Merge branch 'master' into addEventSubscriptions

# Conflicts:
#	src/contract_wrappers/exchange_wrapper.ts
#	src/types.ts
#	test/exchange_wrapper_test.ts

8 files changed, 378 insertions, 150 deletions

diff --git a/src/0x.js.ts b/src/0x.js.ts
index 0cda7732d..850827fee 100644
--- a/src/0x.js.ts
+++ b/src/0x.js.ts
@@ -135,7 +135,7 @@ export class ZeroEx {
         return senderAccountIfExists;
     }
     /**
-     * Computes the orderHash given the order parameters and returns it as a hex encoded string.
+     * Computes the orderHash for a given order and returns it as a hex encoded string.
      */
     public async getOrderHashHexAsync(order: Order|SignedOrder): Promise<string> {
         const exchangeContractAddr = await this.getExchangeAddressAsync();
diff --git a/src/contract_wrappers/exchange_wrapper.ts b/src/contract_wrappers/exchange_wrapper.ts
index de614f471..b67fd33ac 100644
--- a/src/contract_wrappers/exchange_wrapper.ts
+++ b/src/contract_wrappers/exchange_wrapper.ts
@@ -7,7 +7,6 @@ import {
     ExchangeContract,
     ExchangeContractErrCodes,
     ExchangeContractErrs,
-    FillOrderValidationErrs,
     OrderValues,
     OrderAddresses,
     SignedOrder,
@@ -19,6 +18,7 @@ import {
     CreateContractEvent,
     ContractEventObj,
     EventCallback,
+    ContractResponse,
 } from '../types';
 import {assert} from '../utils/assert';
 import {utils} from '../utils/utils';
@@ -27,18 +27,17 @@ import * as ExchangeArtifacts from '../artifacts/Exchange.json';
 import {ecSignatureSchema} from '../schemas/ec_signature_schema';
 import {signedOrderSchema} from '../schemas/order_schemas';
 import {SchemaValidator} from '../utils/schema_validator';
-import {ContractResponse} from '../types';
 import {constants} from '../utils/constants';
 import {TokenWrapper} from './token_wrapper';
 
 export class ExchangeWrapper extends ContractWrapper {
     private exchangeContractErrCodesToMsg = {
-        [ExchangeContractErrCodes.ERROR_FILL_EXPIRED]: ExchangeContractErrs.ORDER_EXPIRED,
-        [ExchangeContractErrCodes.ERROR_CANCEL_EXPIRED]: ExchangeContractErrs.ORDER_EXPIRED,
+        [ExchangeContractErrCodes.ERROR_FILL_EXPIRED]: ExchangeContractErrs.ORDER_FILL_EXPIRED,
+        [ExchangeContractErrCodes.ERROR_CANCEL_EXPIRED]: ExchangeContractErrs.ORDER_FILL_EXPIRED,
         [ExchangeContractErrCodes.ERROR_FILL_NO_VALUE]: ExchangeContractErrs.ORDER_REMAINING_FILL_AMOUNT_ZERO,
         [ExchangeContractErrCodes.ERROR_CANCEL_NO_VALUE]: ExchangeContractErrs.ORDER_REMAINING_FILL_AMOUNT_ZERO,
-        [ExchangeContractErrCodes.ERROR_FILL_TRUNCATION]: ExchangeContractErrs.ORDER_ROUNDING_ERROR,
-        [ExchangeContractErrCodes.ERROR_FILL_BALANCE_ALLOWANCE]: ExchangeContractErrs.ORDER_BALANCE_ALLOWANCE_ERROR,
+        [ExchangeContractErrCodes.ERROR_FILL_TRUNCATION]: ExchangeContractErrs.ORDER_FILL_ROUNDING_ERROR,
+        [ExchangeContractErrCodes.ERROR_FILL_BALANCE_ALLOWANCE]: ExchangeContractErrs.FILL_BALANCE_ALLOWANCE_ERROR,
     };
     private exchangeContractIfExists?: ExchangeContract;
     private exchangeLogEventObjs: ContractEventObj[];
@@ -112,22 +111,24 @@ export class ExchangeWrapper extends ContractWrapper {
         return cancelledAmountInBaseUnits;
     }
     /**
-     * Fills a signed order with a fillAmount denominated in baseUnits of the taker token. The caller can
-     * decide whether they want the call to throw if the balance/allowance checks fail by setting
-     * shouldCheckTransfer to false. If set to true, the call will fail without throwing, preserving gas costs.
+     * Fills a signed order with a fillAmount denominated in baseUnits of the taker token.
+     * Since the order in which transactions are included in the next block is indeterminate, race-conditions
+     * could arise where a users balance or allowance changes before the fillOrder executes. Because of this,
+     * we allow you to specify `shouldCheckTransfer`. If true, the smart contract will not throw if while
+     * executing, the parties do not have sufficient balances/allowances, preserving gas costs. Setting it to
+     * false forgoes this check and causes the smart contract to throw instead.
      */
-    public async fillOrderAsync(signedOrder: SignedOrder, fillTakerAmountInBaseUnits: BigNumber.BigNumber,
+    public async fillOrderAsync(signedOrder: SignedOrder, fillTakerAmount: BigNumber.BigNumber,
                                 shouldCheckTransfer: boolean): Promise<void> {
         assert.doesConformToSchema('signedOrder',
                                    SchemaValidator.convertToJSONSchemaCompatibleObject(signedOrder as object),
                                    signedOrderSchema);
-        assert.isBigNumber('fillTakerAmountInBaseUnits', fillTakerAmountInBaseUnits);
+        assert.isBigNumber('fillTakerAmount', fillTakerAmount);
         assert.isBoolean('shouldCheckTransfer', shouldCheckTransfer);
 
         const senderAddress = await this.web3Wrapper.getSenderAddressOrThrowAsync();
-        await this.validateFillOrderAsync(signedOrder, fillTakerAmountInBaseUnits, senderAddress);
-
         const exchangeInstance = await this.getExchangeContractAsync();
+        await this.validateFillOrderAndThrowIfInvalidAsync(signedOrder, fillTakerAmount, senderAddress);
 
