWithoutExchangeAddress(signedOrder);
             const takerAssetFillAmount = signedOrder.takerAssetAmount;
             const salt = generatePseudoRandomSalt();
-            return expectRevertOrAlwaysFailingTransactionAsync(
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
                 whitelist.fillOrderIfWhitelisted.sendTransactionAsync(
                     orderWithoutExchangeAddress,
                     takerAssetFillAmount,
@@ -386,6 +391,7 @@ describe('Exchange transactions', () => {
                     signedOrder.signature,
                     { from: takerAddress },
                 ),
+                RevertReason.TakerNotWhitelisted,
             );
         });
 
diff --git a/packages/contracts/test/exchange/wrapper.ts b/packages/contracts/test/exchange/wrapper.ts
index 703f644b8..9ee68f94d 100644
--- a/packages/contracts/test/exchange/wrapper.ts
+++ b/packages/contracts/test/exchange/wrapper.ts
@@ -1,6 +1,6 @@
 import { BlockchainLifecycle } from '@0xproject/dev-utils';
 import { assetProxyUtils } from '@0xproject/order-utils';
-import { AssetProxyId, SignedOrder } from '@0xproject/types';
+import { AssetProxyId, RevertReason, SignedOrder } from '@0xproject/types';
 import { BigNumber } from '@0xproject/utils';
 import { Web3Wrapper } from '@0xproject/web3-wrapper';
 import * as chai from 'chai';
@@ -12,7 +12,7 @@ import { ERC20ProxyContract } from '../../src/generated_contract_wrappers/e_r_c2
 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 { expectRevertReasonOrAlwaysFailingTransactionAsync } from '../../src/utils/assertions';
 import { chaiSetup } from '../../src/utils/chai_setup';
 import { constants } from '../../src/utils/constants';
 import { ERC20Wrapper } from '../../src/utils/erc20_wrapper';
@@ -80,7 +80,7 @@ describe('Exchange wrappers', () => {
             artifacts.Exchange,
             provider,
             txDefaults,
-            zrxToken.address,
+            assetProxyUtils.encodeERC20AssetData(zrxToken.address),
         );
         exchangeWrapper = new ExchangeWrapper(exchange, provider);
         await exchangeWrapper.registerAssetProxyAsync(AssetProxyId.ERC20, erc20Proxy.address, owner);
@@ -165,13 +165,14 @@ describe('Exchange wrappers', () => {
             );
         });
 
-        it('should throw if an signedOrder is expired', async () => {
+        it('should throw if a signedOrder is expired', async () => {
             const signedOrder = orderFactory.newSignedOrder({
                 expirationTimeSeconds: new BigNumber(Math.floor((Date.now() - 10000) / 1000)),
             });
 
-            return expectRevertOrAlwaysFailingTransactionAsync(
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
                 exchangeWrapper.fillOrKillOrderAsync(signedOrder, takerAddress),
+                RevertReason.OrderUnfillable,
             );
         });
 
@@ -182,8 +183,9 @@ describe('Exchange wrappers', () => {
                 takerAssetFillAmount: signedOrder.takerAssetAmount.div(2),
             });
 
-            return expectRevertOrAlwaysFailingTransactionAsync(
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
                 exchangeWrapper.fillOrKillOrderAsync(signedOrder, takerAddress),
+                RevertReason.CompleteFillFailed,
             );
         });
     });
@@ -494,10 +496,11 @@ describe('Exchange wrappers', () => {
 
                 await exchangeWrapper.fillOrKillOrderAsync(signedOrders[0], takerAddress);
 
-                return expectRevertOrAlwaysFailingTransactionAsync(
+                return expectRevertReasonOrAlwaysFailingTransactionAsync(
                     exchangeWrapper.batchFillOrKillOrdersAsync(signedOrders, takerAddress, {
                         takerAssetFillAmounts,
                     }),
+                    RevertReason.OrderUnfillable,
                 );
             });
         });
@@ -687,7 +690,7 @@ describe('Exchange wrappers', () => {
                 expect(newBalances).to.be.deep.equal(erc20Balances);
             });
 
