Merge branch 'development'

* development: (939 commits)
  Add asset-buyer to published packages section in README
  Publish
  Updated CHANGELOGS
  Update BuyQuote interface
  force re-build
  Add website build to instructions
  Revert format and re-add changes
  Build website in parallel with other tests since no other test relies on it being built to run
  Add back sourceMap support for both dev/prod
  Upgrade webpack
  Add missing default options
  Remove unused constants
  Add fee order with a takerFee
  Add additional order factory methods and refactor test to use them
  Add comments about buy quote calculation
  Update CHANGELOG
  Fix linter
  Add additional test for slippage
  Add buy_quote_calculator_test
  Add 0x Instant to bundle analysis
  ...

19 files changed, 550 insertions, 195 deletions

diff --git a/packages/contracts/test/utils/address_utils.ts b/packages/contracts/test/utils/address_utils.ts
index a9fb6921a..3cf8ec786 100644
--- a/packages/contracts/test/utils/address_utils.ts
+++ b/packages/contracts/test/utils/address_utils.ts
@@ -1,4 +1,5 @@
-import { crypto, generatePseudoRandomSalt } from '@0xproject/order-utils';
+import { generatePseudoRandomSalt } from '@0xproject/order-utils';
+import { crypto } from '@0xproject/order-utils/lib/src/crypto';
 
 export const addressUtils = {
     generatePseudoRandomAddress(): string {
diff --git a/packages/contracts/test/utils/artifacts.ts b/packages/contracts/test/utils/artifacts.ts
index e608ee174..53f2a4e4e 100644
--- a/packages/contracts/test/utils/artifacts.ts
+++ b/packages/contracts/test/utils/artifacts.ts
@@ -1,18 +1,23 @@
-import { ContractArtifact } from '@0xproject/sol-compiler';
+import { ContractArtifact } from 'ethereum-types';
 
 import * as AssetProxyOwner from '../../artifacts/AssetProxyOwner.json';
 import * as DummyERC20Token from '../../artifacts/DummyERC20Token.json';
 import * as DummyERC721Receiver from '../../artifacts/DummyERC721Receiver.json';
 import * as DummyERC721Token from '../../artifacts/DummyERC721Token.json';
+import * as DummyMultipleReturnERC20Token from '../../artifacts/DummyMultipleReturnERC20Token.json';
+import * as DummyNoReturnERC20Token from '../../artifacts/DummyNoReturnERC20Token.json';
 import * as ERC20Proxy from '../../artifacts/ERC20Proxy.json';
 import * as ERC721Proxy from '../../artifacts/ERC721Proxy.json';
 import * as Exchange from '../../artifacts/Exchange.json';
 import * as ExchangeWrapper from '../../artifacts/ExchangeWrapper.json';
 import * as Forwarder from '../../artifacts/Forwarder.json';
 import * as IAssetProxy from '../../artifacts/IAssetProxy.json';
+import * as InvalidERC721Receiver from '../../artifacts/InvalidERC721Receiver.json';
 import * as MixinAuthorizable from '../../artifacts/MixinAuthorizable.json';
 import * as MultiSigWallet from '../../artifacts/MultiSigWallet.json';
 import * as MultiSigWalletWithTimeLock from '../../artifacts/MultiSigWalletWithTimeLock.json';
+import * as OrderValidator from '../../artifacts/OrderValidator.json';
+import * as ReentrantERC20Token from '../../artifacts/ReentrantERC20Token.json';
 import * as TestAssetProxyDispatcher from '../../artifacts/TestAssetProxyDispatcher.json';
 import * as TestAssetProxyOwner from '../../artifacts/TestAssetProxyOwner.json';
 import * as TestConstants from '../../artifacts/TestConstants.json';
@@ -20,6 +25,7 @@ import * as TestExchangeInternals from '../../artifacts/TestExchangeInternals.js
 import * as TestLibBytes from '../../artifacts/TestLibBytes.json';
 import * as TestLibs from '../../artifacts/TestLibs.json';
 import * as TestSignatureValidator from '../../artifacts/TestSignatureValidator.json';
+import * as TestStaticCallReceiver from '../../artifacts/TestStaticCallReceiver.json';
 import * as TokenRegistry from '../../artifacts/TokenRegistry.json';
 import * as Validator from '../../artifacts/Validator.json';
 import * as Wallet from '../../artifacts/Wallet.json';
@@ -32,6 +38,8 @@ export const artifacts = {
     DummyERC20Token: (DummyERC20Token as any) as ContractArtifact,
     DummyERC721Receiver: (DummyERC721Receiver as any) as ContractArtifact,
     DummyERC721Token: (DummyERC721Token as any) as ContractArtifact,
+    DummyMultipleReturnERC20Token: (DummyMultipleReturnERC20Token as any) as ContractArtifact,
+    DummyNoReturnERC20Token: (DummyNoReturnERC20Token as any) as ContractArtifact,
     ERC20Proxy: (ERC20Proxy as any) as ContractArtifact,
     ERC721Proxy: (ERC721Proxy as any) as ContractArtifact,
     Exchange: (Exchange as any) as ContractArtifact,
@@ -39,9 +47,12 @@ export const artifacts = {
     EtherToken: (EtherToken as any) as ContractArtifact,
     Forwarder: (Forwarder as any) as ContractArtifact,
     IAssetProxy: (IAssetProxy as any) as ContractArtifact,
+    InvalidERC721Receiver: (InvalidERC721Receiver as any) as ContractArtifact,
     MixinAuthorizable: (MixinAuthorizable as any) as ContractArtifact,
     MultiSigWallet: (MultiSigWallet as any) as ContractArtifact,
     MultiSigWalletWithTimeLock: (MultiSigWalletWithTimeLock as any) as ContractArtifact,
+    OrderValidator: (OrderValidator as any) as ContractArtifact,
+    ReentrantERC20Token: (ReentrantERC20Token as any) as ContractArtifact,
     TestAssetProxyOwner: (TestAssetProxyOwner as any) as ContractArtifact,
     TestAssetProxyDispatcher: (TestAssetProxyDispatcher as any) as ContractArtifact,
     TestConstants: (TestConstants as any) as ContractArtifact,
@@ -49,6 +60,7 @@ export const artifacts = {
     TestLibs: (TestLibs as any) as ContractArtifact,
     TestExchangeInternals: (TestExchangeInternals as any) as ContractArtifact,
     TestSignatureValidator: (TestSignatureValidator as any) as ContractArtifact,
+    TestStaticCallReceiver: (TestStaticCallReceiver as any) as ContractArtifact,
     Validator: (Validator as any) as ContractArtifact,
     Wallet: (Wallet as any) as ContractArtifact,
     TokenRegistry: (TokenRegistry as any) as ContractArtifact,
diff --git a/packages/contracts/test/utils/assertions.ts b/packages/contracts/test/utils/assertions.ts
index 61df800c8..3361a751a 100644
--- a/packages/contracts/test/utils/assertions.ts
+++ b/packages/contracts/test/utils/assertions.ts
@@ -159,7 +159,7 @@ export async function expectTransactionFailedWithoutReasonAsync(p: sendTransacti
  * @returns a new Promise which will reject if the conditions are not met and
  * otherwise resolve with no value.
  */
-export async function expectContractCallFailed<T>(p: Promise<T>, reason: RevertReason): Promise<void> {
+export async function expectContractCallFailedAsync<T>(p: Promise<T>, reason: RevertReason): Promise<void> {
     return expect(p).to.be.rejectedWith(reason);
 }
 
