Merge pull request #760 from 0xProject/refactor/check-revert-reasons

Check Revert Reasons in Contract Tests

16 files changed, 255 insertions, 140 deletions

diff --git a/package.json b/package.json
index 11444d16d..3436f152b 100644
--- a/package.json
+++ b/package.json
@@ -25,6 +25,7 @@
         "build": "wsrun build $PKG --fast-exit -r --stages",
         "build:monorepo_scripts": "PKG=@0xproject/monorepo-scripts yarn build",
         "clean": "wsrun clean $PKG --fast-exit -r --parallel",
+        "remove_node_modules": "lerna clean --yes; rm -rf node_modules",
         "rebuild": "run-s clean build",
         "test": "wsrun test $PKG --fast-exit --serial --exclude-missing",
         "stage_docs": "wsrun docs:stage $PKG --fast-exit --parallel --exclude-missing",
diff --git a/packages/contracts/src/contracts/current/test/Whitelist/Whitelist.sol b/packages/contracts/src/contracts/current/test/Whitelist/Whitelist.sol
index d35815474..8b52858b1 100644
--- a/packages/contracts/src/contracts/current/test/Whitelist/Whitelist.sol
+++ b/packages/contracts/src/contracts/current/test/Whitelist/Whitelist.sol
@@ -23,13 +23,13 @@ import "../../protocol/Exchange/interfaces/IExchange.sol";
 import "../../protocol/Exchange/libs/LibOrder.sol";
 import "../../utils/Ownable/Ownable.sol";
 
-contract Whitelist is 
+contract Whitelist is
     Ownable
 {
     // Revert reasons
-    string constant MAKER_NOT_WHITELISTED = "Maker address not whitelisted.";
-    string constant TAKER_NOT_WHITELISTED = "Taker address not whitelisted.";
-    string constant INVALID_SENDER = "Sender must equal transaction origin.";
+    string constant MAKER_NOT_WHITELISTED = "MAKER_NOT_WHITELISTED"; // Maker address not whitelisted.
+    string constant TAKER_NOT_WHITELISTED = "TAKER_NOT_WHITELISTED"; // Taker address not whitelisted.
+    string constant INVALID_SENDER = "INVALID_SENDER"; // Sender must equal transaction origin.
 
     // Mapping of address => whitelist status.
     mapping (address => bool) public isWhitelisted;
@@ -77,7 +77,7 @@ contract Whitelist is
         public
     {
         address takerAddress = msg.sender;
-    
+
         // This contract must be the entry point for the transaction.
         require(
             takerAddress == tx.origin,
diff --git a/packages/contracts/src/contracts/current/tokens/ERC20Token/ERC20Token.sol b/packages/contracts/src/contracts/current/tokens/ERC20Token/ERC20Token.sol
index f0bcdafef..b6961a6ec 100644
--- a/packages/contracts/src/contracts/current/tokens/ERC20Token/ERC20Token.sol
+++ b/packages/contracts/src/contracts/current/tokens/ERC20Token/ERC20Token.sol
@@ -23,8 +23,8 @@ import "./IERC20Token.sol";
 
 contract ERC20Token is IERC20Token {
 
-    string constant INSUFFICIENT_BALANCE = "Insufficient balance to complete transfer.";
-    string constant INSUFFICIENT_ALLOWANCE = "Insufficient allowance to complete transfer.";
+    string constant INSUFFICIENT_BALANCE = "ERC20_INSUFFICIENT_BALANCE";
+    string constant INSUFFICIENT_ALLOWANCE = "ERC20_INSUFFICIENT_ALLOWANCE";
     string constant OVERFLOW = "Transfer would result in an overflow.";
 
     mapping (address => uint256) balances;
@@ -97,4 +97,3 @@ contract ERC20Token is IERC20Token {
         return allowed[_owner][_spender];
     }
 }
-
diff --git a/packages/contracts/src/utils/assertions.ts b/packages/contracts/src/utils/assertions.ts
index 615e648f3..e702a3200 100644
--- a/packages/contracts/src/utils/assertions.ts
+++ b/packages/contracts/src/utils/assertions.ts
@@ -1,3 +1,4 @@
+import { RevertReason } from '@0xproject/types';
 import * as chai from 'chai';
 import * as _ from 'lodash';
 
@@ -52,6 +53,21 @@ export function expectRevertOrAlwaysFailingTransactionAsync<T>(p: Promise<T>): P
 }
 