-            it('should throw when an signedOrder does not use the same takerAssetAddress', async () => {
+            it('should throw when a signedOrder does not use the same takerAssetAddress', async () => {
                 signedOrders = [
                     orderFactory.newSignedOrder(),
                     orderFactory.newSignedOrder({
@@ -696,10 +699,13 @@ describe('Exchange wrappers', () => {
                     orderFactory.newSignedOrder(),
                 ];
 
-                return expectRevertOrAlwaysFailingTransactionAsync(
+                return expectRevertReasonOrAlwaysFailingTransactionAsync(
                     exchangeWrapper.marketSellOrdersAsync(signedOrders, takerAddress, {
                         takerAssetFillAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(1000), 18),
                     }),
+                    // We simply use the takerAssetData from the first order for all orders.
+                    // If they are not the same, the contract throws when validating the order signature
+                    RevertReason.InvalidOrderSignature,
                 );
             });
         });
@@ -902,7 +908,7 @@ describe('Exchange wrappers', () => {
                 expect(newBalances).to.be.deep.equal(erc20Balances);
             });
 
-            it('should throw when an signedOrder does not use the same makerAssetAddress', async () => {
+            it('should throw when a signedOrder does not use the same makerAssetAddress', async () => {
                 signedOrders = [
                     orderFactory.newSignedOrder(),
                     orderFactory.newSignedOrder({
@@ -911,10 +917,11 @@ describe('Exchange wrappers', () => {
                     orderFactory.newSignedOrder(),
                 ];
 
-                return expectRevertOrAlwaysFailingTransactionAsync(
+                return expectRevertReasonOrAlwaysFailingTransactionAsync(
                     exchangeWrapper.marketBuyOrdersAsync(signedOrders, takerAddress, {
                         makerAssetFillAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(1000), 18),
                     }),
+                    RevertReason.InvalidOrderSignature,
                 );
             });
         });
diff --git a/packages/contracts/test/libraries/lib_bytes.ts b/packages/contracts/test/libraries/lib_bytes.ts
index a31a4789c..3d4058cbc 100644
--- a/packages/contracts/test/libraries/lib_bytes.ts
+++ b/packages/contracts/test/libraries/lib_bytes.ts
@@ -1,5 +1,6 @@
 import { BlockchainLifecycle } from '@0xproject/dev-utils';
 import { assetProxyUtils, generatePseudoRandomSalt } from '@0xproject/order-utils';
+import { RevertReason } from '@0xproject/types';
 import { BigNumber } from '@0xproject/utils';
 import BN = require('bn.js');
 import * as chai from 'chai';
@@ -17,6 +18,12 @@ chaiSetup.configure();
 const expect = chai.expect;
 const blockchainLifecycle = new BlockchainLifecycle(web3Wrapper);
 
+// 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('LibBytes', () => {
     let libBytes: TestLibBytesContract;
     const byteArrayShorterThan32Bytes = '0x012345';
@@ -95,7 +102,7 @@ describe('LibBytes', () => {
         it('should revert if length is 0', async () => {
             return expectRevertOrOtherErrorAsync(
                 libBytes.publicPopLastByte.callAsync(constants.NULL_BYTES),
-                constants.LIB_BYTES_GREATER_THAN_ZERO_LENGTH_REQUIRED,
+                RevertReason.LibBytesGreaterThanZeroLengthRequired,
             );
         });
         it('should pop the last byte from the input and return it', async () => {
@@ -111,7 +118,7 @@ describe('LibBytes', () => {
         it('should revert if length is less than 20', async () => {
             return expectRevertOrOtherErrorAsync(
                 libBytes.publicPopLast20Bytes.callAsync(byteArrayShorterThan20Bytes),
-                constants.LIB_BYTES_GREATER_OR_EQUAL_TO_20_LENGTH_REQUIRED,
+                RevertReason.LibBytesGreaterOrEqualTo20LengthRequired,
             );
         });
         it('should pop the last 20 bytes from the input and return it', async () => {
@@ -123,48 +130,55 @@ describe('LibBytes', () => {
         });
     });
 