@@ -180,7 +180,20 @@ export async function expectContractCallFailedWithoutReasonAsync<T>(p: Promise<T
  * @returns a new Promise which will reject if the conditions are not met and
  * otherwise resolve with no value.
  */
-export async function expectContractCreationFailedWithoutReason<T>(p: Promise<T>): Promise<void> {
+export async function expectContractCreationFailedAsync<T>(
+    p: sendTransactionResult,
+    reason: RevertReason,
+): Promise<void> {
+    return expectTransactionFailedAsync(p, reason);
+}
+
+/**
+ * Resolves if the contract creation/deployment fails without a revert reason.
+ * @param p a Promise resulting from a contract creation/deployment
+ * @returns a new Promise which will reject if the conditions are not met and
+ * otherwise resolve with no value.
+ */
+export async function expectContractCreationFailedWithoutReasonAsync<T>(p: Promise<T>): Promise<void> {
     const errMessage = await _getTransactionFailedErrorMessageAsync();
     return expect(p).to.be.rejectedWith(errMessage);
 }
diff --git a/packages/contracts/test/utils/block_timestamp.ts b/packages/contracts/test/utils/block_timestamp.ts
index 1159792c4..66c13eed1 100644
--- a/packages/contracts/test/utils/block_timestamp.ts
+++ b/packages/contracts/test/utils/block_timestamp.ts
@@ -35,6 +35,9 @@ export async function increaseTimeAndMineBlockAsync(seconds: number): Promise<nu
  * @returns a new Promise which will resolve with the timestamp in seconds.
  */
 export async function getLatestBlockTimestampAsync(): Promise<number> {
-    const currentBlock = await web3Wrapper.getBlockAsync('latest');
-    return currentBlock.timestamp;
+    const currentBlockIfExists = await web3Wrapper.getBlockIfExistsAsync('latest');
+    if (_.isUndefined(currentBlockIfExists)) {
+        throw new Error(`Unable to fetch latest block.`);
+    }
+    return currentBlockIfExists.timestamp;
 }
diff --git a/packages/contracts/test/utils/constants.ts b/packages/contracts/test/utils/constants.ts
index 65eaee398..b9ba8ccb9 100644
--- a/packages/contracts/test/utils/constants.ts
+++ b/packages/contracts/test/utils/constants.ts
@@ -51,4 +51,17 @@ export const constants = {
     WORD_LENGTH: 32,
     ZERO_AMOUNT: new BigNumber(0),
     PERCENTAGE_DENOMINATOR: new BigNumber(10).pow(18),
+    FUNCTIONS_WITH_MUTEX: [
+        'FILL_ORDER',
+        'FILL_OR_KILL_ORDER',
+        'BATCH_FILL_ORDERS',
+        'BATCH_FILL_OR_KILL_ORDERS',
+        'MARKET_BUY_ORDERS',
+        'MARKET_SELL_ORDERS',
+        'MATCH_ORDERS',
+        'CANCEL_ORDER',
+        'BATCH_CANCEL_ORDERS',
+        'CANCEL_ORDERS_UP_TO',
+        'SET_SIGNATURE_VALIDATOR_APPROVAL',
+    ],
 };
diff --git a/packages/contracts/test/utils/erc20_wrapper.ts b/packages/contracts/test/utils/erc20_wrapper.ts
index 424aae579..526ffe9f8 100644
--- a/packages/contracts/test/utils/erc20_wrapper.ts
+++ b/packages/contracts/test/utils/erc20_wrapper.ts
@@ -20,6 +20,13 @@ export class ERC20Wrapper {
     private readonly _dummyTokenContracts: DummyERC20TokenContract[];
     private _proxyContract?: ERC20ProxyContract;
     private _proxyIdIfExists?: string;
+    /**
+     * Instanitates an ERC20Wrapper
+     * @param provider Web3 provider to use for all JSON RPC requests
+     * @param tokenOwnerAddresses Addresses that we want to endow as owners for dummy ERC20 tokens
+     * @param contractOwnerAddress Desired owner of the contract
+     * Instance of ERC20Wrapper
+     */
     constructor(provider: Provider, tokenOwnerAddresses: string[], contractOwnerAddress: string) {
         this._dummyTokenContracts = [];
         this._web3Wrapper = new Web3Wrapper(provider);
diff --git a/packages/contracts/test/utils/erc721_wrapper.ts b/packages/contracts/test/utils/erc721_wrapper.ts
index d023b4d02..743d10706 100644
--- a/packages/contracts/test/utils/erc721_wrapper.ts
+++ b/packages/contracts/test/utils/erc721_wrapper.ts
@@ -81,7 +81,8 @@ export class ERC721Wrapper {
     }
     public async doesTokenExistAsync(tokenAddress: string, tokenId: BigNumber): Promise<boolean> {
         const tokenContract = this._getTokenContractFromAssetData(tokenAddress);
-        const doesExist = await tokenContract.exists.callAsync(tokenId);
+        const owner = await tokenContract.ownerOf.callAsync(tokenId);
+        const doesExist = owner !== constants.NULL_ADDRESS;
         return doesExist;
     }
     public async approveProxyAsync(tokenAddress: string, tokenId: BigNumber): Promise<void> {
diff --git a/packages/contracts/test/utils/exchange_wrapper.ts b/packages/contracts/test/utils/exchange_wrapper.ts
index d57592d6d..619d43994 100644
--- a/packages/contracts/test/utils/exchange_wrapper.ts
+++ b/packages/contracts/test/utils/exchange_wrapper.ts
@@ -17,7 +17,7 @@ export class ExchangeWrapper {
     constructor(exchangeContract: ExchangeContract, provider: Provider) {
         this._exchange = exchangeContract;
         this._web3Wrapper = new Web3Wrapper(provider);
-        this._logDecoder = new LogDecoder(this._web3Wrapper, this._exchange.address);
+        this._logDecoder = new LogDecoder(this._web3Wrapper);
     }
     public async fillOrderAsync(
         signedOrder: SignedOrder,
@@ -266,4 +266,7 @@ export class ExchangeWrapper {
         );
         return data;
     }
+    public getExchangeAddress(): string {
+        return this._exchange.address;
+    }
 }
diff --git a/packages/contracts/test/utils/fill_order_combinatorial_utils.ts b/packages/contracts/test/utils/fill_order_combinatorial_utils.ts
index 284c4a2db..92d0f4003 100644
--- a/packages/contracts/test/utils/fill_order_combinatorial_utils.ts
+++ b/packages/contracts/test/utils/fill_order_combinatorial_utils.ts
@@ -81,6 +81,12 @@ export async function fillOrderCombinatorialUtilsFactoryAsync(
         erc20FiveDecimalTokenCount,
         fiveDecimals,
     );
+    const zeroDecimals = new BigNumber(0);
+    const erc20ZeroDecimalTokenCount = 2;
+    const [erc20ZeroDecimalTokenA, erc20ZeroDecimalTokenB] = await erc20Wrapper.deployDummyTokensAsync(
+        erc20ZeroDecimalTokenCount,
+        zeroDecimals,
+    );
     const erc20Proxy = await erc20Wrapper.deployProxyAsync();
     await erc20Wrapper.setBalancesAndAllowancesAsync();
 
@@ -119,6 +125,7 @@ export async function fillOrderCombinatorialUtilsFactoryAsync(
         zrxToken.address,
         [erc20EighteenDecimalTokenA.address, erc20EighteenDecimalTokenB.address],
         [erc20FiveDecimalTokenA.address, erc20FiveDecimalTokenB.address],
+        [erc20ZeroDecimalTokenA.address, erc20ZeroDecimalTokenB.address],
         erc721Token,
         erc721Balances,
         exchangeContract.address,
@@ -460,17 +467,17 @@ export class FillOrderCombinatorialUtils {
             ? remainingTakerAmountToFill
             : alreadyFilledTakerAmount.add(takerAssetFillAmount);
 
-        const expFilledMakerAmount = orderUtils.getPartialAmount(
+        const expFilledMakerAmount = orderUtils.getPartialAmountFloor(
             expFilledTakerAmount,
             signedOrder.takerAssetAmount,
             signedOrder.makerAssetAmount,
         );
-        const expMakerFeePaid = orderUtils.getPartialAmount(
+        const expMakerFeePaid = orderUtils.getPartialAmountFloor(
             expFilledTakerAmount,
             signedOrder.takerAssetAmount,
             signedOrder.makerFee,
         );
-        const expTakerFeePaid = orderUtils.getPartialAmount(
+        const expTakerFeePaid = orderUtils.getPartialAmountFloor(
             expFilledTakerAmount,
             signedOrder.takerAssetAmount,
             signedOrder.takerFee,
@@ -497,7 +504,11 @@ export class FillOrderCombinatorialUtils {
         const actFilledTakerAmount = await this.exchangeWrapper.getTakerAssetFilledAmountAsync(orderHash);
         expect(actFilledTakerAmount).to.be.bignumber.equal(expFilledTakerAmount, 'filledTakerAmount');
 
-        expect(txReceipt.logs.length).to.be.equal(1, 'logs length');
+        const exchangeLogs = _.filter(
+            txReceipt.logs,
+            txLog => txLog.address === this.exchangeWrapper.getExchangeAddress(),
+        );
+        expect(exchangeLogs.length).to.be.equal(1, 'logs length');
         // tslint:disable-next-line:no-unnecessary-type-assertion
         const log = txReceipt.logs[0] as LogWithDecodedArgs<ExchangeFillEventArgs>;
         expect(log.args.makerAddress).to.be.equal(makerAddress, 'log.args.makerAddress');
@@ -657,7 +668,7 @@ export class FillOrderCombinatorialUtils {
         signedOrder: SignedOrder,
         takerAssetFillAmount: BigNumber,
     ): Promise<void> {
-        const makerAssetFillAmount = orderUtils.getPartialAmount(
+        const makerAssetFillAmount = orderUtils.getPartialAmountFloor(
             takerAssetFillAmount,
             signedOrder.takerAssetAmount,
             signedOrder.makerAssetAmount,
@@ -694,7 +705,7 @@ export class FillOrderCombinatorialUtils {
                 );
         }
 
-        const makerFee = orderUtils.getPartialAmount(
+        const makerFee = orderUtils.getPartialAmountFloor(
             takerAssetFillAmount,
             signedOrder.takerAssetAmount,
             signedOrder.makerFee,
@@ -818,7 +829,7 @@ export class FillOrderCombinatorialUtils {
                 );
         }
 