         const orderAddresses: OrderAddresses = [
             signedOrder.maker,
@@ -147,7 +148,7 @@ export class ExchangeWrapper extends ContractWrapper {
         const gas = await exchangeInstance.fill.estimateGas(
             orderAddresses,
             orderValues,
-            fillTakerAmountInBaseUnits,
+            fillTakerAmount,
             shouldCheckTransfer,
             signedOrder.ecSignature.v,
             signedOrder.ecSignature.r,
@@ -159,7 +160,7 @@ export class ExchangeWrapper extends ContractWrapper {
         const response: ContractResponse = await exchangeInstance.fill(
             orderAddresses,
             orderValues,
-            fillTakerAmountInBaseUnits,
+            fillTakerAmount,
             shouldCheckTransfer,
             signedOrder.ecSignature.v,
             signedOrder.ecSignature.r,
@@ -203,39 +204,89 @@ export class ExchangeWrapper extends ContractWrapper {
         }
         this.exchangeLogEventObjs = [];
     }
-    private async validateFillOrderAsync(signedOrder: SignedOrder, fillTakerAmountInBaseUnits: BigNumber.BigNumber,
-                                         senderAddress: string) {
-        if (fillTakerAmountInBaseUnits.eq(0)) {
-            throw new Error(FillOrderValidationErrs.FILL_AMOUNT_IS_ZERO);
+    private async validateFillOrderAndThrowIfInvalidAsync(signedOrder: SignedOrder,
+                                                          fillTakerAmount: BigNumber.BigNumber,
+                                                          senderAddress: string): Promise<void> {
+        if (fillTakerAmount.eq(0)) {
+            throw new Error(ExchangeContractErrs.ORDER_REMAINING_FILL_AMOUNT_ZERO);
         }
         if (signedOrder.taker !== constants.NULL_ADDRESS && signedOrder.taker !== senderAddress) {
-            throw new Error(FillOrderValidationErrs.NOT_A_TAKER);
+            throw new Error(ExchangeContractErrs.TRANSACTION_SENDER_IS_NOT_FILL_ORDER_TAKER);
+        }
+        const currentUnixTimestampSec = Date.now() / 1000;
+        if (signedOrder.expirationUnixTimestampSec.lessThan(currentUnixTimestampSec)) {
+            throw new Error(ExchangeContractErrs.ORDER_FILL_EXPIRED);
         }
-        if (signedOrder.expirationUnixTimestampSec.lessThan(Date.now() / 1000)) {
-            throw new Error(FillOrderValidationErrs.EXPIRED);
+        const zrxTokenAddress = await this.getZRXTokenAddressAsync();
+        await this.validateFillOrderBalancesAndAllowancesAndThrowIfInvalidAsync(signedOrder, fillTakerAmount,
+                                                               senderAddress, zrxTokenAddress);
+
+        const wouldRoundingErrorOccur = await this.isRoundingErrorAsync(
+            signedOrder.takerTokenAmount, fillTakerAmount, signedOrder.makerTokenAmount,
+        );
+        if (wouldRoundingErrorOccur) {
+            throw new Error(ExchangeContractErrs.ORDER_FILL_ROUNDING_ERROR);
         }
+    }
+
+    /**
+     * This method does not currently validate the edge-case where the makerToken or takerToken is also the token used
+     * to pay fees  (ZRX). It is possible for them to have enough for fees and the transfer but not both.
+     * Handling the edge-cases that arise when this happens would require making sure that the user has sufficient
+     * funds to pay both the fees and the transfer amount. We decided to punt on this for now as the contracts
+     * will throw for these edge-cases.
+     * TODO: Throw errors before calling the smart contract for these edge-cases
+     * TODO: in order to minimize the callers gas costs.
+     */
+    private async validateFillOrderBalancesAndAllowancesAndThrowIfInvalidAsync(signedOrder: SignedOrder,
+                                                                               fillTakerAmount: BigNumber.BigNumber,
+                                                                               senderAddress: string,
+                                                                               zrxTokenAddress: string): Promise<void> {
+
         const makerBalance = await this.tokenWrapper.getBalanceAsync(signedOrder.makerTokenAddress,
-                                                                        signedOrder.maker);
+                                                                     signedOrder.maker);
         const takerBalance = await this.tokenWrapper.getBalanceAsync(signedOrder.takerTokenAddress, senderAddress);
         const makerAllowance = await this.tokenWrapper.getProxyAllowanceAsync(signedOrder.makerTokenAddress,
                                                                               signedOrder.maker);
         const takerAllowance = await this.tokenWrapper.getProxyAllowanceAsync(signedOrder.takerTokenAddress,
                                                                               senderAddress);
-        // How many taker tokens would you get for 1 maker token;
+
+        // exchangeRate is the price of one maker token denominated in taker tokens
         const exchangeRate = signedOrder.takerTokenAmount.div(signedOrder.makerTokenAmount);
-        const fillMakerAmountInBaseUnits = fillTakerAmountInBaseUnits.div(exchangeRate);
+        const fillMakerAmountInBaseUnits = fillTakerAmount.div(exchangeRate);
 