-    describe('areBytesEqual', () => {
+    describe('equals', () => {
         it('should return true if byte arrays are equal (both arrays < 32 bytes)', async () => {
-            const areBytesEqual = await libBytes.publicAreBytesEqual.callAsync(
+            const isEqual = await libBytes.publicEquals.callAsync(
                 byteArrayShorterThan32Bytes,
                 byteArrayShorterThan32Bytes,
             );
-            return expect(areBytesEqual).to.be.true();
+            return expect(isEqual).to.be.true();
         });
         it('should return true if byte arrays are equal (both arrays > 32 bytes)', async () => {
-            const areBytesEqual = await libBytes.publicAreBytesEqual.callAsync(
+            const isEqual = await libBytes.publicEquals.callAsync(
                 byteArrayLongerThan32Bytes,
                 byteArrayLongerThan32Bytes,
             );
-            return expect(areBytesEqual).to.be.true();
+            return expect(isEqual).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(
+            const isEqual = await libBytes.publicEquals.callAsync(
                 byteArrayShorterThan32Bytes,
                 byteArrayLongerThan32Bytes,
             );
-            return expect(areBytesEqual).to.be.false();
+            return expect(isEqual).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(
+            const isEqual = await libBytes.publicEquals.callAsync(
                 byteArrayLongerThan32Bytes,
                 byteArrayShorterThan32Bytes,
             );
-            return expect(areBytesEqual).to.be.false();
+            return expect(isEqual).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(
+            const isEqual = await libBytes.publicEquals.callAsync(
                 byteArrayLongerThan32BytesFirstBytesSwapped,
                 byteArrayLongerThan32Bytes,
             );
-            return expect(areBytesEqual).to.be.false();
+            return expect(isEqual).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(
+            const isEqual = await libBytes.publicEquals.callAsync(
                 byteArrayLongerThan32BytesLastBytesSwapped,
                 byteArrayLongerThan32Bytes,
             );
-            return expect(areBytesEqual).to.be.false();
+            return expect(isEqual).to.be.false();
+        });
+
+        describe('should ignore trailing data', () => {
+            it('should return true when both < 32 bytes', async () => {
+                const isEqual = await libBytes.publicEqualsPop1.callAsync('0x0102', '0x0103');
+                return expect(isEqual).to.be.true();
+            });
         });
     });
 