 /**
+ * Rejects if the given Promise does not reject with the given revert reason or "always
+ * failing transaction" error.
+ * @param p the Promise which is expected to reject
+ * @param reason a specific revert reason
+ * @returns a new Promise which will reject if the conditions are not met and
+ * otherwise resolve with no value.
+ */
+export function expectRevertReasonOrAlwaysFailingTransactionAsync<T>(
+    p: Promise<T>,
+    reason: RevertReason,
+): PromiseLike<void> {
+    return _expectEitherErrorAsync(p, 'always failing transaction', reason);
+}
+
+/**
  * Rejects if the given Promise does not reject with a "revert" or "Contract
  * call failed" error.
  * @param p the Promise which is expected to reject
diff --git a/packages/contracts/src/utils/constants.ts b/packages/contracts/src/utils/constants.ts
index f21b8c7a0..2b2bd2425 100644
--- a/packages/contracts/src/utils/constants.ts
+++ b/packages/contracts/src/utils/constants.ts
@@ -19,19 +19,6 @@ const TESTRPC_PRIVATE_KEYS_STRINGS = [
 export const constants = {
     INVALID_OPCODE: 'invalid opcode',
     REVERT: 'revert',
-    LIB_BYTES_GREATER_THAN_ZERO_LENGTH_REQUIRED: 'GREATER_THAN_ZERO_LENGTH_REQUIRED',
-    LIB_BYTES_GREATER_OR_EQUAL_TO_4_LENGTH_REQUIRED: 'GREATER_OR_EQUAL_TO_4_LENGTH_REQUIRED',
-    LIB_BYTES_GREATER_OR_EQUAL_TO_20_LENGTH_REQUIRED: 'GREATER_OR_EQUAL_TO_20_LENGTH_REQUIRED',
-    LIB_BYTES_GREATER_OR_EQUAL_TO_32_LENGTH_REQUIRED: 'GREATER_OR_EQUAL_TO_32_LENGTH_REQUIRED',
-    LIB_BYTES_GREATER_OR_EQUAL_TO_NESTED_BYTES_LENGTH_REQUIRED: 'GREATER_OR_EQUAL_TO_NESTED_BYTES_LENGTH_REQUIRED',
-    LIB_BYTES_GREATER_OR_EQUAL_TO_SOURCE_BYTES_LENGTH_REQUIRED: 'GREATER_OR_EQUAL_TO_SOURCE_BYTES_LENGTH_REQUIRED',
-    ERC20_INSUFFICIENT_BALANCE: 'Insufficient balance to complete transfer.',
-    ERC20_INSUFFICIENT_ALLOWANCE: 'Insufficient allowance to complete transfer.',
-    EXCHANGE_LENGTH_GREATER_THAN_0_REQUIRED: 'LENGTH_GREATER_THAN_0_REQUIRED',
-    EXCHANGE_SIGNATURE_UNSUPPORTED: 'SIGNATURE_UNSUPPORTED',
-    EXCHANGE_SIGNATURE_ILLEGAL: 'SIGNATURE_ILLEGAL',
-    EXCHANGE_LENGTH_0_REQUIRED: 'LENGTH_0_REQUIRED',
-    EXCHANGE_LENGTH_65_REQUIRED: 'LENGTH_65_REQUIRED',
     TESTRPC_NETWORK_ID: 50,
     // Note(albrow): In practice V8 and most other engines limit the minimum
     // interval for setInterval to 10ms. We still set it to 0 here in order to
diff --git a/packages/contracts/test/asset_proxy/authorizable.ts b/packages/contracts/test/asset_proxy/authorizable.ts
index c35dc7882..c2295dda6 100644
--- a/packages/contracts/test/asset_proxy/authorizable.ts
+++ b/packages/contracts/test/asset_proxy/authorizable.ts
@@ -1,10 +1,14 @@
 import { BlockchainLifecycle } from '@0xproject/dev-utils';
+import { RevertReason } from '@0xproject/types';
 import { BigNumber } from '@0xproject/utils';
 import * as chai from 'chai';
 
 import { MixinAuthorizableContract } from '../../src/generated_contract_wrappers/mixin_authorizable';
 import { artifacts } from '../../src/utils/artifacts';
-import { expectRevertOrAlwaysFailingTransactionAsync } from '../../src/utils/assertions';
+import {
+    expectRevertOrAlwaysFailingTransactionAsync,
+    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';
@@ -43,8 +47,9 @@ describe('Authorizable', () => {
     });
     describe('addAuthorizedAddress', () => {
         it('should throw if not called by owner', async () => {
-            return expectRevertOrAlwaysFailingTransactionAsync(
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
                 authorizable.addAuthorizedAddress.sendTransactionAsync(notOwner, { from: notOwner }),
+                RevertReason.OnlyContractOwner,
             );
         });
         it('should allow owner to add an authorized address', async () => {
@@ -60,8 +65,9 @@ describe('Authorizable', () => {
                 await authorizable.addAuthorizedAddress.sendTransactionAsync(address, { from: owner }),
                 constants.AWAIT_TRANSACTION_MINED_MS,
             );
-            return expectRevertOrAlwaysFailingTransactionAsync(
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
                 authorizable.addAuthorizedAddress.sendTransactionAsync(address, { from: owner }),
+                RevertReason.TargetAlreadyAuthorized,
             );
         });
     });
@@ -72,10 +78,11 @@ describe('Authorizable', () => {
                 await authorizable.addAuthorizedAddress.sendTransactionAsync(address, { from: owner }),
                 constants.AWAIT_TRANSACTION_MINED_MS,
             );
-            return expectRevertOrAlwaysFailingTransactionAsync(
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
                 authorizable.removeAuthorizedAddress.sendTransactionAsync(address, {
                     from: notOwner,
                 }),
+                RevertReason.OnlyContractOwner,
             );
         });
 