-        const takerFee = orderUtils.getPartialAmount(
+        const takerFee = orderUtils.getPartialAmountFloor(
             takerAssetFillAmount,
             signedOrder.takerAssetAmount,
             signedOrder.takerFee,
diff --git a/packages/contracts/test/utils/forwarder_wrapper.ts b/packages/contracts/test/utils/forwarder_wrapper.ts
index 5b9a63ddf..de247a878 100644
--- a/packages/contracts/test/utils/forwarder_wrapper.ts
+++ b/packages/contracts/test/utils/forwarder_wrapper.ts
@@ -58,7 +58,7 @@ export class ForwarderWrapper {
     constructor(contractInstance: ForwarderContract, provider: Provider) {
         this._forwarderContract = contractInstance;
         this._web3Wrapper = new Web3Wrapper(provider);
-        this._logDecoder = new LogDecoder(this._web3Wrapper, this._forwarderContract.address);
+        this._logDecoder = new LogDecoder(this._web3Wrapper);
     }
     public async marketSellOrdersWithEthAsync(
         orders: SignedOrder[],
diff --git a/packages/contracts/test/utils/log_decoder.ts b/packages/contracts/test/utils/log_decoder.ts
index 5a4801319..144a18dd1 100644
--- a/packages/contracts/test/utils/log_decoder.ts
+++ b/packages/contracts/test/utils/log_decoder.ts
@@ -1,8 +1,8 @@
-import { ContractArtifact } from '@0xproject/sol-compiler';
 import { AbiDecoder, BigNumber } from '@0xproject/utils';
 import { Web3Wrapper } from '@0xproject/web3-wrapper';
 import {
     AbiDefinition,
+    ContractArtifact,
     DecodedLogArgs,
     LogEntry,
     LogWithDecodedArgs,
@@ -16,7 +16,6 @@ import { constants } from './constants';
 
 export class LogDecoder {
     private readonly _web3Wrapper: Web3Wrapper;
-    private readonly _contractAddress: string;
     private readonly _abiDecoder: AbiDecoder;
     public static wrapLogBigNumbers(log: any): any {
         const argNames = _.keys(log.args);
@@ -27,9 +26,8 @@ export class LogDecoder {
             }
         }
     }
-    constructor(web3Wrapper: Web3Wrapper, contractAddress: string) {
+    constructor(web3Wrapper: Web3Wrapper) {
         this._web3Wrapper = web3Wrapper;
-        this._contractAddress = contractAddress;
         const abiArrays: AbiDefinition[][] = [];
         _.forEach(artifacts, (artifact: ContractArtifact) => {
             const compilerOutput = artifact.compilerOutput;
@@ -48,7 +46,6 @@ export class LogDecoder {
     }
     public async getTxWithDecodedLogsAsync(txHash: string): Promise<TransactionReceiptWithDecodedLogs> {
         const tx = await this._web3Wrapper.awaitTransactionSuccessAsync(txHash, constants.AWAIT_TRANSACTION_MINED_MS);
-        tx.logs = _.filter(tx.logs, log => log.address === this._contractAddress);
         tx.logs = _.map(tx.logs, log => this.decodeLogOrThrow(log));
         return tx;
     }
diff --git a/packages/contracts/test/utils/match_order_tester.ts b/packages/contracts/test/utils/match_order_tester.ts
index fa2eabc12..e0c55b834 100644
--- a/packages/contracts/test/utils/match_order_tester.ts
+++ b/packages/contracts/test/utils/match_order_tester.ts
@@ -4,11 +4,20 @@ import { BigNumber } from '@0xproject/utils';
 import * as chai from 'chai';
 import * as _ from 'lodash';
 
+import { TransactionReceiptWithDecodedLogs } from '../../../../node_modules/ethereum-types';
+
 import { chaiSetup } from './chai_setup';
 import { ERC20Wrapper } from './erc20_wrapper';
 import { ERC721Wrapper } from './erc721_wrapper';
 import { ExchangeWrapper } from './exchange_wrapper';
-import { ERC20BalancesByOwner, ERC721TokenIdsByOwner, TransferAmountsByMatchOrders as TransferAmounts } from './types';
+import {
+    ERC20BalancesByOwner,
+    ERC721TokenIdsByOwner,
+    OrderInfo,
+    OrderStatus,
+    TransferAmountsByMatchOrders as TransferAmounts,
+    TransferAmountsLoggedByMatchOrders as LoggedTransferAmounts,
+} from './types';
 