-        if (fillTakerAmountInBaseUnits.greaterThan(takerBalance)) {
-            throw new Error(FillOrderValidationErrs.NOT_ENOUGH_TAKER_BALANCE);
+        if (fillTakerAmount.greaterThan(takerBalance)) {
+            throw new Error(ExchangeContractErrs.INSUFFICIENT_TAKER_BALANCE);
         }
-        if (fillTakerAmountInBaseUnits.greaterThan(takerAllowance)) {
-            throw new Error(FillOrderValidationErrs.NOT_ENOUGH_TAKER_ALLOWANCE);
+        if (fillTakerAmount.greaterThan(takerAllowance)) {
+            throw new Error(ExchangeContractErrs.INSUFFICIENT_TAKER_ALLOWANCE);
         }
         if (fillMakerAmountInBaseUnits.greaterThan(makerBalance)) {
-            throw new Error(FillOrderValidationErrs.NOT_ENOUGH_MAKER_BALANCE);
+            throw new Error(ExchangeContractErrs.INSUFFICIENT_MAKER_BALANCE);
         }
         if (fillMakerAmountInBaseUnits.greaterThan(makerAllowance)) {
-            throw new Error(FillOrderValidationErrs.NOT_ENOUGH_MAKER_ALLOWANCE);
+            throw new Error(ExchangeContractErrs.INSUFFICIENT_MAKER_ALLOWANCE);
+        }
+
+        const makerFeeBalance = await this.tokenWrapper.getBalanceAsync(zrxTokenAddress,
+                                                                        signedOrder.maker);
+        const takerFeeBalance = await this.tokenWrapper.getBalanceAsync(zrxTokenAddress, senderAddress);
+        const makerFeeAllowance = await this.tokenWrapper.getProxyAllowanceAsync(zrxTokenAddress,
+                                                                                 signedOrder.maker);
+        const takerFeeAllowance = await this.tokenWrapper.getProxyAllowanceAsync(zrxTokenAddress,
+                                                                                 senderAddress);
+
+        if (signedOrder.takerFee.greaterThan(takerFeeBalance)) {
+            throw new Error(ExchangeContractErrs.INSUFFICIENT_TAKER_FEE_BALANCE);
+        }
+        if (signedOrder.takerFee.greaterThan(takerFeeAllowance)) {
+            throw new Error(ExchangeContractErrs.INSUFFICIENT_TAKER_FEE_ALLOWANCE);
+        }
+        if (signedOrder.makerFee.greaterThan(makerFeeBalance)) {
+            throw new Error(ExchangeContractErrs.INSUFFICIENT_MAKER_FEE_BALANCE);
+        }
+        if (signedOrder.makerFee.greaterThan(makerFeeAllowance)) {
+            throw new Error(ExchangeContractErrs.INSUFFICIENT_MAKER_FEE_ALLOWANCE);
         }
     }
     private throwErrorLogsAsErrors(logs: ContractEvent[]): void {
@@ -246,6 +297,18 @@ export class ExchangeWrapper extends ContractWrapper {
             throw new Error(errMessage);
         }
     }
+    private async isRoundingErrorAsync(takerTokenAmount: BigNumber.BigNumber,
+                                       fillTakerAmount: BigNumber.BigNumber,
+                                       makerTokenAmount: BigNumber.BigNumber): Promise<boolean> {
+        const exchangeInstance = await this.getExchangeContractAsync();
+        const senderAddress = await this.web3Wrapper.getSenderAddressOrThrowAsync();
+        const isRoundingError = await exchangeInstance.isRoundingError.call(
+            takerTokenAmount, fillTakerAmount, makerTokenAmount, {
+                from: senderAddress,
+            },
+        );
+        return isRoundingError;
+    }
     private async getExchangeContractAsync(): Promise<ExchangeContract> {
         if (!_.isUndefined(this.exchangeContractIfExists)) {
             return this.exchangeContractIfExists;
@@ -254,4 +317,8 @@ export class ExchangeWrapper extends ContractWrapper {
         this.exchangeContractIfExists = contractInstance as ExchangeContract;
         return this.exchangeContractIfExists;
     }
+    private async getZRXTokenAddressAsync(): Promise<string> {
+        const exchangeInstance = await this.getExchangeContractAsync();
+        return exchangeInstance.ZRX.call();
+    }
 }
diff --git a/src/types.ts b/src/types.ts
index c6ad68d3f..b5430a783 100644
--- a/src/types.ts
+++ b/src/types.ts
@@ -10,11 +10,12 @@ function strEnum(values: string[]): {[key: string]: string} {
 }
 
 export const ZeroExError = strEnum([
-  'CONTRACT_DOES_NOT_EXIST',
-  'UNHANDLED_ERROR',
-  'USER_HAS_NO_ASSOCIATED_ADDRESSES',
-  'INVALID_SIGNATURE',
-  'CONTRACT_NOT_DEPLOYED_ON_NETWORK',
+    'CONTRACT_DOES_NOT_EXIST',
+    'UNHANDLED_ERROR',
+    'USER_HAS_NO_ASSOCIATED_ADDRESSES',
+    'INVALID_SIGNATURE',
+    'CONTRACT_NOT_DEPLOYED_ON_NETWORK',
+    'ZRX_NOT_IN_TOKEN_REGISTRY',
 ]);
 export type ZeroExError = keyof typeof ZeroExError;
 
@@ -37,6 +38,10 @@ export interface ExchangeContract {
     getUnavailableValueT: {
         call: (orderHash: string) => BigNumber.BigNumber;
     };
+    isRoundingError: {
+        call: (takerTokenAmount: BigNumber.BigNumber, fillTakerAmount: BigNumber.BigNumber,
+               makerTokenAmount: BigNumber.BigNumber, txOpts: TxOpts) => Promise<boolean>;
+    };
     fill: {
         (orderAddresses: OrderAddresses, orderValues: OrderValues, fillAmount: BigNumber.BigNumber,
          shouldCheckTransfer: boolean, v: number, r: string, s: string, txOpts: TxOpts): ContractResponse;
@@ -65,6 +70,9 @@ export interface ExchangeContract {
     LogFill: CreateContractEvent;
     LogCancel: CreateContractEvent;
     LogError: CreateContractEvent;
+    ZRX: {
+        call: () => Promise<string>;
+    };
 }
 
 export interface TokenContract {
@@ -103,23 +111,22 @@ export enum ExchangeContractErrCodes {
 }
 
 export const ExchangeContractErrs = strEnum([
-    'ORDER_EXPIRED',
+    'ORDER_FILL_EXPIRED',
     'ORDER_REMAINING_FILL_AMOUNT_ZERO',
-    'ORDER_ROUNDING_ERROR',
-    'ORDER_BALANCE_ALLOWANCE_ERROR',
-]);
-export type ExchangeContractErrs = keyof typeof ExchangeContractErrs;
+    'ORDER_FILL_ROUNDING_ERROR',
+    'FILL_BALANCE_ALLOWANCE_ERROR',
+    'INSUFFICIENT_TAKER_BALANCE',
+    'INSUFFICIENT_TAKER_ALLOWANCE',
+    'INSUFFICIENT_MAKER_BALANCE',
+    'INSUFFICIENT_MAKER_ALLOWANCE',
+    'INSUFFICIENT_TAKER_FEE_BALANCE',
+    'INSUFFICIENT_TAKER_FEE_ALLOWANCE',
+    'INSUFFICIENT_MAKER_FEE_BALANCE',
+    'INSUFFICIENT_MAKER_FEE_ALLOWANCE',
+    'TRANSACTION_SENDER_IS_NOT_FILL_ORDER_TAKER',
 
-export const FillOrderValidationErrs = strEnum([
-    'FILL_AMOUNT_IS_ZERO',
-    'NOT_A_TAKER',
-    'EXPIRED',
-    'NOT_ENOUGH_TAKER_BALANCE',
-    'NOT_ENOUGH_TAKER_ALLOWANCE',
-    'NOT_ENOUGH_MAKER_BALANCE',
-    'NOT_ENOUGH_MAKER_ALLOWANCE',
 ]);
-export type FillOrderValidationErrs = keyof typeof FillOrderValidationErrs;
+export type ExchangeContractErrs = keyof typeof ExchangeContractErrs;
 