@@ -172,7 +186,7 @@ describe('LibBytes', () => {
         it('should revert if dest is shorter than source', async () => {
             return expectRevertOrOtherErrorAsync(
                 libBytes.publicDeepCopyBytes.callAsync(byteArrayShorterThan32Bytes, byteArrayLongerThan32Bytes),
-                constants.LIB_BYTES_GREATER_OR_EQUAL_TO_SOURCE_BYTES_LENGTH_REQUIRED,
+                RevertReason.LibBytesGreaterOrEqualToSourceBytesLengthRequired,
             );
         });
         it('should overwrite dest with source if source and dest have equal length', async () => {
@@ -225,7 +239,7 @@ describe('LibBytes', () => {
             const offset = new BigNumber(0);
             return expectRevertOrOtherErrorAsync(
                 libBytes.publicReadAddress.callAsync(shortByteArray, offset),
-                constants.LIB_BYTES_GREATER_OR_EQUAL_TO_20_LENGTH_REQUIRED,
+                RevertReason.LibBytesGreaterOrEqualTo20LengthRequired,
             );
         });
         it('should fail if the length between the offset and end of the byte array is too short to hold an address', async () => {
@@ -233,7 +247,7 @@ describe('LibBytes', () => {
             const badOffset = new BigNumber(ethUtil.toBuffer(byteArray).byteLength);
             return expectRevertOrOtherErrorAsync(
                 libBytes.publicReadAddress.callAsync(byteArray, badOffset),
-                constants.LIB_BYTES_GREATER_OR_EQUAL_TO_20_LENGTH_REQUIRED,
+                RevertReason.LibBytesGreaterOrEqualTo20LengthRequired,
             );
         });
     });
@@ -269,7 +283,7 @@ describe('LibBytes', () => {
             const offset = new BigNumber(0);
             return expectRevertOrOtherErrorAsync(
                 libBytes.publicWriteAddress.callAsync(byteArrayShorterThan20Bytes, offset, testAddress),
-                constants.LIB_BYTES_GREATER_OR_EQUAL_TO_20_LENGTH_REQUIRED,
+                RevertReason.LibBytesGreaterOrEqualTo20LengthRequired,
             );
         });
         it('should fail if the length between the offset and end of the byte array is too short to hold an address', async () => {
@@ -277,7 +291,7 @@ describe('LibBytes', () => {
             const badOffset = new BigNumber(ethUtil.toBuffer(byteArray).byteLength);
             return expectRevertOrOtherErrorAsync(
                 libBytes.publicWriteAddress.callAsync(byteArray, badOffset, testAddress),
-                constants.LIB_BYTES_GREATER_OR_EQUAL_TO_20_LENGTH_REQUIRED,
+                RevertReason.LibBytesGreaterOrEqualTo20LengthRequired,
             );
         });
     });
@@ -301,14 +315,14 @@ describe('LibBytes', () => {
             const offset = new BigNumber(0);
             return expectRevertOrOtherErrorAsync(
                 libBytes.publicReadBytes32.callAsync(byteArrayShorterThan32Bytes, offset),
-                constants.LIB_BYTES_GREATER_OR_EQUAL_TO_32_LENGTH_REQUIRED,
+                RevertReason.LibBytesGreaterOrEqualTo32LengthRequired,
             );
         });
         it('should fail if the length between the offset and end of the byte array is too short to hold a bytes32', async () => {
             const badOffset = new BigNumber(ethUtil.toBuffer(testBytes32).byteLength);
             return expectRevertOrOtherErrorAsync(