@@ -95,10 +102,11 @@ describe('Authorizable', () => {
         });
 
         it('should throw if owner attempts to remove an address that is not authorized', async () => {
-            return expectRevertOrAlwaysFailingTransactionAsync(
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
                 authorizable.removeAuthorizedAddress.sendTransactionAsync(address, {
                     from: owner,
                 }),
+                RevertReason.TargetNotAuthorized,
             );
         });
     });
diff --git a/packages/contracts/test/asset_proxy/proxies.ts b/packages/contracts/test/asset_proxy/proxies.ts
index 2313c0b0e..7960e46d2 100644
--- a/packages/contracts/test/asset_proxy/proxies.ts
+++ b/packages/contracts/test/asset_proxy/proxies.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 * as chai from 'chai';
 import { LogWithDecodedArgs } from 'ethereum-types';
@@ -15,7 +16,10 @@ 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 {
+    expectRevertOrAlwaysFailingTransactionAsync,
+    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';
@@ -158,14 +162,15 @@ 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,
                 );
             });
 
@@ -175,10 +180,11 @@ describe('Asset Transfer Proxies', () => {
 
                 // Perform a transfer from makerAddress to takerAddress
                 const amount = new BigNumber(10);
-                return expectRevertOrAlwaysFailingTransactionAsync(
+                return expectRevertReasonOrAlwaysFailingTransactionAsync(
                     erc20Proxy.transferFrom.sendTransactionAsync(encodedAssetData, makerAddress, takerAddress, amount, {
                         from: notAuthorized,
                     }),
+                    RevertReason.SenderNotAuthorized,
                 );
             });
         });
@@ -226,10 +232,11 @@ describe('Asset Transfer Proxies', () => {
                 const toAddresses = _.times(numTransfers, () => takerAddress);
                 const amounts = _.times(numTransfers, () => amount);
 
-                return expectRevertOrAlwaysFailingTransactionAsync(
+                return expectRevertReasonOrAlwaysFailingTransactionAsync(
                     erc20Proxy.batchTransferFrom.sendTransactionAsync(assetData, fromAddresses, toAddresses, amounts, {
                         from: notAuthorized,
                     }),
+                    RevertReason.SenderNotAuthorized,
                 );
             });
         });
@@ -363,7 +370,7 @@ describe('Asset Transfer Proxies', () => {
                 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(
                         encodedAssetData,
                         makerAddress,
@@ -371,6 +378,7 @@ describe('Asset Transfer Proxies', () => {
                         amount,
                         { from: exchangeAddress },
                     ),
+                    RevertReason.InvalidAmount,
                 );
             });
 
@@ -382,7 +390,7 @@ describe('Asset Transfer Proxies', () => {
                 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(
                         encodedAssetData,
                         makerAddress,
@@ -390,6 +398,7 @@ describe('Asset Transfer Proxies', () => {
                         amount,
                         { from: exchangeAddress },
                     ),
+                    RevertReason.InvalidAmount,
                 );
             });
 
@@ -405,10 +414,11 @@ describe('Asset Transfer Proxies', () => {
                 );
                 // Perform a transfer; expect this to fail.
                 const amount = new BigNumber(1);
-                return expectRevertOrAlwaysFailingTransactionAsync(
+                return expectRevertReasonOrAlwaysFailingTransactionAsync(
                     erc20Proxy.transferFrom.sendTransactionAsync(encodedAssetData, makerAddress, takerAddress, amount, {
-                        from: notAuthorized,
+                        from: exchangeAddress,
                     }),
+                    RevertReason.TransferFailed,
                 );
             });
 