 export interface ContractResponse {
     logs: ContractEvent[];
diff --git a/src/utils/schema_validator.ts b/src/utils/schema_validator.ts
index db8a960ba..932ddf62a 100644
--- a/src/utils/schema_validator.ts
+++ b/src/utils/schema_validator.ts
@@ -6,7 +6,7 @@ import {tokenSchema} from '../schemas/token_schema';
 export class SchemaValidator {
     private validator: Validator;
     // In order to validate a complex JS object using jsonschema, we must replace any complex
-    // sub-types (e.g BigNumber) with a simpler string represenation. Since BigNumber and other
+    // sub-types (e.g BigNumber) with a simpler string representation. Since BigNumber and other
     // complex types implement the `toString` method, we can stringify the object and
     // then parse it. The resultant object can then be checked using jsonschema.
     public static convertToJSONSchemaCompatibleObject(obj: object): object {
diff --git a/test/exchange_wrapper_test.ts b/test/exchange_wrapper_test.ts
index cfb75789c..32b47f4f9 100644
--- a/test/exchange_wrapper_test.ts
+++ b/test/exchange_wrapper_test.ts
@@ -9,17 +9,17 @@ import promisify = require('es6-promisify');
 import {web3Factory} from './utils/web3_factory';
 import {ZeroEx} from '../src/0x.js';
 import {BlockchainLifecycle} from './utils/blockchain_lifecycle';
-import {orderFactory} from './utils/order_factory';
 import {
-    FillOrderValidationErrs,
     Token,
     SignedOrder,
     SubscriptionOpts,
     ExchangeEvents,
     ContractEvent,
     DoneCallback,
+    ExchangeContractErrs,
 } from '../src/types';
 import {FillScenarios} from './utils/fill_scenarios';
+import {TokenUtils} from './utils/token_utils';
 
 chai.use(dirtyChai);
 chai.use(ChaiBigNumber());
@@ -29,17 +29,21 @@ const blockchainLifecycle = new BlockchainLifecycle();
 const NON_EXISTENT_ORDER_HASH = '0x79370342234e7acd6bbeac335bd3bb1d368383294b64b8160a00f4060e4d3777';
 