 chaiSetup.configure();
 const expect = chai.expect;
@@ -18,43 +27,107 @@ export class MatchOrderTester {
     private readonly _erc20Wrapper: ERC20Wrapper;
     private readonly _erc721Wrapper: ERC721Wrapper;
     private readonly _feeTokenAddress: string;
-
-    /// @dev Compares a pair of ERC20 balances and a pair of ERC721 token owners.
-    /// @param expectedNewERC20BalancesByOwner Expected ERC20 balances.
-    /// @param realERC20BalancesByOwner Actual ERC20 balances.
-    /// @param expectedNewERC721TokenIdsByOwner Expected ERC721 token owners.
-    /// @param realERC721TokenIdsByOwner Actual ERC20 token owners.
-    /// @return True only if ERC20 balances match and ERC721 token owners match.
-    private static _compareExpectedAndRealBalances(
-        expectedNewERC20BalancesByOwner: ERC20BalancesByOwner,
+    /// @dev Checks values from the logs produced by Exchange.matchOrders against the expected transfer amounts.
+    ///      Values include the amounts transferred from the left/right makers and taker, along with
+    ///      the fees paid on each matched order. These are also the return values of MatchOrders.
+    /// @param signedOrderLeft First matched order.
+    /// @param signedOrderRight Second matched order.
+    /// @param transactionReceipt Transaction receipt and logs produced by Exchange.matchOrders.
+    /// @param takerAddress Address of taker (account that called Exchange.matchOrders)
+    /// @param expectedTransferAmounts Expected amounts transferred as a result of order matching.
+    private static async _assertLogsAsync(
+        signedOrderLeft: SignedOrder,
+        signedOrderRight: SignedOrder,
+        transactionReceipt: TransactionReceiptWithDecodedLogs,
+        takerAddress: string,
+        expectedTransferAmounts: TransferAmounts,
+    ): Promise<void> {
+        // Should have two fill event logs -- one for each order.
+        const transactionFillLogs = _.filter(transactionReceipt.logs, ['event', 'Fill']);
+        expect(transactionFillLogs.length, 'Checking number of logs').to.be.equal(2);
+        // First log is for left fill
+        const leftLog = (transactionFillLogs[0] as any).args as LoggedTransferAmounts;
+        expect(leftLog.makerAddress, 'Checking logged maker address of left order').to.be.equal(
+            signedOrderLeft.makerAddress,
+        );
+        expect(leftLog.takerAddress, 'Checking logged taker address of right order').to.be.equal(takerAddress);
+        const amountBoughtByLeftMaker = new BigNumber(leftLog.takerAssetFilledAmount);
+        const amountSoldByLeftMaker = new BigNumber(leftLog.makerAssetFilledAmount);
+        const feePaidByLeftMaker = new BigNumber(leftLog.makerFeePaid);
+        const feePaidByTakerLeft = new BigNumber(leftLog.takerFeePaid);
+        // Second log is for right fill
+        const rightLog = (transactionFillLogs[1] as any).args as LoggedTransferAmounts;
+        expect(rightLog.makerAddress, 'Checking logged maker address of right order').to.be.equal(
+            signedOrderRight.makerAddress,
+        );
+        expect(rightLog.takerAddress, 'Checking loggerd taker address of right order').to.be.equal(takerAddress);
+        const amountBoughtByRightMaker = new BigNumber(rightLog.takerAssetFilledAmount);
+        const amountSoldByRightMaker = new BigNumber(rightLog.makerAssetFilledAmount);
+        const feePaidByRightMaker = new BigNumber(rightLog.makerFeePaid);
+        const feePaidByTakerRight = new BigNumber(rightLog.takerFeePaid);
+        // Derive amount received by taker
+        const amountReceivedByTaker = amountSoldByLeftMaker.sub(amountBoughtByRightMaker);
+        // Assert log values - left order
+        expect(amountBoughtByLeftMaker, 'Checking logged amount bought by left maker').to.be.bignumber.equal(
+            expectedTransferAmounts.amountBoughtByLeftMaker,
+        );
+        expect(amountSoldByLeftMaker, 'Checking logged amount sold by left maker').to.be.bignumber.equal(
+            expectedTransferAmounts.amountSoldByLeftMaker,
+        );
+        expect(feePaidByLeftMaker, 'Checking logged fee paid by left maker').to.be.bignumber.equal(
+            expectedTransferAmounts.feePaidByLeftMaker,
+        );
+        expect(feePaidByTakerLeft, 'Checking logged fee paid on left order by taker').to.be.bignumber.equal(
+            expectedTransferAmounts.feePaidByTakerLeft,
+        );
+        // Assert log values - right order
+        expect(amountBoughtByRightMaker, 'Checking logged amount bought by right maker').to.be.bignumber.equal(
+            expectedTransferAmounts.amountBoughtByRightMaker,
+        );
+        expect(amountSoldByRightMaker, 'Checking logged amount sold by right maker').to.be.bignumber.equal(
+            expectedTransferAmounts.amountSoldByRightMaker,
+        );
+        expect(feePaidByRightMaker, 'Checking logged fee paid by right maker').to.be.bignumber.equal(
+            expectedTransferAmounts.feePaidByRightMaker,
+        );
+        expect(feePaidByTakerRight, 'Checking logged fee paid on right order by taker').to.be.bignumber.equal(
+            expectedTransferAmounts.feePaidByTakerRight,
+        );
+        // Assert derived amount received by taker
+        expect(amountReceivedByTaker, 'Checking logged amount received by taker').to.be.bignumber.equal(
+            expectedTransferAmounts.amountReceivedByTaker,
+        );
+    }
+    /// @dev Asserts all expected ERC20 and ERC721 account holdings match the real holdings.
+    /// @param expectedERC20BalancesByOwner Expected ERC20 balances.
+    /// @param realERC20BalancesByOwner Real ERC20 balances.
+    /// @param expectedERC721TokenIdsByOwner Expected ERC721 token owners.
+    /// @param realERC721TokenIdsByOwner Real ERC20 token owners.
+    private static async _assertAllKnownBalancesAsync(
+        expectedERC20BalancesByOwner: ERC20BalancesByOwner,
         realERC20BalancesByOwner: ERC20BalancesByOwner,
-        expectedNewERC721TokenIdsByOwner: ERC721TokenIdsByOwner,
+        expectedERC721TokenIdsByOwner: ERC721TokenIdsByOwner,
         realERC721TokenIdsByOwner: ERC721TokenIdsByOwner,
-    ): boolean {
+    ): Promise<void> {
         // ERC20 Balances
-        const doesErc20BalancesMatch = _.isEqual(expectedNewERC20BalancesByOwner, realERC20BalancesByOwner);
-        if (!doesErc20BalancesMatch) {
-            return false;
-        }
+        const areERC20BalancesEqual = _.isEqual(expectedERC20BalancesByOwner, realERC20BalancesByOwner);
+        expect(areERC20BalancesEqual, 'Checking all known ERC20 account balances').to.be.true();
         // ERC721 Token Ids
-        const sortedExpectedNewERC721TokenIdsByOwner = _.mapValues(
-            expectedNewERC721TokenIdsByOwner,
-            tokenIdsByOwner => {
-                _.mapValues(tokenIdsByOwner, tokenIds => {
-                    _.sortBy(tokenIds);
-                });
-            },
-        );
+        const sortedExpectedNewERC721TokenIdsByOwner = _.mapValues(expectedERC721TokenIdsByOwner, tokenIdsByOwner => {
+            _.mapValues(tokenIdsByOwner, tokenIds => {
+                _.sortBy(tokenIds);
+            });
+        });
         const sortedNewERC721TokenIdsByOwner = _.mapValues(realERC721TokenIdsByOwner, tokenIdsByOwner => {
             _.mapValues(tokenIdsByOwner, tokenIds => {
                 _.sortBy(tokenIds);
             });
         });
-        const doesErc721TokenIdsMatch = _.isEqual(
+        const areERC721TokenIdsEqual = _.isEqual(
             sortedExpectedNewERC721TokenIdsByOwner,
             sortedNewERC721TokenIdsByOwner,
         );
-        return doesErc721TokenIdsMatch;
+        expect(areERC721TokenIdsEqual, 'Checking all known ERC721 account balances').to.be.true();
     }
     /// @dev Constructs new MatchOrderTester.
     /// @param exchangeWrapper Used to call to the Exchange.
@@ -72,150 +145,199 @@ export class MatchOrderTester {
         this._erc721Wrapper = erc721Wrapper;
         this._feeTokenAddress = feeTokenAddress;
     }
-    /// @dev Matches two complementary orders and validates results.
-    ///      Validation either succeeds or throws.
+    /// @dev Matches two complementary orders and asserts results.
     /// @param signedOrderLeft First matched order.
     /// @param signedOrderRight Second matched order.
     /// @param takerAddress Address of taker (the address who matched the two orders)
     /// @param erc20BalancesByOwner Current ERC20 balances.
     /// @param erc721TokenIdsByOwner Current ERC721 token owners.
-    /// @param initialTakerAssetFilledAmountLeft Current amount the left order has been filled.
-    /// @param initialTakerAssetFilledAmountRight Current amount the right order has been filled.
+    /// @param expectedTransferAmounts Expected amounts transferred as a result of order matching.
+    /// @param initialLeftOrderFilledAmount How much left order has been filled, prior to matching orders.
+    /// @param initialRightOrderFilledAmount How much the right order has been filled, prior to matching orders.
     /// @return New ERC20 balances & ERC721 token owners.
-    public async matchOrdersAndVerifyBalancesAsync(
+    public async matchOrdersAndAssertEffectsAsync(
         signedOrderLeft: SignedOrder,
         signedOrderRight: SignedOrder,
         takerAddress: string,
         erc20BalancesByOwner: ERC20BalancesByOwner,
         erc721TokenIdsByOwner: ERC721TokenIdsByOwner,
-        initialTakerAssetFilledAmountLeft?: BigNumber,
-        initialTakerAssetFilledAmountRight?: BigNumber,
+        expectedTransferAmounts: TransferAmounts,
+        initialLeftOrderFilledAmount: BigNumber = new BigNumber(0),
+        initialRightOrderFilledAmount: BigNumber = new BigNumber(0),
     ): Promise<[ERC20BalancesByOwner, ERC721TokenIdsByOwner]> {
-        // Verify Left order preconditions
-        const orderTakerAssetFilledAmountLeft = await this._exchangeWrapper.getTakerAssetFilledAmountAsync(
-            orderHashUtils.getOrderHashHex(signedOrderLeft),
-        );
-        const expectedOrderFilledAmountLeft = initialTakerAssetFilledAmountLeft
-            ? initialTakerAssetFilledAmountLeft
-            : new BigNumber(0);
-        expect(expectedOrderFilledAmountLeft).to.be.bignumber.equal(orderTakerAssetFilledAmountLeft);
-        // Verify Right order preconditions
-        const orderTakerAssetFilledAmountRight = await this._exchangeWrapper.getTakerAssetFilledAmountAsync(
-            orderHashUtils.getOrderHashHex(signedOrderRight),
+        // Assert initial order states
+        await this._assertInitialOrderStatesAsync(
+            signedOrderLeft,
+            signedOrderRight,
+            initialLeftOrderFilledAmount,
+            initialRightOrderFilledAmount,
         );
-        const expectedOrderFilledAmountRight = initialTakerAssetFilledAmountRight
-            ? initialTakerAssetFilledAmountRight
-            : new BigNumber(0);
-        expect(expectedOrderFilledAmountRight).to.be.bignumber.equal(orderTakerAssetFilledAmountRight);
         // Match left & right orders
-        await this._exchangeWrapper.matchOrdersAsync(signedOrderLeft, signedOrderRight, takerAddress);
+        const transactionReceipt = await this._exchangeWrapper.matchOrdersAsync(
+            signedOrderLeft,
+            signedOrderRight,
+            takerAddress,
+        );
         const newERC20BalancesByOwner = await this._erc20Wrapper.getBalancesAsync();
         const newERC721TokenIdsByOwner = await this._erc721Wrapper.getBalancesAsync();
-        // Calculate expected balance changes
-        const expectedTransferAmounts = await this._calculateExpectedTransferAmountsAsync(
+        // Assert logs
+        await MatchOrderTester._assertLogsAsync(
             signedOrderLeft,
             signedOrderRight,
-            orderTakerAssetFilledAmountLeft,
-            orderTakerAssetFilledAmountRight,
+            transactionReceipt,
+            takerAddress,
+            expectedTransferAmounts,
         );
-        let expectedERC20BalancesByOwner: ERC20BalancesByOwner;
-        let expectedERC721TokenIdsByOwner: ERC721TokenIdsByOwner;
-        [expectedERC20BalancesByOwner, expectedERC721TokenIdsByOwner] = this._calculateExpectedBalances(
+        // Assert exchange state
+        await this._assertExchangeStateAsync(
             signedOrderLeft,
             signedOrderRight,
-            takerAddress,
-            erc20BalancesByOwner,
-            erc721TokenIdsByOwner,
+            initialLeftOrderFilledAmount,
+            initialRightOrderFilledAmount,
             expectedTransferAmounts,
         );
-        // Assert our expected balances are equal to the actual balances
-        const didExpectedBalancesMatchRealBalances = MatchOrderTester._compareExpectedAndRealBalances(
-            expectedERC20BalancesByOwner,
+        // Assert balances of makers, taker, and fee recipients
+        await this._assertBalancesAsync(
+            signedOrderLeft,
+            signedOrderRight,
+            erc20BalancesByOwner,
+            erc721TokenIdsByOwner,
             newERC20BalancesByOwner,
-            expectedERC721TokenIdsByOwner,
             newERC721TokenIdsByOwner,
+            expectedTransferAmounts,
+            takerAddress,
         );
-        expect(didExpectedBalancesMatchRealBalances).to.be.true();