@@ -417,7 +427,7 @@ describe('Asset Transfer Proxies', () => {
                 const encodedAssetData = assetProxyUtils.encodeERC721AssetData(erc721Token.address, erc721MakerTokenId);
                 // Perform a transfer from makerAddress to takerAddress
                 const amount = new BigNumber(1);
-                return expectRevertOrAlwaysFailingTransactionAsync(
+                return expectRevertReasonOrAlwaysFailingTransactionAsync(
                     erc721Proxy.transferFrom.sendTransactionAsync(
                         encodedAssetData,
                         makerAddress,
@@ -425,6 +435,7 @@ describe('Asset Transfer Proxies', () => {
                         amount,
                         { from: notAuthorized },
                     ),
+                    RevertReason.SenderNotAuthorized,
                 );
             });
         });
@@ -475,10 +486,11 @@ describe('Asset Transfer Proxies', () => {
                 const toAddresses = _.times(numTransfers, () => takerAddress);
                 const amounts = _.times(numTransfers, () => new BigNumber(1));
 
-                return expectRevertOrAlwaysFailingTransactionAsync(
+                return expectRevertReasonOrAlwaysFailingTransactionAsync(
                     erc721Proxy.batchTransferFrom.sendTransactionAsync(assetData, fromAddresses, toAddresses, amounts, {
                         from: notAuthorized,
                     }),
+                    RevertReason.SenderNotAuthorized,
                 );
             });
         });
diff --git a/packages/contracts/test/exchange/core.ts b/packages/contracts/test/exchange/core.ts
index 5b2d4590f..99d2bc157 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 +17,10 @@ import {
     FillContractEventArgs,
 } from '../../src/generated_contract_wrappers/exchange';
 import { artifacts } from '../../src/utils/artifacts';
-import { expectRevertOrAlwaysFailingTransactionAsync } from '../../src/utils/assertions';
+import {
+    expectRevertOrAlwaysFailingTransactionAsync,
+    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';
@@ -415,8 +418,9 @@ 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 +436,9 @@ 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 +447,9 @@ describe('Exchange core', () => {
                 makerAssetAmount: new BigNumber(0),
             });
 
-            return expectRevertOrAlwaysFailingTransactionAsync(
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
                 exchangeWrapper.fillOrderAsync(signedOrder, takerAddress),
+                RevertReason.OrderUnfillable,
             );
         });
 
@@ -452,18 +458,20 @@ 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 +480,9 @@ describe('Exchange core', () => {
                 makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(100000), 18),
             });
 
-            return expectRevertOrAlwaysFailingTransactionAsync(
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
                 exchangeWrapper.fillOrderAsync(signedOrder, takerAddress),
+                RevertReason.TransferFailed,
             );
         });
 
@@ -481,8 +490,9 @@ 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 +503,9 @@ describe('Exchange core', () => {
                 }),
                 constants.AWAIT_TRANSACTION_MINED_MS,
             );
-            return expectRevertOrAlwaysFailingTransactionAsync(
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
                 exchangeWrapper.fillOrderAsync(signedOrder, takerAddress),
+                RevertReason.TransferFailed,
             );
         });
 
@@ -505,8 +516,9 @@ describe('Exchange core', () => {
                 }),
                 constants.AWAIT_TRANSACTION_MINED_MS,
             );
-            return expectRevertOrAlwaysFailingTransactionAsync(
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
                 exchangeWrapper.fillOrderAsync(signedOrder, takerAddress),
+                RevertReason.TransferFailed,
             );
         });
 
@@ -514,16 +526,18 @@ 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 +549,9 @@ describe('Exchange core', () => {
         });
 
         it('should throw if not sent by maker', async () => {
-            return expectRevertOrAlwaysFailingTransactionAsync(
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
                 exchangeWrapper.cancelOrderAsync(signedOrder, takerAddress),
+                RevertReason.InvalidMaker,
             );
         });
 
@@ -545,8 +560,9 @@ describe('Exchange core', () => {
                 makerAssetAmount: new BigNumber(0),
             });
 
-            return expectRevertOrAlwaysFailingTransactionAsync(
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
                 exchangeWrapper.cancelOrderAsync(signedOrder, makerAddress),
+                RevertReason.OrderUnfillable,
             );
         });
 
@@ -555,17 +571,19 @@ 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 +604,9 @@ 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 +614,9 @@ 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 +632,11 @@ describe('Exchange core', () => {
             });
 
             const fillTakerAssetAmount2 = new BigNumber(1);
-            return expectRevertOrAlwaysFailingTransactionAsync(
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
                 exchangeWrapper.fillOrderAsync(signedOrder, takerAddress, {
                     takerAssetFillAmount: fillTakerAssetAmount2,
                 }),
+                RevertReason.RoundingError,
             );
         });
     });
@@ -625,16 +646,18 @@ 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,
             );
         });
 
@@ -792,8 +815,9 @@ 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,
             );
         });
 