 describe('ExchangeWrapper', () => {
+    let web3: Web3;
     let zeroEx: ZeroEx;
     let userAddresses: string[];
-    let web3: Web3;
+    let tokenUtils: TokenUtils;
     let tokens: Token[];
     let fillScenarios: FillScenarios;
+    let zrxTokenAddress: string;
     before(async () => {
         web3 = web3Factory.create();
         zeroEx = new ZeroEx(web3);
         userAddresses = await promisify(web3.eth.getAccounts)();
         tokens = await zeroEx.tokenRegistry.getTokensAsync();
-        fillScenarios = new FillScenarios(zeroEx, userAddresses, tokens);
+        tokenUtils = new TokenUtils(tokens);
+        zrxTokenAddress = tokenUtils.getProtocolTokenOrThrow().address;
+        fillScenarios = new FillScenarios(zeroEx, userAddresses, tokens, zrxTokenAddress);
     });
     beforeEach(async () => {
         await blockchainLifecycle.startAsync();
@@ -120,14 +124,16 @@ describe('ExchangeWrapper', () => {
     describe('#fillOrderAsync', () => {
         let makerTokenAddress: string;
         let takerTokenAddress: string;
-        let coinBase: string;
+        let coinbase: string;
         let makerAddress: string;
         let takerAddress: string;
-        const fillTakerAmountInBaseUnits = new BigNumber(5);
+        let feeRecipient: string;
+        const fillTakerAmount = new BigNumber(5);
         const shouldCheckTransfer = false;
-        before('fetch tokens', async () => {
-            [coinBase, makerAddress, takerAddress] = userAddresses;
-            const [makerToken, takerToken] = tokens;
+        before(async () => {
+            [coinbase, makerAddress, takerAddress, feeRecipient] = userAddresses;
+            tokens = await zeroEx.tokenRegistry.getTokensAsync();
+            const [makerToken, takerToken] = tokenUtils.getNonProtocolTokens();
             makerTokenAddress = makerToken.address;
             takerTokenAddress = takerToken.address;
         });
@@ -137,92 +143,149 @@ describe('ExchangeWrapper', () => {
         describe('failed fills', () => {
             it('should throw when the fill amount is zero', async () => {
                 const fillableAmount = new BigNumber(5);
-                const signedOrder = await fillScenarios.createAFillableSignedOrderAsync(
+                const signedOrder = await fillScenarios.createFillableSignedOrderAsync(
                     makerTokenAddress, takerTokenAddress, makerAddress, takerAddress, fillableAmount,
                 );
                 const zeroFillAmount = new BigNumber(0);
                 zeroEx.setTransactionSenderAccount(takerAddress);
                 return expect(zeroEx.exchange.fillOrderAsync(
                     signedOrder, zeroFillAmount, shouldCheckTransfer,
-                )).to.be.rejectedWith(FillOrderValidationErrs.FILL_AMOUNT_IS_ZERO);
+                )).to.be.rejectedWith(ExchangeContractErrs.ORDER_REMAINING_FILL_AMOUNT_ZERO);
             });
             it('should throw when sender is not a taker', async () => {
                 const fillableAmount = new BigNumber(5);
-                const signedOrder = await fillScenarios.createAFillableSignedOrderAsync(
+                const signedOrder = await fillScenarios.createFillableSignedOrderAsync(
                     makerTokenAddress, takerTokenAddress, makerAddress, takerAddress, fillableAmount,
                 );
                 return expect(zeroEx.exchange.fillOrderAsync(
-                    signedOrder, fillTakerAmountInBaseUnits, shouldCheckTransfer,
-                )).to.be.rejectedWith(FillOrderValidationErrs.NOT_A_TAKER);
+                    signedOrder, fillTakerAmount, shouldCheckTransfer,
+                )).to.be.rejectedWith(ExchangeContractErrs.TRANSACTION_SENDER_IS_NOT_FILL_ORDER_TAKER);
             });
             it('should throw when order is expired', async () => {
                 const expirationInPast = new BigNumber(42);
                 const fillableAmount = new BigNumber(5);
-                const signedOrder = await fillScenarios.createAFillableSignedOrderAsync(
+                const signedOrder = await fillScenarios.createFillableSignedOrderAsync(
                     makerTokenAddress, takerTokenAddress, makerAddress, takerAddress, fillableAmount, expirationInPast,
                 );
                 zeroEx.setTransactionSenderAccount(takerAddress);
                 return expect(zeroEx.exchange.fillOrderAsync(
-                    signedOrder, fillTakerAmountInBaseUnits, shouldCheckTransfer,
-                )).to.be.rejectedWith(FillOrderValidationErrs.EXPIRED);
+                    signedOrder, fillTakerAmount, shouldCheckTransfer,
+                )).to.be.rejectedWith(ExchangeContractErrs.ORDER_FILL_EXPIRED);
             });
-            it('should throw when taker balance is less than fill amount', async () => {
+            describe('should throw when not enough balance or allowance to fulfill the order', () => {
                 const fillableAmount = new BigNumber(5);
-                const signedOrder = await fillScenarios.createAFillableSignedOrderAsync(
-                    makerTokenAddress, takerTokenAddress, makerAddress, takerAddress, fillableAmount,
-                );
-                zeroEx.setTransactionSenderAccount(takerAddress);
-                const moreThanTheBalance = new BigNumber(6);
-                return expect(zeroEx.exchange.fillOrderAsync(
-                    signedOrder, moreThanTheBalance, shouldCheckTransfer,
-                )).to.be.rejectedWith(FillOrderValidationErrs.NOT_ENOUGH_TAKER_BALANCE);
+                const balanceToSubtractFromMaker = new BigNumber(3);
+                const lackingAllowance = new BigNumber(3);
+                let signedOrder: SignedOrder;
+                beforeEach('create fillable signed order', async () => {
+                    signedOrder = await fillScenarios.createFillableSignedOrderAsync(
+                        makerTokenAddress, takerTokenAddress, makerAddress, takerAddress, fillableAmount,
+                    );
+                });
+                it('should throw when taker balance is less than fill amount', async () => {
+                    await zeroEx.token.transferAsync(
+                        takerTokenAddress, takerAddress, coinbase, balanceToSubtractFromMaker,
+                    );
+                    zeroEx.setTransactionSenderAccount(takerAddress);
+                    return expect(zeroEx.exchange.fillOrderAsync(
+                        signedOrder, fillTakerAmount, shouldCheckTransfer,
+                    )).to.be.rejectedWith(ExchangeContractErrs.INSUFFICIENT_TAKER_BALANCE);
+                });
+                it('should throw when taker allowance is less than fill amount', async () => {
+                    const newAllowanceWhichIsLessThanFillAmount = fillTakerAmount.minus(lackingAllowance);
+                    await zeroEx.token.setProxyAllowanceAsync(takerTokenAddress, takerAddress,
+                        newAllowanceWhichIsLessThanFillAmount);
+                    zeroEx.setTransactionSenderAccount(takerAddress);
+                    return expect(zeroEx.exchange.fillOrderAsync(
+                        signedOrder, fillTakerAmount, shouldCheckTransfer,
+                    )).to.be.rejectedWith(ExchangeContractErrs.INSUFFICIENT_TAKER_ALLOWANCE);
+                });
+                it('should throw when maker balance is less than maker fill amount', async () => {
+                    await zeroEx.token.transferAsync(
+                        makerTokenAddress, makerAddress, coinbase, balanceToSubtractFromMaker,
+                    );
+                    zeroEx.setTransactionSenderAccount(takerAddress);
+                    return expect(zeroEx.exchange.fillOrderAsync(
+                        signedOrder, fillTakerAmount, shouldCheckTransfer,
+                    )).to.be.rejectedWith(ExchangeContractErrs.INSUFFICIENT_MAKER_BALANCE);
+                });
+                it('should throw when maker allowance is less than maker fill amount', async () => {
+                    const newAllowanceWhichIsLessThanFillAmount = fillTakerAmount.minus(lackingAllowance);
+                    await zeroEx.token.setProxyAllowanceAsync(makerTokenAddress, makerAddress,
+                        newAllowanceWhichIsLessThanFillAmount);
+                    zeroEx.setTransactionSenderAccount(takerAddress);
+                    return expect(zeroEx.exchange.fillOrderAsync(
+                        signedOrder, fillTakerAmount, shouldCheckTransfer,
+                    )).to.be.rejectedWith(ExchangeContractErrs.INSUFFICIENT_MAKER_ALLOWANCE);
+                });
             });
-            it('should throw when taker allowance is less than fill amount', async () => {
-                const fillableAmount = new BigNumber(5);
-                const signedOrder = await fillScenarios.createAFillableSignedOrderAsync(
-                    makerTokenAddress, takerTokenAddress, makerAddress, takerAddress, fillableAmount,
+            it('should throw when there a rounding error would have occurred', async () => {
+                const makerAmount = new BigNumber(3);
+                const takerAmount = new BigNumber(5);
+                const signedOrder = await fillScenarios.createAsymmetricFillableSignedOrderAsync(
+                    makerTokenAddress, takerTokenAddress, makerAddress, takerAddress,
+                    makerAmount, takerAmount,
                 );
-                const newAllowanceWhichIsLessThanFillAmount = fillTakerAmountInBaseUnits.minus(1);
-                await zeroEx.token.setProxyAllowanceAsync(takerTokenAddress, takerAddress,
-                                                    newAllowanceWhichIsLessThanFillAmount);
+                const fillTakerAmountThatCausesRoundingError = new BigNumber(3);
                 zeroEx.setTransactionSenderAccount(takerAddress);
                 return expect(zeroEx.exchange.fillOrderAsync(
-                    signedOrder, fillTakerAmountInBaseUnits, shouldCheckTransfer,
-                )).to.be.rejectedWith(FillOrderValidationErrs.NOT_ENOUGH_TAKER_ALLOWANCE);
+                    signedOrder, fillTakerAmountThatCausesRoundingError, shouldCheckTransfer,
+                )).to.be.rejectedWith(ExchangeContractErrs.ORDER_FILL_ROUNDING_ERROR);
             });
-            it('should throw when maker balance is less than maker fill amount', async () => {