         return [newERC20BalancesByOwner, newERC721TokenIdsByOwner];
     }
-    /// @dev Calculates expected transfer amounts between order makers, fee recipients, and
-    ///      the taker when two orders are matched.
+    /// @dev Asserts initial exchange state for the left and right orders.
+    /// @param signedOrderLeft First matched order.
+    /// @param signedOrderRight Second matched order.
+    /// @param expectedOrderFilledAmountLeft How much left order has been filled, prior to matching orders.
+    /// @param expectedOrderFilledAmountRight How much the right order has been filled, prior to matching orders.
+    private async _assertInitialOrderStatesAsync(
+        signedOrderLeft: SignedOrder,
+        signedOrderRight: SignedOrder,
+        expectedOrderFilledAmountLeft: BigNumber,
+        expectedOrderFilledAmountRight: BigNumber,
+    ): Promise<void> {
+        // Assert left order initial state
+        const orderTakerAssetFilledAmountLeft = await this._exchangeWrapper.getTakerAssetFilledAmountAsync(
+            orderHashUtils.getOrderHashHex(signedOrderLeft),
+        );
+        expect(orderTakerAssetFilledAmountLeft, 'Checking inital state of left order').to.be.bignumber.equal(
+            expectedOrderFilledAmountLeft,
+        );
+        // Assert right order initial state
+        const orderTakerAssetFilledAmountRight = await this._exchangeWrapper.getTakerAssetFilledAmountAsync(
+            orderHashUtils.getOrderHashHex(signedOrderRight),
+        );
+        expect(orderTakerAssetFilledAmountRight, 'Checking inital state of right order').to.be.bignumber.equal(
+            expectedOrderFilledAmountRight,
+        );
+    }
+    /// @dev Asserts the exchange state against the expected amounts transferred by from matching orders.
     /// @param signedOrderLeft First matched order.
     /// @param signedOrderRight Second matched order.
-    /// @param orderTakerAssetFilledAmountLeft How much left order has been filled, prior to matching orders.
-    /// @param orderTakerAssetFilledAmountRight How much the right order has been filled, prior to matching orders.
+    /// @param initialLeftOrderFilledAmount How much left order has been filled, prior to matching orders.
+    /// @param initialRightOrderFilledAmount How much the right order has been filled, prior to matching orders.
     /// @return TransferAmounts A struct containing the expected transfer amounts.
-    private async _calculateExpectedTransferAmountsAsync(
+    private async _assertExchangeStateAsync(
         signedOrderLeft: SignedOrder,
         signedOrderRight: SignedOrder,
-        orderTakerAssetFilledAmountLeft: BigNumber,
-        orderTakerAssetFilledAmountRight: BigNumber,
-    ): Promise<TransferAmounts> {
+        initialLeftOrderFilledAmount: BigNumber,
+        initialRightOrderFilledAmount: BigNumber,
+        expectedTransferAmounts: TransferAmounts,
+    ): Promise<void> {
+        // Assert state for left order: amount bought by left maker
         let amountBoughtByLeftMaker = await this._exchangeWrapper.getTakerAssetFilledAmountAsync(
             orderHashUtils.getOrderHashHex(signedOrderLeft),
         );
-        amountBoughtByLeftMaker = amountBoughtByLeftMaker.minus(orderTakerAssetFilledAmountLeft);
-        const amountSoldByLeftMaker = amountBoughtByLeftMaker
-            .times(signedOrderLeft.makerAssetAmount)
-            .dividedToIntegerBy(signedOrderLeft.takerAssetAmount);
-        const amountReceivedByRightMaker = amountBoughtByLeftMaker
-            .times(signedOrderRight.takerAssetAmount)
-            .dividedToIntegerBy(signedOrderRight.makerAssetAmount);
-        const amountReceivedByTaker = amountSoldByLeftMaker.minus(amountReceivedByRightMaker);
+        amountBoughtByLeftMaker = amountBoughtByLeftMaker.minus(initialLeftOrderFilledAmount);
+        expect(amountBoughtByLeftMaker, 'Checking exchange state for left order').to.be.bignumber.equal(
+            expectedTransferAmounts.amountBoughtByLeftMaker,
+        );
+        // Assert state for right order: amount bought by right maker
         let amountBoughtByRightMaker = await this._exchangeWrapper.getTakerAssetFilledAmountAsync(
             orderHashUtils.getOrderHashHex(signedOrderRight),
         );
-        amountBoughtByRightMaker = amountBoughtByRightMaker.minus(orderTakerAssetFilledAmountRight);
-        const amountSoldByRightMaker = amountBoughtByRightMaker
-            .times(signedOrderRight.makerAssetAmount)
-            .dividedToIntegerBy(signedOrderRight.takerAssetAmount);
-        const amountReceivedByLeftMaker = amountSoldByRightMaker;
-        const feePaidByLeftMaker = signedOrderLeft.makerFee
-            .times(amountSoldByLeftMaker)
-            .dividedToIntegerBy(signedOrderLeft.makerAssetAmount);
-        const feePaidByRightMaker = signedOrderRight.makerFee
-            .times(amountSoldByRightMaker)
-            .dividedToIntegerBy(signedOrderRight.makerAssetAmount);
-        const feePaidByTakerLeft = signedOrderLeft.takerFee
-            .times(amountSoldByLeftMaker)
-            .dividedToIntegerBy(signedOrderLeft.makerAssetAmount);
-        const feePaidByTakerRight = signedOrderRight.takerFee
-            .times(amountSoldByRightMaker)
-            .dividedToIntegerBy(signedOrderRight.makerAssetAmount);
-        const totalFeePaidByTaker = feePaidByTakerLeft.add(feePaidByTakerRight);
-        const feeReceivedLeft = feePaidByLeftMaker.add(feePaidByTakerLeft);
-        const feeReceivedRight = feePaidByRightMaker.add(feePaidByTakerRight);
-        // Return values
-        const expectedTransferAmounts = {
-            // Left Maker
-            amountBoughtByLeftMaker,
-            amountSoldByLeftMaker,
-            amountReceivedByLeftMaker,
-            feePaidByLeftMaker,
-            // Right Maker
-            amountBoughtByRightMaker,
-            amountSoldByRightMaker,
-            amountReceivedByRightMaker,
-            feePaidByRightMaker,
-            // Taker
-            amountReceivedByTaker,
-            feePaidByTakerLeft,
-            feePaidByTakerRight,
-            totalFeePaidByTaker,
-            // Fee Recipients
-            feeReceivedLeft,
-            feeReceivedRight,
-        };
-        return expectedTransferAmounts;
+        amountBoughtByRightMaker = amountBoughtByRightMaker.minus(initialRightOrderFilledAmount);
+        expect(amountBoughtByRightMaker, 'Checking exchange state for right order').to.be.bignumber.equal(
+            expectedTransferAmounts.amountBoughtByRightMaker,
+        );
+        // Assert left order status
+        const maxAmountBoughtByLeftMaker = signedOrderLeft.takerAssetAmount.minus(initialLeftOrderFilledAmount);
+        const leftOrderInfo: OrderInfo = await this._exchangeWrapper.getOrderInfoAsync(signedOrderLeft);
+        const leftExpectedStatus = expectedTransferAmounts.amountBoughtByLeftMaker.equals(maxAmountBoughtByLeftMaker)
+            ? OrderStatus.FULLY_FILLED
+            : OrderStatus.FILLABLE;
+        expect(leftOrderInfo.orderStatus as OrderStatus, 'Checking exchange status for left order').to.be.equal(
+            leftExpectedStatus,
+        );
+        // Assert right order status
+        const maxAmountBoughtByRightMaker = signedOrderRight.takerAssetAmount.minus(initialRightOrderFilledAmount);
+        const rightOrderInfo: OrderInfo = await this._exchangeWrapper.getOrderInfoAsync(signedOrderRight);
+        const rightExpectedStatus = expectedTransferAmounts.amountBoughtByRightMaker.equals(maxAmountBoughtByRightMaker)
+            ? OrderStatus.FULLY_FILLED
+            : OrderStatus.FILLABLE;
+        expect(rightOrderInfo.orderStatus as OrderStatus, 'Checking exchange status for right order').to.be.equal(
+            rightExpectedStatus,
+        );
+    }
+    /// @dev Asserts account balances after matching orders.
+    /// @param signedOrderLeft First matched order.
+    /// @param signedOrderRight Second matched order.
+    /// @param initialERC20BalancesByOwner ERC20 balances prior to order matching.
+    /// @param initialERC721TokenIdsByOwner ERC721 token owners prior to order matching.
+    /// @param finalERC20BalancesByOwner ERC20 balances after order matching.
+    /// @param finalERC721TokenIdsByOwner ERC721 token owners after order matching.
+    /// @param expectedTransferAmounts Expected amounts transferred as a result of order matching.
+    /// @param takerAddress Address of taker (account that called Exchange.matchOrders).
+    private async _assertBalancesAsync(
+        signedOrderLeft: SignedOrder,
+        signedOrderRight: SignedOrder,
+        initialERC20BalancesByOwner: ERC20BalancesByOwner,
+        initialERC721TokenIdsByOwner: ERC721TokenIdsByOwner,
+        finalERC20BalancesByOwner: ERC20BalancesByOwner,
+        finalERC721TokenIdsByOwner: ERC721TokenIdsByOwner,
+        expectedTransferAmounts: TransferAmounts,
+        takerAddress: string,
+    ): Promise<void> {
+        let expectedERC20BalancesByOwner: ERC20BalancesByOwner;
+        let expectedERC721TokenIdsByOwner: ERC721TokenIdsByOwner;
+        [expectedERC20BalancesByOwner, expectedERC721TokenIdsByOwner] = this._calculateExpectedBalances(
+            signedOrderLeft,
+            signedOrderRight,
+            takerAddress,
+            initialERC20BalancesByOwner,
+            initialERC721TokenIdsByOwner,
+            expectedTransferAmounts,
+        );
+        // Assert balances of makers, taker, and fee recipients
+        await this._assertMakerTakerAndFeeRecipientBalancesAsync(
+            signedOrderLeft,
+            signedOrderRight,
+            expectedERC20BalancesByOwner,
+            finalERC20BalancesByOwner,
+            expectedERC721TokenIdsByOwner,
+            finalERC721TokenIdsByOwner,
+            takerAddress,
+        );
+        // Assert balances for all known accounts
+        await MatchOrderTester._assertAllKnownBalancesAsync(
+            expectedERC20BalancesByOwner,
+            finalERC20BalancesByOwner,
+            expectedERC721TokenIdsByOwner,
+            finalERC721TokenIdsByOwner,
+        );
     }
     /// @dev Calculates the expected balances of order makers, fee recipients, and the taker,
     ///      as a result of matching two orders.
-    /// @param signedOrderLeft First matched order.
+    /// @param signedOrderRight First matched order.
     /// @param signedOrderRight Second matched order.
     /// @param takerAddress Address of taker (the address who matched the two orders)
     /// @param erc20BalancesByOwner Current ERC20 balances.
     /// @param erc721TokenIdsByOwner Current ERC721 token owners.
-    /// @param expectedTransferAmounts A struct containing the expected transfer amounts.
+    /// @param expectedTransferAmounts Expected amounts transferred as a result of order matching.
     /// @return Expected ERC20 balances & ERC721 token owners after orders have been matched.
     private _calculateExpectedBalances(
         signedOrderLeft: SignedOrder,
@@ -247,7 +369,7 @@ export class MatchOrderTester {
             expectedNewERC20BalancesByOwner[makerAddressRight][
                 takerAssetAddressRight
             ] = expectedNewERC20BalancesByOwner[makerAddressRight][takerAssetAddressRight].add(
-                expectedTransferAmounts.amountReceivedByRightMaker,
+                expectedTransferAmounts.amountBoughtByRightMaker,
             );
             // Taker
             expectedNewERC20BalancesByOwner[takerAddress][makerAssetAddressLeft] = expectedNewERC20BalancesByOwner[
@@ -277,7 +399,7 @@ export class MatchOrderTester {
             // Left Maker
             expectedNewERC20BalancesByOwner[makerAddressLeft][takerAssetAddressLeft] = expectedNewERC20BalancesByOwner[
                 makerAddressLeft
-            ][takerAssetAddressLeft].add(expectedTransferAmounts.amountReceivedByLeftMaker);
+            ][takerAssetAddressLeft].add(expectedTransferAmounts.amountBoughtByLeftMaker);
             // Right Maker
             expectedNewERC20BalancesByOwner[makerAddressRight][
                 makerAssetAddressRight
@@ -307,20 +429,138 @@ export class MatchOrderTester {
         // Taker Fees
         expectedNewERC20BalancesByOwner[takerAddress][this._feeTokenAddress] = expectedNewERC20BalancesByOwner[
             takerAddress
-        ][this._feeTokenAddress].minus(expectedTransferAmounts.totalFeePaidByTaker);
+        ][this._feeTokenAddress].minus(
+            expectedTransferAmounts.feePaidByTakerLeft.add(expectedTransferAmounts.feePaidByTakerRight),
+        );
         // Left Fee Recipient Fees
         expectedNewERC20BalancesByOwner[feeRecipientAddressLeft][
             this._feeTokenAddress
         ] = expectedNewERC20BalancesByOwner[feeRecipientAddressLeft][this._feeTokenAddress].add(
-            expectedTransferAmounts.feeReceivedLeft,
+            expectedTransferAmounts.feePaidByLeftMaker.add(expectedTransferAmounts.feePaidByTakerLeft),
         );
         // Right Fee Recipient Fees
         expectedNewERC20BalancesByOwner[feeRecipientAddressRight][
             this._feeTokenAddress
         ] = expectedNewERC20BalancesByOwner[feeRecipientAddressRight][this._feeTokenAddress].add(
-            expectedTransferAmounts.feeReceivedRight,
+            expectedTransferAmounts.feePaidByRightMaker.add(expectedTransferAmounts.feePaidByTakerRight),
         );
 