@@ -814,30 +838,26 @@ 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,
             );
         });
 
         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.encodeERC721AssetData(erc721Token.address, takerAssetId),
+                takerAssetData: assetProxyUtils.encodeERC20AssetData(defaultTakerAssetAddress),
             });
-            // Verify pre-conditions
-            const initialOwnerMakerAsset = await erc721Token.ownerOf.callAsync(makerAssetId);
-            expect(initialOwnerMakerAsset).to.be.bignumber.equal(makerAddress);
-            const initialOwnerTakerAsset = await erc721Token.ownerOf.callAsync(takerAssetId);
-            expect(initialOwnerTakerAsset).to.be.bignumber.equal(takerAddress);
             // Call Exchange
-            const takerAssetFillAmount = signedOrder.takerAssetAmount;
-            return expectRevertOrAlwaysFailingTransactionAsync(
+            const takerAssetFillAmount = signedOrder.takerAssetAmount.div(2);
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
                 exchangeWrapper.fillOrderAsync(signedOrder, takerAddress, { takerAssetFillAmount }),
+                RevertReason.RoundingError,
             );
         });
 
diff --git a/packages/contracts/test/exchange/dispatcher.ts b/packages/contracts/test/exchange/dispatcher.ts
index f96f15f16..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,
             );
         });
     });
@@ -305,7 +308,7 @@ describe('AssetProxyDispatcher', () => {
             const encodedAssetData = assetProxyUtils.encodeERC20AssetData(zrxToken.address);
             // Perform a transfer from makerAddress to takerAddress
             const amount = new BigNumber(10);
-            return expectRevertOrAlwaysFailingTransactionAsync(
+            return expectRevertReasonOrAlwaysFailingTransactionAsync(
                 assetProxyDispatcher.publicDispatchTransferFrom.sendTransactionAsync(
                     encodedAssetData,
                     makerAddress,
@@ -313,6 +316,7 @@ describe('AssetProxyDispatcher', () => {
                     amount,
                     { from: owner },
                 ),
+                RevertReason.AssetProxyDoesNotExist,
             );
         });
     });
diff --git a/packages/contracts/test/exchange/match_orders.ts b/packages/contracts/test/exchange/match_orders.ts
index 18a46187f..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';
@@ -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 43b9f46b2..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);
@@ -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 a39a81057..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';
@@ -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 56f1dc2bc..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';
@@ -101,7 +102,7 @@ describe('LibBytes', () => {
         it('should revert if length is 0', async () => {
             return expectRevertOrOtherErrorAsync(
                 libBytes.publicPopLastByte.callAsync(constants.NULL_BYTES),
-                constants.LIB_BYTES_GREATER_THAN_ZERO_LENGTH_REQUIRED,
+                RevertReason.LibBytesGreaterThanZeroLengthRequired,
             );
         });
         it('should pop the last byte from the input and return it', async () => {
@@ -117,7 +118,7 @@ describe('LibBytes', () => {
         it('should revert if length is less than 20', async () => {
             return expectRevertOrOtherErrorAsync(
                 libBytes.publicPopLast20Bytes.callAsync(byteArrayShorterThan20Bytes),
-                constants.LIB_BYTES_GREATER_OR_EQUAL_TO_20_LENGTH_REQUIRED,
+                RevertReason.LibBytesGreaterOrEqualTo20LengthRequired,
             );
         });
         it('should pop the last 20 bytes from the input and return it', async () => {
@@ -185,7 +186,7 @@ describe('LibBytes', () => {
         it('should revert if dest is shorter than source', async () => {
             return expectRevertOrOtherErrorAsync(
                 libBytes.publicDeepCopyBytes.callAsync(byteArrayShorterThan32Bytes, byteArrayLongerThan32Bytes),
-                constants.LIB_BYTES_GREATER_OR_EQUAL_TO_SOURCE_BYTES_LENGTH_REQUIRED,
+                RevertReason.LibBytesGreaterOrEqualToSourceBytesLengthRequired,
             );
         });
         it('should overwrite dest with source if source and dest have equal length', async () => {
@@ -238,7 +239,7 @@ describe('LibBytes', () => {
             const offset = new BigNumber(0);
             return expectRevertOrOtherErrorAsync(
                 libBytes.publicReadAddress.callAsync(shortByteArray, offset),
-                constants.LIB_BYTES_GREATER_OR_EQUAL_TO_20_LENGTH_REQUIRED,
+                RevertReason.LibBytesGreaterOrEqualTo20LengthRequired,