                 libBytes.publicReadBytes32.callAsync(testBytes32, badOffset),
-                constants.LIB_BYTES_GREATER_OR_EQUAL_TO_32_LENGTH_REQUIRED,
+                RevertReason.LibBytesGreaterOrEqualTo32LengthRequired,
             );
         });
     });
@@ -344,7 +358,7 @@ describe('LibBytes', () => {
             const offset = new BigNumber(0);
             return expectRevertOrOtherErrorAsync(
                 libBytes.publicWriteBytes32.callAsync(byteArrayShorterThan32Bytes, offset, testBytes32),
-                constants.LIB_BYTES_GREATER_OR_EQUAL_TO_32_LENGTH_REQUIRED,
+                RevertReason.LibBytesGreaterOrEqualTo32LengthRequired,
             );
         });
         it('should fail if the length between the offset and end of the byte array is too short to hold a bytes32', async () => {
@@ -352,7 +366,7 @@ describe('LibBytes', () => {
             const badOffset = new BigNumber(ethUtil.toBuffer(byteArray).byteLength);
             return expectRevertOrOtherErrorAsync(
                 libBytes.publicWriteBytes32.callAsync(byteArray, badOffset, testBytes32),
-                constants.LIB_BYTES_GREATER_OR_EQUAL_TO_32_LENGTH_REQUIRED,
+                RevertReason.LibBytesGreaterOrEqualTo32LengthRequired,
             );
         });
     });
@@ -380,7 +394,7 @@ describe('LibBytes', () => {
             const offset = new BigNumber(0);
             return expectRevertOrOtherErrorAsync(
                 libBytes.publicReadUint256.callAsync(byteArrayShorterThan32Bytes, offset),
-                constants.LIB_BYTES_GREATER_OR_EQUAL_TO_32_LENGTH_REQUIRED,
+                RevertReason.LibBytesGreaterOrEqualTo32LengthRequired,
             );
         });
         it('should fail if the length between the offset and end of the byte array is too short to hold a uint256', async () => {
@@ -390,7 +404,7 @@ describe('LibBytes', () => {
             const badOffset = new BigNumber(testUint256AsBuffer.byteLength);
             return expectRevertOrOtherErrorAsync(
                 libBytes.publicReadUint256.callAsync(byteArray, badOffset),
-                constants.LIB_BYTES_GREATER_OR_EQUAL_TO_32_LENGTH_REQUIRED,
+                RevertReason.LibBytesGreaterOrEqualTo32LengthRequired,
             );
         });
     });
@@ -430,7 +444,7 @@ describe('LibBytes', () => {
             const offset = new BigNumber(0);
             return expectRevertOrOtherErrorAsync(
                 libBytes.publicWriteUint256.callAsync(byteArrayShorterThan32Bytes, offset, testUint256),
-                constants.LIB_BYTES_GREATER_OR_EQUAL_TO_32_LENGTH_REQUIRED,
+                RevertReason.LibBytesGreaterOrEqualTo32LengthRequired,
             );
         });
         it('should fail if the length between the offset and end of the byte array is too short to hold a uint256', async () => {
@@ -438,31 +452,31 @@ describe('LibBytes', () => {
             const badOffset = new BigNumber(ethUtil.toBuffer(byteArray).byteLength);
             return expectRevertOrOtherErrorAsync(
                 libBytes.publicWriteUint256.callAsync(byteArray, badOffset, testUint256),
-                constants.LIB_BYTES_GREATER_OR_EQUAL_TO_32_LENGTH_REQUIRED,
+                RevertReason.LibBytesGreaterOrEqualTo32LengthRequired,
             );
         });
     });
 