         return [expectedNewERC20BalancesByOwner, expectedNewERC721TokenIdsByOwner];
     }
-}
+    /// @dev Asserts ERC20 account balances and ERC721 token holdings that result from order matching.
+    ///      Specifically checks balances of makers, taker and fee recipients.
+    /// @param signedOrderLeft First matched order.
+    /// @param signedOrderRight Second matched order.
+    /// @param expectedERC20BalancesByOwner Expected ERC20 balances.
+    /// @param realERC20BalancesByOwner Real ERC20 balances.
+    /// @param expectedERC721TokenIdsByOwner Expected ERC721 token owners.
+    /// @param realERC721TokenIdsByOwner Real ERC20 token owners.
+    /// @param takerAddress Address of taker (account that called Exchange.matchOrders).
+    private async _assertMakerTakerAndFeeRecipientBalancesAsync(
+        signedOrderLeft: SignedOrder,
+        signedOrderRight: SignedOrder,
+        expectedERC20BalancesByOwner: ERC20BalancesByOwner,
+        realERC20BalancesByOwner: ERC20BalancesByOwner,
+        expectedERC721TokenIdsByOwner: ERC721TokenIdsByOwner,
+        realERC721TokenIdsByOwner: ERC721TokenIdsByOwner,
+        takerAddress: string,
+    ): Promise<void> {
+        // Individual balance comparisons
+        const makerAssetProxyIdLeft = assetDataUtils.decodeAssetProxyId(signedOrderLeft.makerAssetData);
+        const makerERC20AssetDataLeft =
+            makerAssetProxyIdLeft === AssetProxyId.ERC20
+                ? assetDataUtils.decodeERC20AssetData(signedOrderLeft.makerAssetData)
+                : assetDataUtils.decodeERC721AssetData(signedOrderLeft.makerAssetData);
+        const makerAssetAddressLeft = makerERC20AssetDataLeft.tokenAddress;
+        const makerAssetProxyIdRight = assetDataUtils.decodeAssetProxyId(signedOrderRight.makerAssetData);
+        const makerERC20AssetDataRight =
+            makerAssetProxyIdRight === AssetProxyId.ERC20
+                ? assetDataUtils.decodeERC20AssetData(signedOrderRight.makerAssetData)
+                : assetDataUtils.decodeERC721AssetData(signedOrderRight.makerAssetData);
+        const makerAssetAddressRight = makerERC20AssetDataRight.tokenAddress;
+        if (makerAssetProxyIdLeft === AssetProxyId.ERC20) {
+            expect(
+                realERC20BalancesByOwner[signedOrderLeft.makerAddress][makerAssetAddressLeft],
+                'Checking left maker egress ERC20 account balance',
+            ).to.be.bignumber.equal(expectedERC20BalancesByOwner[signedOrderLeft.makerAddress][makerAssetAddressLeft]);
+            expect(
+                realERC20BalancesByOwner[signedOrderRight.makerAddress][makerAssetAddressLeft],
+                'Checking right maker ingress ERC20 account balance',
+            ).to.be.bignumber.equal(expectedERC20BalancesByOwner[signedOrderRight.makerAddress][makerAssetAddressLeft]);
+            expect(
+                realERC20BalancesByOwner[takerAddress][makerAssetAddressLeft],
+                'Checking taker ingress ERC20 account balance',
+            ).to.be.bignumber.equal(expectedERC20BalancesByOwner[takerAddress][makerAssetAddressLeft]);
+        } else if (makerAssetProxyIdLeft === AssetProxyId.ERC721) {
+            expect(
+                realERC721TokenIdsByOwner[signedOrderLeft.makerAddress][makerAssetAddressLeft].sort(),
+                'Checking left maker egress ERC721 account holdings',
+            ).to.be.deep.equal(
+                expectedERC721TokenIdsByOwner[signedOrderLeft.makerAddress][makerAssetAddressLeft].sort(),
+            );
+            expect(
+                realERC721TokenIdsByOwner[signedOrderRight.makerAddress][makerAssetAddressLeft].sort(),
+                'Checking right maker ERC721 account holdings',
+            ).to.be.deep.equal(
+                expectedERC721TokenIdsByOwner[signedOrderRight.makerAddress][makerAssetAddressLeft].sort(),
+            );
+            expect(
+                realERC721TokenIdsByOwner[takerAddress][makerAssetAddressLeft].sort(),
+                'Checking taker ingress ERC721 account holdings',
+            ).to.be.deep.equal(expectedERC721TokenIdsByOwner[takerAddress][makerAssetAddressLeft].sort());
+        } else {
+            throw new Error(`Unhandled Asset Proxy ID: ${makerAssetProxyIdLeft}`);
+        }
+        if (makerAssetProxyIdRight === AssetProxyId.ERC20) {
+            expect(
+                realERC20BalancesByOwner[signedOrderLeft.makerAddress][makerAssetAddressRight],
+                'Checking left maker ingress ERC20 account balance',
+            ).to.be.bignumber.equal(expectedERC20BalancesByOwner[signedOrderLeft.makerAddress][makerAssetAddressRight]);
+            expect(
+                realERC20BalancesByOwner[signedOrderRight.makerAddress][makerAssetAddressRight],
+                'Checking right maker egress ERC20 account balance',
+            ).to.be.bignumber.equal(
+                expectedERC20BalancesByOwner[signedOrderRight.makerAddress][makerAssetAddressRight],
+            );
+        } else if (makerAssetProxyIdRight === AssetProxyId.ERC721) {
+            expect(
+                realERC721TokenIdsByOwner[signedOrderLeft.makerAddress][makerAssetAddressRight].sort(),
+                'Checking left maker ingress ERC721 account holdings',
+            ).to.be.deep.equal(
+                expectedERC721TokenIdsByOwner[signedOrderLeft.makerAddress][makerAssetAddressRight].sort(),
+            );
+            expect(
+                realERC721TokenIdsByOwner[signedOrderRight.makerAddress][makerAssetAddressRight],
+                'Checking right maker agress ERC721 account holdings',
+            ).to.be.deep.equal(expectedERC721TokenIdsByOwner[signedOrderRight.makerAddress][makerAssetAddressRight]);
+        } else {
+            throw new Error(`Unhandled Asset Proxy ID: ${makerAssetProxyIdRight}`);
+        }
+        // Paid fees
+        expect(
+            realERC20BalancesByOwner[signedOrderLeft.makerAddress][this._feeTokenAddress],
+            'Checking left maker egress ERC20 account fees',
+        ).to.be.bignumber.equal(expectedERC20BalancesByOwner[signedOrderLeft.makerAddress][this._feeTokenAddress]);
+        expect(
+            realERC20BalancesByOwner[signedOrderRight.makerAddress][this._feeTokenAddress],
+            'Checking right maker egress ERC20 account fees',
+        ).to.be.bignumber.equal(expectedERC20BalancesByOwner[signedOrderRight.makerAddress][this._feeTokenAddress]);
+        expect(
+            realERC20BalancesByOwner[takerAddress][this._feeTokenAddress],
+            'Checking taker egress ERC20 account fees',
+        ).to.be.bignumber.equal(expectedERC20BalancesByOwner[takerAddress][this._feeTokenAddress]);
+        // Received fees
+        expect(
+            realERC20BalancesByOwner[signedOrderLeft.feeRecipientAddress][this._feeTokenAddress],
+            'Checking left fee recipient ingress ERC20 account fees',
+        ).to.be.bignumber.equal(
+            expectedERC20BalancesByOwner[signedOrderLeft.feeRecipientAddress][this._feeTokenAddress],
+        );
+        expect(
+            realERC20BalancesByOwner[signedOrderRight.feeRecipientAddress][this._feeTokenAddress],
+            'Checking right fee receipient ingress ERC20 account fees',
+        ).to.be.bignumber.equal(
+            expectedERC20BalancesByOwner[signedOrderRight.feeRecipientAddress][this._feeTokenAddress],
+        );
+    }
+} // tslint:disable-line:max-file-line-count
diff --git a/packages/contracts/test/utils/multi_sig_wrapper.ts b/packages/contracts/test/utils/multi_sig_wrapper.ts
index 8c8055d4a..e12a58695 100644
--- a/packages/contracts/test/utils/multi_sig_wrapper.ts
+++ b/packages/contracts/test/utils/multi_sig_wrapper.ts
@@ -6,7 +6,6 @@ import * as _ from 'lodash';
 import { AssetProxyOwnerContract } from '../../generated_contract_wrappers/asset_proxy_owner';
 import { MultiSigWalletContract } from '../../generated_contract_wrappers/multi_sig_wallet';
 