             );
         });
         it('should fail if the length between the offset and end of the byte array is too short to hold an address', async () => {
@@ -246,7 +247,7 @@ describe('LibBytes', () => {
             const badOffset = new BigNumber(ethUtil.toBuffer(byteArray).byteLength);
             return expectRevertOrOtherErrorAsync(
                 libBytes.publicReadAddress.callAsync(byteArray, badOffset),
-                constants.LIB_BYTES_GREATER_OR_EQUAL_TO_20_LENGTH_REQUIRED,
+                RevertReason.LibBytesGreaterOrEqualTo20LengthRequired,
             );
         });
     });
@@ -282,7 +283,7 @@ describe('LibBytes', () => {
             const offset = new BigNumber(0);
             return expectRevertOrOtherErrorAsync(
                 libBytes.publicWriteAddress.callAsync(byteArrayShorterThan20Bytes, offset, testAddress),
-                constants.LIB_BYTES_GREATER_OR_EQUAL_TO_20_LENGTH_REQUIRED,
+                RevertReason.LibBytesGreaterOrEqualTo20LengthRequired,
             );
         });
         it('should fail if the length between the offset and end of the byte array is too short to hold an address', async () => {
@@ -290,7 +291,7 @@ describe('LibBytes', () => {
             const badOffset = new BigNumber(ethUtil.toBuffer(byteArray).byteLength);
             return expectRevertOrOtherErrorAsync(
                 libBytes.publicWriteAddress.callAsync(byteArray, badOffset, testAddress),
-                constants.LIB_BYTES_GREATER_OR_EQUAL_TO_20_LENGTH_REQUIRED,
+                RevertReason.LibBytesGreaterOrEqualTo20LengthRequired,
             );
         });
     });
@@ -314,14 +315,14 @@ describe('LibBytes', () => {
             const offset = new BigNumber(0);
             return expectRevertOrOtherErrorAsync(
                 libBytes.publicReadBytes32.callAsync(byteArrayShorterThan32Bytes, offset),
-                constants.LIB_BYTES_GREATER_OR_EQUAL_TO_32_LENGTH_REQUIRED,
+                RevertReason.LibBytesGreaterOrEqualTo32LengthRequired,
             );
         });
         it('should fail if the length between the offset and end of the byte array is too short to hold a bytes32', async () => {
             const badOffset = new BigNumber(ethUtil.toBuffer(testBytes32).byteLength);
             return expectRevertOrOtherErrorAsync(
                 libBytes.publicReadBytes32.callAsync(testBytes32, badOffset),
-                constants.LIB_BYTES_GREATER_OR_EQUAL_TO_32_LENGTH_REQUIRED,
+                RevertReason.LibBytesGreaterOrEqualTo32LengthRequired,
             );
         });
     });
@@ -357,7 +358,7 @@ describe('LibBytes', () => {
             const offset = new BigNumber(0);
             return expectRevertOrOtherErrorAsync(
                 libBytes.publicWriteBytes32.callAsync(byteArrayShorterThan32Bytes, offset, testBytes32),
-                constants.LIB_BYTES_GREATER_OR_EQUAL_TO_32_LENGTH_REQUIRED,
+                RevertReason.LibBytesGreaterOrEqualTo32LengthRequired,
             );
         });
         it('should fail if the length between the offset and end of the byte array is too short to hold a bytes32', async () => {
@@ -365,7 +366,7 @@ describe('LibBytes', () => {
             const badOffset = new BigNumber(ethUtil.toBuffer(byteArray).byteLength);
             return expectRevertOrOtherErrorAsync(
                 libBytes.publicWriteBytes32.callAsync(byteArray, badOffset, testBytes32),
-                constants.LIB_BYTES_GREATER_OR_EQUAL_TO_32_LENGTH_REQUIRED,
+                RevertReason.LibBytesGreaterOrEqualTo32LengthRequired,
             );
         });
     });
@@ -393,7 +394,7 @@ describe('LibBytes', () => {
             const offset = new BigNumber(0);
             return expectRevertOrOtherErrorAsync(
                 libBytes.publicReadUint256.callAsync(byteArrayShorterThan32Bytes, offset),
-                constants.LIB_BYTES_GREATER_OR_EQUAL_TO_32_LENGTH_REQUIRED,
+                RevertReason.LibBytesGreaterOrEqualTo32LengthRequired,
             );
         });
         it('should fail if the length between the offset and end of the byte array is too short to hold a uint256', async () => {
@@ -403,7 +404,7 @@ describe('LibBytes', () => {
             const badOffset = new BigNumber(testUint256AsBuffer.byteLength);
             return expectRevertOrOtherErrorAsync(
                 libBytes.publicReadUint256.callAsync(byteArray, badOffset),
-                constants.LIB_BYTES_GREATER_OR_EQUAL_TO_32_LENGTH_REQUIRED,
+                RevertReason.LibBytesGreaterOrEqualTo32LengthRequired,
             );
         });
     });
@@ -443,7 +444,7 @@ describe('LibBytes', () => {
             const offset = new BigNumber(0);