-    describe('readFirst4', () => {
+    describe('readBytes4', () => {
         // 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 expectRevertOrOtherErrorAsync(
-                libBytes.publicReadFirst4.callAsync(byteArrayLessThan4Bytes),
-                constants.LIB_BYTES_GREATER_OR_EQUAL_TO_4_LENGTH_REQUIRED,
+                libBytes.publicReadBytes4.callAsync(byteArrayLessThan4Bytes, new BigNumber(0)),
+                RevertReason.LibBytesGreaterOrEqualTo4LengthRequired,
             );
         });
         it('should return the first 4 bytes of a byte array of arbitrary length', async () => {
-            const first4Bytes = await libBytes.publicReadFirst4.callAsync(byteArrayLongerThan32Bytes);
+            const first4Bytes = await libBytes.publicReadBytes4.callAsync(byteArrayLongerThan32Bytes, new BigNumber(0));
             const expectedFirst4Bytes = byteArrayLongerThan32Bytes.slice(0, 10);
             expect(first4Bytes).to.equal(expectedFirst4Bytes);
         });
     });
 
-    describe('readBytes', () => {
+    describe('readBytesWithLength', () => {
         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);
+            const bytes = await libBytes.publicReadBytesWithLength.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 () => {
@@ -470,12 +484,12 @@ describe('LibBytes', () => {
             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);
+            const bytes = await libBytes.publicReadBytesWithLength.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);
+            const bytes = await libBytes.publicReadBytesWithLength.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 () => {
@@ -483,12 +497,12 @@ describe('LibBytes', () => {
             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);
+            const bytes = await libBytes.publicReadBytesWithLength.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);
+            const bytes = await libBytes.publicReadBytesWithLength.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 () => {
@@ -496,46 +510,50 @@ describe('LibBytes', () => {
             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);
+            const bytes = await libBytes.publicReadBytesWithLength.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,
+                libBytes.publicReadBytesWithLength.callAsync(byteArrayShorterThan32Bytes, offset),
+                RevertReason.LibBytesGreaterOrEqualTo32LengthRequired,
             );
         });
         it('should fail if we store a nested byte array length, without a nested byte array', async () => {
             const offset = new BigNumber(0);
             return expectRevertOrOtherErrorAsync(
-                libBytes.publicReadBytes.callAsync(testBytes32, offset),
-                constants.LIB_BYTES_GREATER_OR_EQUAL_TO_NESTED_BYTES_LENGTH_REQUIRED,
+                libBytes.publicReadBytesWithLength.callAsync(testBytes32, offset),
+                RevertReason.LibBytesGreaterOrEqualToNestedBytesLengthRequired,
             );
         });
         it('should fail if the length between the offset and end of the byte array is too short to hold the length of a nested byte array', async () => {
             const badOffset = new BigNumber(ethUtil.toBuffer(byteArrayShorterThan32Bytes).byteLength);
             return expectRevertOrOtherErrorAsync(
-                libBytes.publicReadBytes.callAsync(byteArrayShorterThan32Bytes, badOffset),
-                constants.LIB_BYTES_GREATER_OR_EQUAL_TO_32_LENGTH_REQUIRED,
+                libBytes.publicReadBytesWithLength.callAsync(byteArrayShorterThan32Bytes, badOffset),
+                RevertReason.LibBytesGreaterOrEqualTo32LengthRequired,
             );
         });
         it('should fail if the length between the offset and end of the byte array is too short to hold the nested byte array', async () => {
             const badOffset = new BigNumber(ethUtil.toBuffer(testBytes32).byteLength);
             return expectRevertOrOtherErrorAsync(
-                libBytes.publicReadBytes.callAsync(testBytes32, badOffset),
-                constants.LIB_BYTES_GREATER_OR_EQUAL_TO_32_LENGTH_REQUIRED,
+                libBytes.publicReadBytesWithLength.callAsync(testBytes32, badOffset),
+                RevertReason.LibBytesGreaterOrEqualTo32LengthRequired,
             );
         });
     });
 