+            describe('should throw when not enough balance or allowance to pay fees', () => {
                 const fillableAmount = new BigNumber(5);
-                const signedOrder = await fillScenarios.createAFillableSignedOrderAsync(
-                    makerTokenAddress, takerTokenAddress, makerAddress, takerAddress, fillableAmount,
-                );
-                const lackingMakerBalance = new BigNumber(3);
-                await zeroEx.token.transferAsync(makerTokenAddress, makerAddress, coinBase, lackingMakerBalance);
-                zeroEx.setTransactionSenderAccount(takerAddress);
-                return expect(zeroEx.exchange.fillOrderAsync(
-                    signedOrder, fillTakerAmountInBaseUnits, shouldCheckTransfer,
-                )).to.be.rejectedWith(FillOrderValidationErrs.NOT_ENOUGH_MAKER_BALANCE);
-            });
-            it('should throw when maker allowance is less than maker fill amount', async () => {
-                const fillableAmount = new BigNumber(5);
-                const signedOrder = await fillScenarios.createAFillableSignedOrderAsync(
-                    makerTokenAddress, takerTokenAddress, makerAddress, takerAddress, fillableAmount,
-                );
-                const newAllowanceWhichIsLessThanFillAmount = fillTakerAmountInBaseUnits.minus(1);
-                await zeroEx.token.setProxyAllowanceAsync(makerTokenAddress, makerAddress,
-                    newAllowanceWhichIsLessThanFillAmount);
-                zeroEx.setTransactionSenderAccount(takerAddress);
-                return expect(zeroEx.exchange.fillOrderAsync(
-                    signedOrder, fillTakerAmountInBaseUnits, shouldCheckTransfer,
-                )).to.be.rejectedWith(FillOrderValidationErrs.NOT_ENOUGH_MAKER_ALLOWANCE);
+                const makerFee = new BigNumber(2);
+                const takerFee = new BigNumber(2);
+                let signedOrder: SignedOrder;
+                beforeEach('setup', async () => {
+                    signedOrder = await fillScenarios.createFillableSignedOrderWithFeesAsync(
+                        makerTokenAddress, takerTokenAddress, makerFee, takerFee,
+                        makerAddress, takerAddress, fillableAmount, feeRecipient,
+                    );
+                    zeroEx.setTransactionSenderAccount(takerAddress);
+                });
+                it('should throw when maker doesn\'t have enough balance to pay fees', async () => {
+                    const balanceToSubtractFromMaker = new BigNumber(1);
+                    await zeroEx.token.transferAsync(
+                        zrxTokenAddress, makerAddress, coinbase, balanceToSubtractFromMaker,
+                    );
+                    return expect(zeroEx.exchange.fillOrderAsync(
+                        signedOrder, fillTakerAmount, shouldCheckTransfer,
+                    )).to.be.rejectedWith(ExchangeContractErrs.INSUFFICIENT_MAKER_FEE_BALANCE);
+                });
+                it('should throw when maker doesn\'t have enough allowance to pay fees', async () => {
+                    const newAllowanceWhichIsLessThanFees = makerFee.minus(1);
+                    await zeroEx.token.setProxyAllowanceAsync(zrxTokenAddress, makerAddress,
+                        newAllowanceWhichIsLessThanFees);
+                    return expect(zeroEx.exchange.fillOrderAsync(
+                        signedOrder, fillTakerAmount, shouldCheckTransfer,
+                    )).to.be.rejectedWith(ExchangeContractErrs.INSUFFICIENT_MAKER_FEE_ALLOWANCE);
+                });
+                it('should throw when taker doesn\'t have enough balance to pay fees', async () => {
+                    const balanceToSubtractFromTaker = new BigNumber(1);
+                    await zeroEx.token.transferAsync(
+                        zrxTokenAddress, takerAddress, coinbase, balanceToSubtractFromTaker,
+                    );
+                    return expect(zeroEx.exchange.fillOrderAsync(
+                        signedOrder, fillTakerAmount, shouldCheckTransfer,
+                    )).to.be.rejectedWith(ExchangeContractErrs.INSUFFICIENT_TAKER_FEE_BALANCE);
+                });
+                it('should throw when taker doesn\'t have enough allowance to pay fees', async () => {
+                    const newAllowanceWhichIsLessThanFees = makerFee.minus(1);
+                    await zeroEx.token.setProxyAllowanceAsync(zrxTokenAddress, takerAddress,
+                        newAllowanceWhichIsLessThanFees);
+                    return expect(zeroEx.exchange.fillOrderAsync(
+                        signedOrder, fillTakerAmount, shouldCheckTransfer,
+                    )).to.be.rejectedWith(ExchangeContractErrs.INSUFFICIENT_TAKER_FEE_ALLOWANCE);
+                });
             });
         });
         describe('successful fills', () => {
-            it('should fill the valid order', async () => {
+            it('should fill a valid order', async () => {
                 const fillableAmount = new BigNumber(5);
-                const signedOrder = await fillScenarios.createAFillableSignedOrderAsync(
+                const signedOrder = await fillScenarios.createFillableSignedOrderAsync(
                     makerTokenAddress, takerTokenAddress, makerAddress, takerAddress, fillableAmount,
                 );
-
                 expect(await zeroEx.token.getBalanceAsync(makerTokenAddress, makerAddress))
                     .to.be.bignumber.equal(fillableAmount);
                 expect(await zeroEx.token.getBalanceAsync(takerTokenAddress, makerAddress))
@@ -232,19 +295,19 @@ describe('ExchangeWrapper', () => {
                 expect(await zeroEx.token.getBalanceAsync(takerTokenAddress, takerAddress))
                     .to.be.bignumber.equal(fillableAmount);
                 zeroEx.setTransactionSenderAccount(takerAddress);
-                await zeroEx.exchange.fillOrderAsync(signedOrder, fillTakerAmountInBaseUnits, shouldCheckTransfer);
+                await zeroEx.exchange.fillOrderAsync(signedOrder, fillTakerAmount, shouldCheckTransfer);
                 expect(await zeroEx.token.getBalanceAsync(makerTokenAddress, makerAddress))
-                    .to.be.bignumber.equal(fillableAmount.minus(fillTakerAmountInBaseUnits));
+                    .to.be.bignumber.equal(fillableAmount.minus(fillTakerAmount));
                 expect(await zeroEx.token.getBalanceAsync(takerTokenAddress, makerAddress))
-                    .to.be.bignumber.equal(fillTakerAmountInBaseUnits);
+                    .to.be.bignumber.equal(fillTakerAmount);
                 expect(await zeroEx.token.getBalanceAsync(makerTokenAddress, takerAddress))
-                    .to.be.bignumber.equal(fillTakerAmountInBaseUnits);
+                    .to.be.bignumber.equal(fillTakerAmount);
                 expect(await zeroEx.token.getBalanceAsync(takerTokenAddress, takerAddress))
-                    .to.be.bignumber.equal(fillableAmount.minus(fillTakerAmountInBaseUnits));
+                    .to.be.bignumber.equal(fillableAmount.minus(fillTakerAmount));
             });
             it('should partially fill the valid order', async () => {
                 const fillableAmount = new BigNumber(5);
-                const signedOrder = await fillScenarios.createAFillableSignedOrderAsync(
+                const signedOrder = await fillScenarios.createFillableSignedOrderAsync(
                     makerTokenAddress, takerTokenAddress, makerAddress, takerAddress, fillableAmount,
                 );
                 const partialFillAmount = new BigNumber(3);
@@ -259,6 +322,19 @@ describe('ExchangeWrapper', () => {
                 expect(await zeroEx.token.getBalanceAsync(takerTokenAddress, takerAddress))
                     .to.be.bignumber.equal(fillableAmount.minus(partialFillAmount));
             });
+            it('should fill the valid orders with fees', async () => {
+                const fillableAmount = new BigNumber(5);
+                const makerFee = new BigNumber(1);
+                const takerFee = new BigNumber(2);
+                const signedOrder = await fillScenarios.createFillableSignedOrderWithFeesAsync(
+                    makerTokenAddress, takerTokenAddress, makerFee, takerFee,
+                    makerAddress, takerAddress, fillableAmount, feeRecipient,
+                );
+                zeroEx.setTransactionSenderAccount(takerAddress);
+                await zeroEx.exchange.fillOrderAsync(signedOrder, fillTakerAmount, shouldCheckTransfer);
+                expect(await zeroEx.token.getBalanceAsync(zrxTokenAddress, feeRecipient))
+                    .to.be.bignumber.equal(makerFee.plus(takerFee));
+            });
         });
     });
     describe('tests that require partially filled order', () => {
@@ -332,20 +408,20 @@ describe('ExchangeWrapper', () => {
         const shouldCheckTransfer = false;
         let makerTokenAddress: string;
         let takerTokenAddress: string;
-        let coinBase: string;
+        let coinbase: string;
         let takerAddress: string;
         let makerAddress: string;
         let fillableAmount: BigNumber.BigNumber;
         let signedOrder: SignedOrder;
         before(() => {
-            [coinBase, makerAddress, takerAddress] = userAddresses;
+            [coinbase, makerAddress, takerAddress] = userAddresses;
             const [makerToken, takerToken] = tokens;
             makerTokenAddress = makerToken.address;
             takerTokenAddress = takerToken.address;
         });
         beforeEach(async () => {
             fillableAmount = new BigNumber(5);
-            signedOrder = await fillScenarios.createAFillableSignedOrderAsync(
+            signedOrder = await fillScenarios.createFillableSignedOrderAsync(
                 makerTokenAddress, takerTokenAddress, makerAddress, takerAddress, fillableAmount,
             );
         });
diff --git a/test/utils/fill_scenarios.ts b/test/utils/fill_scenarios.ts
index 17c2dbeba..ea5eb77eb 100644
--- a/test/utils/fill_scenarios.ts
+++ b/test/utils/fill_scenarios.ts
@@ -2,35 +2,54 @@ import * as BigNumber from 'bignumber.js';
 import {ZeroEx} from '../../src/0x.js';
 import {Token, SignedOrder} from '../../src/types';
 import {orderFactory} from '../utils/order_factory';
+import {constants} from './constants';
 