             return expectRevertOrOtherErrorAsync(
                 libBytes.publicWriteUint256.callAsync(byteArrayShorterThan32Bytes, offset, testUint256),
-                constants.LIB_BYTES_GREATER_OR_EQUAL_TO_32_LENGTH_REQUIRED,
+                RevertReason.LibBytesGreaterOrEqualTo32LengthRequired,
             );
         });
         it('should fail if the length between the offset and end of the byte array is too short to hold a uint256', async () => {
@@ -451,7 +452,7 @@ describe('LibBytes', () => {
             const badOffset = new BigNumber(ethUtil.toBuffer(byteArray).byteLength);
             return expectRevertOrOtherErrorAsync(
                 libBytes.publicWriteUint256.callAsync(byteArray, badOffset, testUint256),
-                constants.LIB_BYTES_GREATER_OR_EQUAL_TO_32_LENGTH_REQUIRED,
+                RevertReason.LibBytesGreaterOrEqualTo32LengthRequired,
             );
         });
     });
@@ -462,7 +463,7 @@ describe('LibBytes', () => {
             const byteArrayLessThan4Bytes = '0x010101';
             return expectRevertOrOtherErrorAsync(
                 libBytes.publicReadBytes4.callAsync(byteArrayLessThan4Bytes, new BigNumber(0)),
-                constants.LIB_BYTES_GREATER_OR_EQUAL_TO_4_LENGTH_REQUIRED,
+                RevertReason.LibBytesGreaterOrEqualTo4LengthRequired,
             );
         });
         it('should return the first 4 bytes of a byte array of arbitrary length', async () => {
@@ -517,28 +518,28 @@ describe('LibBytes', () => {
             const offset = new BigNumber(0);
             return expectRevertOrOtherErrorAsync(
                 libBytes.publicReadBytesWithLength.callAsync(byteArrayShorterThan32Bytes, offset),
-                constants.LIB_BYTES_GREATER_OR_EQUAL_TO_32_LENGTH_REQUIRED,
+                RevertReason.LibBytesGreaterOrEqualTo32LengthRequired,
             );
         });
         it('should fail if we store a nested byte array length, without a nested byte array', async () => {
             const offset = new BigNumber(0);
             return expectRevertOrOtherErrorAsync(
                 libBytes.publicReadBytesWithLength.callAsync(testBytes32, offset),
-                constants.LIB_BYTES_GREATER_OR_EQUAL_TO_NESTED_BYTES_LENGTH_REQUIRED,
+                RevertReason.LibBytesGreaterOrEqualToNestedBytesLengthRequired,
             );
         });
         it('should fail if the length between the offset and end of the byte array is too short to hold the length of a nested byte array', async () => {
             const badOffset = new BigNumber(ethUtil.toBuffer(byteArrayShorterThan32Bytes).byteLength);
             return expectRevertOrOtherErrorAsync(
                 libBytes.publicReadBytesWithLength.callAsync(byteArrayShorterThan32Bytes, badOffset),
-                constants.LIB_BYTES_GREATER_OR_EQUAL_TO_32_LENGTH_REQUIRED,
+                RevertReason.LibBytesGreaterOrEqualTo32LengthRequired,
             );
         });
         it('should fail if the length between the offset and end of the byte array is too short to hold the nested byte array', async () => {
             const badOffset = new BigNumber(ethUtil.toBuffer(testBytes32).byteLength);
             return expectRevertOrOtherErrorAsync(
                 libBytes.publicReadBytesWithLength.callAsync(testBytes32, badOffset),
-                constants.LIB_BYTES_GREATER_OR_EQUAL_TO_32_LENGTH_REQUIRED,
+                RevertReason.LibBytesGreaterOrEqualTo32LengthRequired,
             );
         });
     });
@@ -650,7 +651,7 @@ describe('LibBytes', () => {
             const emptyByteArray = ethUtil.bufferToHex(new Buffer(1));
             return expectRevertOrOtherErrorAsync(
                 libBytes.publicWriteBytesWithLength.callAsync(emptyByteArray, offset, longData),
-                constants.LIB_BYTES_GREATER_OR_EQUAL_TO_NESTED_BYTES_LENGTH_REQUIRED,
+                RevertReason.LibBytesGreaterOrEqualToNestedBytesLengthRequired,
             );
         });
         it('should fail if the length between the offset and end of the byte array is too short to hold the length of a nested byte array)', async () => {
@@ -658,7 +659,7 @@ describe('LibBytes', () => {
             const badOffset = new BigNumber(ethUtil.toBuffer(shortTestBytesAsBuffer).byteLength);
             return expectRevertOrOtherErrorAsync(
                 libBytes.publicWriteBytesWithLength.callAsync(emptyByteArray, badOffset, shortData),
-                constants.LIB_BYTES_GREATER_OR_EQUAL_TO_NESTED_BYTES_LENGTH_REQUIRED,
+                RevertReason.LibBytesGreaterOrEqualToNestedBytesLengthRequired,
             );
         });
     });
diff --git a/packages/contracts/test/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,
             );
         });
 