-import { constants } from './constants';
 import { LogDecoder } from './log_decoder';
 
 export class MultiSigWrapper {
@@ -16,7 +15,7 @@ export class MultiSigWrapper {
     constructor(multiSigContract: MultiSigWalletContract, provider: Provider) {
         this._multiSig = multiSigContract;
         this._web3Wrapper = new Web3Wrapper(provider);
-        this._logDecoder = new LogDecoder(this._web3Wrapper, this._multiSig.address);
+        this._logDecoder = new LogDecoder(this._web3Wrapper);
     }
     public async submitTransactionAsync(
         destination: string,
@@ -36,10 +35,19 @@ export class MultiSigWrapper {
         const tx = await this._logDecoder.getTxWithDecodedLogsAsync(txHash);
         return tx;
     }
-    public async executeTransactionAsync(txId: BigNumber, from: string): Promise<TransactionReceiptWithDecodedLogs> {
+    public async revokeConfirmationAsync(txId: BigNumber, from: string): Promise<TransactionReceiptWithDecodedLogs> {
+        const txHash = await this._multiSig.revokeConfirmation.sendTransactionAsync(txId, { from });
+        const tx = await this._logDecoder.getTxWithDecodedLogsAsync(txHash);
+        return tx;
+    }
+    public async executeTransactionAsync(
+        txId: BigNumber,
+        from: string,
+        opts: { gas?: number } = {},
+    ): Promise<TransactionReceiptWithDecodedLogs> {
         const txHash = await this._multiSig.executeTransaction.sendTransactionAsync(txId, {
             from,
-            gas: constants.MAX_EXECUTE_TRANSACTION_GAS,
+            gas: opts.gas,
         });
         const tx = await this._logDecoder.getTxWithDecodedLogsAsync(txHash);
         return tx;
@@ -52,7 +60,6 @@ export class MultiSigWrapper {
         const txHash = await (this
             ._multiSig as AssetProxyOwnerContract).executeRemoveAuthorizedAddressAtIndex.sendTransactionAsync(txId, {
             from,
-            gas: constants.MAX_EXECUTE_TRANSACTION_GAS,
         });
         const tx = await this._logDecoder.getTxWithDecodedLogsAsync(txHash);
         return tx;
diff --git a/packages/contracts/test/utils/order_factory_from_scenario.ts b/packages/contracts/test/utils/order_factory_from_scenario.ts
index a908140b9..8e04db588 100644
--- a/packages/contracts/test/utils/order_factory_from_scenario.ts
+++ b/packages/contracts/test/utils/order_factory_from_scenario.ts
@@ -21,6 +21,8 @@ const POINT_ONE_UNITS_EIGHTEEN_DECIMALS = new BigNumber(100_000_000_000_000_000)
 const POINT_ZERO_FIVE_UNITS_EIGHTEEN_DECIMALS = new BigNumber(50_000_000_000_000_000);
 const TEN_UNITS_FIVE_DECIMALS = new BigNumber(1_000_000);
 const FIVE_UNITS_FIVE_DECIMALS = new BigNumber(500_000);
+const TEN_UNITS_ZERO_DECIMALS = new BigNumber(10);
+const ONE_THOUSAND_UNITS_ZERO_DECIMALS = new BigNumber(1000);
 const ONE_NFT_UNIT = new BigNumber(1);
 
 export class OrderFactoryFromScenario {
@@ -28,6 +30,7 @@ export class OrderFactoryFromScenario {
     private readonly _zrxAddress: string;
     private readonly _nonZrxERC20EighteenDecimalTokenAddresses: string[];
     private readonly _erc20FiveDecimalTokenAddresses: string[];
+    private readonly _erc20ZeroDecimalTokenAddresses: string[];
     private readonly _erc721Token: DummyERC721TokenContract;
     private readonly _erc721Balances: ERC721TokenIdsByOwner;
     private readonly _exchangeAddress: string;
@@ -36,6 +39,7 @@ export class OrderFactoryFromScenario {
         zrxAddress: string,
         nonZrxERC20EighteenDecimalTokenAddresses: string[],
         erc20FiveDecimalTokenAddresses: string[],
+        erc20ZeroDecimalTokenAddresses: string[],
         erc721Token: DummyERC721TokenContract,
         erc721Balances: ERC721TokenIdsByOwner,
         exchangeAddress: string,
@@ -44,6 +48,7 @@ export class OrderFactoryFromScenario {
         this._zrxAddress = zrxAddress;
         this._nonZrxERC20EighteenDecimalTokenAddresses = nonZrxERC20EighteenDecimalTokenAddresses;
         this._erc20FiveDecimalTokenAddresses = erc20FiveDecimalTokenAddresses;
+        this._erc20ZeroDecimalTokenAddresses = erc20ZeroDecimalTokenAddresses;
         this._erc721Token = erc721Token;
         this._erc721Balances = erc721Balances;
         this._exchangeAddress = exchangeAddress;
@@ -89,6 +94,9 @@ export class OrderFactoryFromScenario {
                     erc721MakerAssetIds[0],
                 );
                 break;
+            case AssetDataScenario.ERC20ZeroDecimals:
+                makerAssetData = assetDataUtils.encodeERC20AssetData(this._erc20ZeroDecimalTokenAddresses[0]);
+                break;
             default:
                 throw errorUtils.spawnSwitchErr('AssetDataScenario', orderScenario.makerAssetDataScenario);
         }
@@ -109,6 +117,9 @@ export class OrderFactoryFromScenario {
                     erc721TakerAssetIds[0],
                 );
                 break;
+            case AssetDataScenario.ERC20ZeroDecimals:
+                takerAssetData = assetDataUtils.encodeERC20AssetData(this._erc20ZeroDecimalTokenAddresses[1]);
+                break;
             default:
                 throw errorUtils.spawnSwitchErr('AssetDataScenario', orderScenario.takerAssetDataScenario);
         }
@@ -126,6 +137,9 @@ export class OrderFactoryFromScenario {
                     case AssetDataScenario.ERC721:
                         makerAssetAmount = ONE_NFT_UNIT;
                         break;
+                    case AssetDataScenario.ERC20ZeroDecimals:
+                        makerAssetAmount = ONE_THOUSAND_UNITS_ZERO_DECIMALS;
+                        break;
                     default:
                         throw errorUtils.spawnSwitchErr('AssetDataScenario', orderScenario.makerAssetDataScenario);
                 }
@@ -142,6 +156,9 @@ export class OrderFactoryFromScenario {
                     case AssetDataScenario.ERC721:
                         makerAssetAmount = ONE_NFT_UNIT;
                         break;
+                    case AssetDataScenario.ERC20ZeroDecimals:
+                        makerAssetAmount = TEN_UNITS_ZERO_DECIMALS;
+                        break;
                     default:
                         throw errorUtils.spawnSwitchErr('AssetDataScenario', orderScenario.makerAssetDataScenario);
                 }
@@ -166,6 +183,9 @@ export class OrderFactoryFromScenario {
                     case AssetDataScenario.ERC721:
                         takerAssetAmount = ONE_NFT_UNIT;
                         break;
+                    case AssetDataScenario.ERC20ZeroDecimals:
+                        takerAssetAmount = ONE_THOUSAND_UNITS_ZERO_DECIMALS;
+                        break;
                     default:
                         throw errorUtils.spawnSwitchErr('AssetDataScenario', orderScenario.takerAssetDataScenario);
                 }
@@ -182,6 +202,9 @@ export class OrderFactoryFromScenario {
                     case AssetDataScenario.ERC721:
                         takerAssetAmount = ONE_NFT_UNIT;
                         break;
+                    case AssetDataScenario.ERC20ZeroDecimals:
+                        takerAssetAmount = TEN_UNITS_ZERO_DECIMALS;
+                        break;
                     default:
                         throw errorUtils.spawnSwitchErr('AssetDataScenario', orderScenario.takerAssetDataScenario);
                 }
diff --git a/packages/contracts/test/utils/order_utils.ts b/packages/contracts/test/utils/order_utils.ts
index 019f6e74b..444e27c44 100644
--- a/packages/contracts/test/utils/order_utils.ts
+++ b/packages/contracts/test/utils/order_utils.ts
@@ -5,7 +5,7 @@ import { constants } from './constants';
 import { CancelOrder, MatchOrder } from './types';
 
 export const orderUtils = {
-    getPartialAmount(numerator: BigNumber, denominator: BigNumber, target: BigNumber): BigNumber {
+    getPartialAmountFloor(numerator: BigNumber, denominator: BigNumber, target: BigNumber): BigNumber {
         const partialAmount = numerator
             .mul(target)
             .div(denominator)
diff --git a/packages/contracts/test/utils/test_with_reference.ts b/packages/contracts/test/utils/test_with_reference.ts
index 599b1eed4..b80be4a6c 100644
--- a/packages/contracts/test/utils/test_with_reference.ts
+++ b/packages/contracts/test/utils/test_with_reference.ts
@@ -6,6 +6,34 @@ import { chaiSetup } from './chai_setup';
 chaiSetup.configure();
 const expect = chai.expect;
 