 export class FillScenarios {
     private zeroEx: ZeroEx;
     private userAddresses: string[];
     private tokens: Token[];
-    private coinBase: string;
-    constructor(zeroEx: ZeroEx, userAddresses: string[], tokens: Token[]) {
+    private coinbase: string;
+    private zrxTokenAddress: string;
+    constructor(zeroEx: ZeroEx, userAddresses: string[], tokens: Token[], zrxTokenAddress: string) {
         this.zeroEx = zeroEx;
         this.userAddresses = userAddresses;
         this.tokens = tokens;
-        this.coinBase = userAddresses[0];
+        this.coinbase = userAddresses[0];
+        this.zrxTokenAddress = zrxTokenAddress;
     }
-    public async createAFillableSignedOrderAsync(makerTokenAddress: string, takerTokenAddress: string,
-                                                 makerAddress: string, takerAddress: string,
-                                                 fillableAmount: BigNumber.BigNumber,
-                                                 expirationUnixTimestampSec?: BigNumber.BigNumber):
+    public async createFillableSignedOrderAsync(makerTokenAddress: string, takerTokenAddress: string,
+                                                makerAddress: string, takerAddress: string,
+                                                fillableAmount: BigNumber.BigNumber,
+                                                expirationUnixTimestampSec?: BigNumber.BigNumber):
                                            Promise<SignedOrder> {
-        await this.zeroEx.token.transferAsync(makerTokenAddress, this.coinBase, makerAddress, fillableAmount);
-        await this.zeroEx.token.setProxyAllowanceAsync(makerTokenAddress, makerAddress, fillableAmount);
-        await this.zeroEx.token.transferAsync(takerTokenAddress, this.coinBase, takerAddress, fillableAmount);
-        await this.zeroEx.token.setProxyAllowanceAsync(takerTokenAddress, takerAddress, fillableAmount);
-
-        const transactionSenderAccount = await this.zeroEx.getTransactionSenderAccountIfExistsAsync();
-        this.zeroEx.setTransactionSenderAccount(makerAddress);
-        const signedOrder = await orderFactory.createSignedOrderAsync(this.zeroEx, makerAddress,
-            takerAddress, fillableAmount, makerTokenAddress, fillableAmount, takerTokenAddress,
-            expirationUnixTimestampSec);
-        this.zeroEx.setTransactionSenderAccount(transactionSenderAccount as string);
-        return signedOrder;
+        return this.createAsymmetricFillableSignedOrderAsync(
+            makerTokenAddress, takerTokenAddress, makerAddress, takerAddress,
+            fillableAmount, fillableAmount, expirationUnixTimestampSec,
+        );
+    }
+    public async createFillableSignedOrderWithFeesAsync(
+        makerTokenAddress: string, takerTokenAddress: string,
+        makerFee: BigNumber.BigNumber, takerFee: BigNumber.BigNumber,
+        makerAddress: string, takerAddress: string,
+        fillableAmount: BigNumber.BigNumber,
+        feeRecepient: string, expirationUnixTimestampSec?: BigNumber.BigNumber,
+    ): Promise<SignedOrder> {
+        return this.createAsymmetricFillableSignedOrderWithFeesAsync(
+            makerTokenAddress, takerTokenAddress, makerFee, takerFee, makerAddress, takerAddress,
+            fillableAmount, fillableAmount, feeRecepient, expirationUnixTimestampSec,
+        );
+    }
+    public async createAsymmetricFillableSignedOrderAsync(
+        makerTokenAddress: string, takerTokenAddress: string, makerAddress: string, takerAddress: string,
+        makerFillableAmount: BigNumber.BigNumber, takerFillableAmount: BigNumber.BigNumber,
+        expirationUnixTimestampSec?: BigNumber.BigNumber): Promise<SignedOrder> {
+        const makerFee = new BigNumber(0);
+        const takerFee = new BigNumber(0);
+        const feeRecepient = constants.NULL_ADDRESS;
+        return this.createAsymmetricFillableSignedOrderWithFeesAsync(
+            makerTokenAddress, takerTokenAddress, makerFee, takerFee, makerAddress, takerAddress,
+            makerFillableAmount, takerFillableAmount, feeRecepient, expirationUnixTimestampSec,
+        );
     }
     public async createPartiallyFilledSignedOrderAsync(makerTokenAddress: string, takerTokenAddress: string,
                                                        takerAddress: string, fillableAmount: BigNumber.BigNumber,
@@ -41,8 +60,10 @@ export class FillScenarios {
         await this.zeroEx.token.transferAsync(takerTokenAddress, makerAddress, takerAddress, fillableAmount);
         await this.zeroEx.token.setProxyAllowanceAsync(takerTokenAddress, takerAddress, fillableAmount);
 