-    describe('writeBytes', () => {
+    describe('writeBytesWithLength', () => {
         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);
+            const bytesWritten = await libBytes.publicWriteBytesWithLength.callAsync(
+                emptyByteArray,
+                testBytesOffset,
+                shortData,
+            );
+            const bytesRead = await libBytes.publicReadBytesWithLength.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 () => {
@@ -546,19 +564,31 @@ describe('LibBytes', () => {
             const emptyByteArray = ethUtil.bufferToHex(
                 new Buffer(prefixDataAsBuffer.byteLength + shortTestBytesAsBuffer.byteLength),
             );
-            let bytesWritten = await libBytes.publicWriteBytes.callAsync(emptyByteArray, prefixOffset, prefixData);
+            let bytesWritten = await libBytes.publicWriteBytesWithLength.callAsync(
+                emptyByteArray,
+                prefixOffset,
+                prefixData,
+            );
             // Write data after prefix
             const testBytesOffset = new BigNumber(prefixDataAsBuffer.byteLength);
-            bytesWritten = await libBytes.publicWriteBytes.callAsync(bytesWritten, testBytesOffset, shortData);
+            bytesWritten = await libBytes.publicWriteBytesWithLength.callAsync(
+                bytesWritten,
+                testBytesOffset,
+                shortData,
+            );
             // Read data after prefix and validate
-            const bytes = await libBytes.publicReadBytes.callAsync(bytesWritten, testBytesOffset);
+            const bytes = await libBytes.publicReadBytesWithLength.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);
+            const bytesWritten = await libBytes.publicWriteBytesWithLength.callAsync(
+                emptyByteArray,
+                testBytesOffset,
+                wordOfData,
+            );
+            const bytesRead = await libBytes.publicReadBytesWithLength.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 () => {
@@ -569,19 +599,31 @@ describe('LibBytes', () => {
             const emptyByteArray = ethUtil.bufferToHex(
                 new Buffer(prefixDataAsBuffer.byteLength + wordOfTestBytesAsBuffer.byteLength),
             );
-            let bytesWritten = await libBytes.publicWriteBytes.callAsync(emptyByteArray, prefixOffset, prefixData);
+            let bytesWritten = await libBytes.publicWriteBytesWithLength.callAsync(
+                emptyByteArray,
+                prefixOffset,
+                prefixData,
+            );
             // Write data after prefix
             const testBytesOffset = new BigNumber(prefixDataAsBuffer.byteLength);
-            bytesWritten = await libBytes.publicWriteBytes.callAsync(bytesWritten, testBytesOffset, wordOfData);
+            bytesWritten = await libBytes.publicWriteBytesWithLength.callAsync(
+                bytesWritten,
+                testBytesOffset,
+                wordOfData,
+            );
             // Read data after prefix and validate
-            const bytes = await libBytes.publicReadBytes.callAsync(bytesWritten, testBytesOffset);
+            const bytes = await libBytes.publicReadBytesWithLength.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);
+            const bytesWritten = await libBytes.publicWriteBytesWithLength.callAsync(
+                emptyByteArray,
+                testBytesOffset,
+                longData,
+            );
+            const bytesRead = await libBytes.publicReadBytesWithLength.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 () => {
@@ -592,30 +634,200 @@ describe('LibBytes', () => {
             const emptyByteArray = ethUtil.bufferToHex(
                 new Buffer(prefixDataAsBuffer.byteLength + longTestBytesAsBuffer.byteLength),
             );
-            let bytesWritten = await libBytes.publicWriteBytes.callAsync(emptyByteArray, prefixOffset, prefixData);
+            let bytesWritten = await libBytes.publicWriteBytesWithLength.callAsync(
+                emptyByteArray,
+                prefixOffset,
+                prefixData,
+            );
             // Write data after prefix
             const testBytesOffset = new BigNumber(prefixDataAsBuffer.byteLength);
-            bytesWritten = await libBytes.publicWriteBytes.callAsync(bytesWritten, testBytesOffset, longData);
+            bytesWritten = await libBytes.publicWriteBytesWithLength.callAsync(bytesWritten, testBytesOffset, longData);
             // Read data after prefix and validate
-            const bytes = await libBytes.publicReadBytes.callAsync(bytesWritten, testBytesOffset);
+            const bytes = await libBytes.publicReadBytesWithLength.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,
+                libBytes.publicWriteBytesWithLength.callAsync(emptyByteArray, offset, longData),
+                RevertReason.LibBytesGreaterOrEqualToNestedBytesLengthRequired,
             );
         });
         it('should fail if the length between the offset and end of the byte array is too short to hold the length of a nested byte array)', async () => {
             const 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,
+                libBytes.publicWriteBytesWithLength.callAsync(emptyByteArray, badOffset, shortData),
+                RevertReason.LibBytesGreaterOrEqualToNestedBytesLengthRequired,
             );
         });
     });
+
+    describe('memCopy', () => {
+        // Create memory 0x000102...FF
+        const memSize = 256;
+        // tslint:disable:no-shadowed-variable
+        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(mem).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 libBytes.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']]));
+    });
 });
 // tslint:disable:max-file-line-count
diff --git a/packages/contracts/test/libraries/lib_mem.ts b/packages/contracts/test/libraries/lib_mem.ts
deleted file mode 100644
index 00f7c4d8b..000000000
--- a/packages/contracts/test/libraries/lib_mem.ts
+++ /dev/null
@@ -1,190 +0,0 @@
-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/unlimited_allowance_token.ts b/packages/contracts/test/unlimited_allowance_token.ts
index 7132c57bf..0eb82b5fe 100644
--- a/packages/contracts/test/unlimited_allowance_token.ts
+++ b/packages/contracts/test/unlimited_allowance_token.ts
@@ -1,4 +1,5 @@
 import { BlockchainLifecycle } from '@0xproject/dev-utils';
+import { RevertReason } from '@0xproject/types';
 import { BigNumber } from '@0xproject/utils';
 import * as chai from 'chai';
 
@@ -55,7 +56,7 @@ describe('UnlimitedAllowanceToken', () => {
             const amountToTransfer = ownerBalance.plus(1);
             return expectRevertOrOtherErrorAsync(
                 token.transfer.callAsync(spender, amountToTransfer, { from: owner }),
-                constants.ERC20_INSUFFICIENT_BALANCE,
+                RevertReason.Erc20InsufficientBalance,
             );
         });
 
@@ -96,7 +97,7 @@ describe('UnlimitedAllowanceToken', () => {
                 token.transferFrom.callAsync(owner, spender, amountToTransfer, {
                     from: spender,
                 }),
-                constants.ERC20_INSUFFICIENT_BALANCE,
+                RevertReason.Erc20InsufficientBalance,
             );
         });
 
@@ -112,7 +113,7 @@ describe('UnlimitedAllowanceToken', () => {
                 token.transferFrom.callAsync(owner, spender, amountToTransfer, {
                     from: spender,
                 }),
-                constants.ERC20_INSUFFICIENT_ALLOWANCE,
+                RevertReason.Erc20InsufficientAllowance,
             );
         });