+class Value<T> {
+    public value: T;
+    constructor(value: T) {
+        this.value = value;
+    }
+}
+
+// tslint:disable-next-line: max-classes-per-file
+class ErrorMessage {
+    public error: string;
+    constructor(message: string) {
+        this.error = message;
+    }
+}
+
+type PromiseResult<T> = Value<T> | ErrorMessage;
+
+// TODO(albrow): This seems like a generic utility function that could exist in
+// lodash. We should replace it by a library implementation, or move it to our
+// own.
+async function evaluatePromise<T>(promise: Promise<T>): Promise<PromiseResult<T>> {
+    try {
+        return new Value<T>(await promise);
+    } catch (e) {
+        return new ErrorMessage(e.message);
+    }
+}
+
 export async function testWithReferenceFuncAsync<P0, R>(
     referenceFunc: (p0: P0) => Promise<R>,
     testFunc: (p0: P0) => Promise<R>,
@@ -64,39 +92,31 @@ export async function testWithReferenceFuncAsync(
     testFuncAsync: (...args: any[]) => Promise<any>,
     values: any[],
 ): Promise<void> {
-    let expectedResult: any;
-    let expectedErr: string | undefined;
-    try {
-        expectedResult = await referenceFuncAsync(...values);
-    } catch (e) {
-        expectedErr = e.message;
-    }
-    let actualResult: any | undefined;
-    try {
-        actualResult = await testFuncAsync(...values);
-        if (!_.isUndefined(expectedErr)) {
+    // Measure correct behaviour
+    const expected = await evaluatePromise(referenceFuncAsync(...values));
+
+    // Measure actual behaviour
+    const actual = await evaluatePromise(testFuncAsync(...values));
+
+    // Compare behaviour
+    if (expected instanceof ErrorMessage) {
+        // If we expected an error, check if the actual error message contains the
+        // expected error message.
+        if (!(actual instanceof ErrorMessage)) {
             throw new Error(
-                `Expected error containing ${expectedErr} but got no error\n\tTest case: ${_getTestCaseString(
+                `Expected error containing ${expected.error} but got no error\n\tTest case: ${_getTestCaseString(
                     referenceFuncAsync,
                     values,
                 )}`,
             );
         }
-    } catch (e) {
-        if (_.isUndefined(expectedErr)) {
-            throw new Error(`${e.message}\n\tTest case: ${_getTestCaseString(referenceFuncAsync, values)}`);
-        } else {
-            expect(e.message).to.contain(
-                expectedErr,
-                `${e.message}\n\tTest case: ${_getTestCaseString(referenceFuncAsync, values)}`,
-            );
-        }
-    }
-    if (!_.isUndefined(actualResult) && !_.isUndefined(expectedResult)) {
-        expect(actualResult).to.deep.equal(
-            expectedResult,
-            `Test case: ${_getTestCaseString(referenceFuncAsync, values)}`,
+        expect(actual.error).to.contain(
+            expected.error,
+            `${actual.error}\n\tTest case: ${_getTestCaseString(referenceFuncAsync, values)}`,
         );
+    } else {
+        // If we do not expect an error, compare actual and expected directly.
+        expect(actual).to.deep.equal(expected, `Test case ${_getTestCaseString(referenceFuncAsync, values)}`);
     }
 }
 
diff --git a/packages/contracts/test/utils/transaction_factory.ts b/packages/contracts/test/utils/transaction_factory.ts
index 281c1e30d..8465a6a30 100644
--- a/packages/contracts/test/utils/transaction_factory.ts
+++ b/packages/contracts/test/utils/transaction_factory.ts
@@ -1,4 +1,4 @@
-import { EIP712Schema, EIP712Types, EIP712Utils, generatePseudoRandomSalt } from '@0xproject/order-utils';
+import { EIP712Schema, EIP712Types, eip712Utils, generatePseudoRandomSalt } from '@0xproject/order-utils';
 import { SignatureType } from '@0xproject/types';
 import * as ethUtil from 'ethereumjs-util';
 
@@ -31,11 +31,11 @@ export class TransactionFactory {
             signerAddress,
             data,
         };
-        const executeTransactionHashBuff = EIP712Utils.structHash(
+        const executeTransactionHashBuff = eip712Utils.structHash(
             EIP712_ZEROEX_TRANSACTION_SCHEMA,
             executeTransactionData,
         );
-        const txHash = EIP712Utils.createEIP712Message(executeTransactionHashBuff, this._exchangeAddress);
+        const txHash = eip712Utils.createEIP712Message(executeTransactionHashBuff, this._exchangeAddress);
         const signature = signingUtils.signMessage(txHash, this._privateKey, signatureType);
         const signedTx = {
             exchangeAddress: this._exchangeAddress,
diff --git a/packages/contracts/test/utils/types.ts b/packages/contracts/test/utils/types.ts
index 67313b647..598fb5393 100644
--- a/packages/contracts/test/utils/types.ts
+++ b/packages/contracts/test/utils/types.ts
@@ -117,21 +117,24 @@ export interface TransferAmountsByMatchOrders {
     // Left Maker
     amountBoughtByLeftMaker: BigNumber;
     amountSoldByLeftMaker: BigNumber;
-    amountReceivedByLeftMaker: BigNumber;
     feePaidByLeftMaker: BigNumber;
     // Right Maker
     amountBoughtByRightMaker: BigNumber;
     amountSoldByRightMaker: BigNumber;
-    amountReceivedByRightMaker: BigNumber;
     feePaidByRightMaker: BigNumber;
     // Taker
     amountReceivedByTaker: BigNumber;
     feePaidByTakerLeft: BigNumber;
     feePaidByTakerRight: BigNumber;
-    totalFeePaidByTaker: BigNumber;
-    // Fee Recipients
-    feeReceivedLeft: BigNumber;
-    feeReceivedRight: BigNumber;
+}
+
+export interface TransferAmountsLoggedByMatchOrders {
+    makerAddress: string;
+    takerAddress: string;
+    makerAssetFilledAmount: string;
+    takerAssetFilledAmount: string;
+    makerFeePaid: string;
+    takerFeePaid: string;
 }
 
 export interface OrderInfo {
@@ -177,10 +180,11 @@ export enum ExpirationTimeSecondsScenario {
 }
 
 export enum AssetDataScenario {
-    ERC721 = 'ERC721',
+    ERC20ZeroDecimals = 'ERC20_ZERO_DECIMALS',
     ZRXFeeToken = 'ZRX_FEE_TOKEN',
     ERC20FiveDecimals = 'ERC20_FIVE_DECIMALS',
     ERC20NonZRXEighteenDecimals = 'ERC20_NON_ZRX_EIGHTEEN_DECIMALS',
+    ERC721 = 'ERC721',
 }
 
 export enum TakerAssetFillAmountScenario {
diff --git a/packages/contracts/test/utils/web3_wrapper.ts b/packages/contracts/test/utils/web3_wrapper.ts
index acb3103b7..d1cd3d387 100644
--- a/packages/contracts/test/utils/web3_wrapper.ts
+++ b/packages/contracts/test/utils/web3_wrapper.ts
@@ -1,5 +1,5 @@
 import { devConstants, env, EnvVars, web3Factory } from '@0xproject/dev-utils';
-import { prependSubprovider } from '@0xproject/subproviders';
+import { prependSubprovider, Web3ProviderEngine } from '@0xproject/subproviders';
 import { logUtils } from '@0xproject/utils';
 import { Web3Wrapper } from '@0xproject/web3-wrapper';
 import * as _ from 'lodash';
@@ -47,7 +47,7 @@ const ganacheConfigs = {
 };
 const providerConfigs = testProvider === ProviderType.Ganache ? ganacheConfigs : gethConfigs;
 
-export const provider = web3Factory.getRpcProvider(providerConfigs);
+export const provider: Web3ProviderEngine = web3Factory.getRpcProvider(providerConfigs);
 const isCoverageEnabled = env.parseBoolean(EnvVars.SolidityCoverage);
 const isProfilerEnabled = env.parseBoolean(EnvVars.SolidityProfiler);
 const isRevertTraceEnabled = env.parseBoolean(EnvVars.SolidityRevertTrace);