-        const signedOrder = await orderFactory.createSignedOrderAsync(this.zeroEx, makerAddress,
-         takerAddress, fillableAmount, makerTokenAddress, fillableAmount, takerTokenAddress);
+        const signedOrder = await this.createAsymmetricFillableSignedOrderAsync(
+             makerTokenAddress, takerTokenAddress, makerAddress, takerAddress,
+             fillableAmount, fillableAmount,
+         );
 
         this.zeroEx.setTransactionSenderAccount(takerAddress);
         const shouldCheckTransfer = false;
@@ -52,4 +73,34 @@ export class FillScenarios {
         this.zeroEx.setTransactionSenderAccount(prevSenderAccount as string);
         return signedOrder;
     }
+    private async createAsymmetricFillableSignedOrderWithFeesAsync(
+        makerTokenAddress: string, takerTokenAddress: string,
+        makerFee: BigNumber.BigNumber, takerFee: BigNumber.BigNumber,
+        makerAddress: string, takerAddress: string,
+        makerFillableAmount: BigNumber.BigNumber, takerFillableAmount: BigNumber.BigNumber,
+        feeRecepient: string, expirationUnixTimestampSec?: BigNumber.BigNumber): Promise<SignedOrder> {
+        await this.zeroEx.token.transferAsync(makerTokenAddress, this.coinbase, makerAddress, makerFillableAmount);
+        await this.zeroEx.token.setProxyAllowanceAsync(makerTokenAddress, makerAddress, makerFillableAmount);
+        await this.zeroEx.token.transferAsync(takerTokenAddress, this.coinbase, takerAddress, takerFillableAmount);
+        await this.zeroEx.token.setProxyAllowanceAsync(takerTokenAddress, takerAddress, takerFillableAmount);
+
+        if (!makerFee.isZero()) {
+            await this.zeroEx.token.transferAsync(this.zrxTokenAddress, this.coinbase, makerAddress, makerFee);
+            await this.zeroEx.token.setProxyAllowanceAsync(this.zrxTokenAddress, makerAddress, makerFee);
+        }
+        if (!takerFee.isZero()) {
+            await this.zeroEx.token.transferAsync(this.zrxTokenAddress, this.coinbase, takerAddress, takerFee);
+            await this.zeroEx.token.setProxyAllowanceAsync(this.zrxTokenAddress, takerAddress, takerFee);
+        }
+
+        const prevTransactionSenderAccount = await this.zeroEx.getTransactionSenderAccountIfExistsAsync();
+        this.zeroEx.setTransactionSenderAccount(makerAddress);
+        const signedOrder = await orderFactory.createSignedOrderAsync(this.zeroEx,
+            makerAddress, takerAddress, makerFee, takerFee,
+            makerFillableAmount, makerTokenAddress, takerFillableAmount, takerTokenAddress,
+            feeRecepient, expirationUnixTimestampSec);
+        // We re-set the transactionSender to avoid introducing side-effects
+        this.zeroEx.setTransactionSenderAccount(prevTransactionSenderAccount as string);
+        return signedOrder;
+    }
 }
diff --git a/test/utils/order_factory.ts b/test/utils/order_factory.ts
index 0f370ed34..373dbddc6 100644
--- a/test/utils/order_factory.ts
+++ b/test/utils/order_factory.ts
@@ -10,10 +10,13 @@ export const orderFactory = {
         zeroEx: ZeroEx,
         maker: string,
         taker: string,
-        makerTokenAmount: BigNumber.BigNumber|number,
+        makerFee: BigNumber.BigNumber,
+        takerFee: BigNumber.BigNumber,
+        makerTokenAmount: BigNumber.BigNumber,
         makerTokenAddress: string,
-        takerTokenAmount: BigNumber.BigNumber|number,
+        takerTokenAmount: BigNumber.BigNumber,
         takerTokenAddress: string,
+        feeRecipient: string,
         expirationUnixTimestampSec?: BigNumber.BigNumber): Promise<SignedOrder> {
         const defaultExpirationUnixTimestampSec = new BigNumber(2524604400); // Close to infinite
         expirationUnixTimestampSec = _.isUndefined(expirationUnixTimestampSec) ?
@@ -22,14 +25,14 @@ export const orderFactory = {
         const order = {
             maker,
             taker,
-            makerFee: new BigNumber(0),
-            takerFee: new BigNumber(0),
-            makerTokenAmount: _.isNumber(makerTokenAmount) ? new BigNumber(makerTokenAmount) : makerTokenAmount,
-            takerTokenAmount: _.isNumber(takerTokenAmount) ? new BigNumber(takerTokenAmount) : takerTokenAmount,
+            makerFee,
+            takerFee,
+            makerTokenAmount,
+            takerTokenAmount,
             makerTokenAddress,
             takerTokenAddress,
             salt: ZeroEx.generatePseudoRandomSalt(),
-            feeRecipient: constants.NULL_ADDRESS,
+            feeRecipient,
             expirationUnixTimestampSec,
         };
         const orderHash = await zeroEx.getOrderHashHexAsync(order);
diff --git a/test/utils/token_utils.ts b/test/utils/token_utils.ts
new file mode 100644
index 000000000..14788b299
--- /dev/null
+++ b/test/utils/token_utils.ts
@@ -0,0 +1,24 @@
+import * as _ from 'lodash';
+import {Token, ZeroExError} from '../../src/types';
+
+const PROTOCOL_TOKEN_SYMBOL = 'ZRX';
+
+export class TokenUtils {
+    private tokens: Token[];
+    constructor(tokens: Token[]) {
+        this.tokens = tokens;
+    }
+    public getProtocolTokenOrThrow(): Token {
+        const zrxToken = _.find(this.tokens, {symbol: PROTOCOL_TOKEN_SYMBOL});
+        if (_.isUndefined(zrxToken)) {
+            throw new Error(ZeroExError.ZRX_NOT_IN_TOKEN_REGISTRY);
+        }
+        return zrxToken;
+    }
+    public getNonProtocolTokens(): Token[] {
+        const nonProtocolTokens = _.filter(this.tokens, token => {
+            return token.symbol !== PROTOCOL_TOKEN_SYMBOL;
+        });
+        return nonProtocolTokens;
+    }
+}