diff --git a/packages/types/src/index.ts b/packages/types/src/index.ts
index 88abdc1e7..423292d45 100644
--- a/packages/types/src/index.ts
+++ b/packages/types/src/index.ts
@@ -168,3 +168,47 @@ export interface ERC721AssetData {
     tokenId: BigNumber;
     receiverData: string;
 }
+
+export enum RevertReason {
+    OrderUnfillable = 'ORDER_UNFILLABLE',
+    InvalidMaker = 'INVALID_MAKER',
+    InvalidTaker = 'INVALID_TAKER',
+    InvalidSender = 'INVALID_SENDER',
+    InvalidOrderSignature = 'INVALID_ORDER_SIGNATURE',
+    InvalidTakerAmount = 'INVALID_TAKER_AMOUNT',
+    RoundingError = 'ROUNDING_ERROR',
+    InvalidSignature = 'INVALID_SIGNATURE',
+    SignatureIllegal = 'SIGNATURE_ILLEGAL',
+    SignatureUnsupported = 'SIGNATURE_UNSUPPORTED',
+    InvalidNewOrderEpoch = 'INVALID_NEW_ORDER_EPOCH',
+    CompleteFillFailed = 'COMPLETE_FILL_FAILED',
+    NegativeSpreadRequired = 'NEGATIVE_SPREAD_REQUIRED',
+    ReentrancyIllegal = 'REENTRANCY_ILLEGAL',
+    InvalidTxHash = 'INVALID_TX_HASH',
+    InvalidTxSignature = 'INVALID_TX_SIGNATURE',
+    FailedExecution = 'FAILED_EXECUTION',
+    AssetProxyMismatch = 'ASSET_PROXY_MISMATCH',
+    AssetProxyIdMismatch = 'ASSET_PROXY_ID_MISMATCH',
+    LengthGreaterThan0Required = 'LENGTH_GREATER_THAN_0_REQUIRED',
+    Length0Required = 'LENGTH_0_REQUIRED',
+    Length65Required = 'LENGTH_65_REQUIRED',
+    InvalidAmount = 'INVALID_AMOUNT',
+    TransferFailed = 'TRANSFER_FAILED',
+    SenderNotAuthorized = 'SENDER_NOT_AUTHORIZED',
+    TargetNotAuthorized = 'TARGET_NOT_AUTHORIZED',
+    TargetAlreadyAuthorized = 'TARGET_ALREADY_AUTHORIZED',
+    IndexOutOfBounds = 'INDEX_OUT_OF_BOUNDS',
+    AuthorizedAddressMismatch = 'AUTHORIZED_ADDRESS_MISMATCH',
+    OnlyContractOwner = 'ONLY_CONTRACT_OWNER',
+    MakerNotWhitelisted = 'MAKER_NOT_WHITELISTED',
+    TakerNotWhitelisted = 'TAKER_NOT_WHITELISTED',
+    AssetProxyDoesNotExist = 'ASSET_PROXY_DOES_NOT_EXIST',
+    LibBytesGreaterThanZeroLengthRequired = 'GREATER_THAN_ZERO_LENGTH_REQUIRED',
+    LibBytesGreaterOrEqualTo4LengthRequired = 'GREATER_OR_EQUAL_TO_4_LENGTH_REQUIRED',
+    LibBytesGreaterOrEqualTo20LengthRequired = 'GREATER_OR_EQUAL_TO_20_LENGTH_REQUIRED',
+    LibBytesGreaterOrEqualTo32LengthRequired = 'GREATER_OR_EQUAL_TO_32_LENGTH_REQUIRED',
+    LibBytesGreaterOrEqualToNestedBytesLengthRequired = 'GREATER_OR_EQUAL_TO_NESTED_BYTES_LENGTH_REQUIRED',
+    LibBytesGreaterOrEqualToSourceBytesLengthRequired = 'GREATER_OR_EQUAL_TO_SOURCE_BYTES_LENGTH_REQUIRED',
+    Erc20InsufficientBalance = 'ERC20_INSUFFICIENT_BALANCE',
+    Erc20InsufficientAllowance = 'ERC20_INSUFFICIENT_ALLOWANCE',
+}