Merge branch 'sol-cov-fixes' of github.com:0xProject/0x-monorepo into sol-cov-fixes

* 'sol-cov-fixes' of github.com:0xProject/0x-monorepo: (49 commits)
  Add @return comments
  Import marshaller directly
  Update comment about ethers checksummed address behavior
  Add packages/coverage/.gitkeep file
  Update CI config and package.json to run @0xproject/utils tests on CI
  Update remaining CHANGELOG.json files
  Change amir picture
  Update CHANGELOG.json for contract-wrappers
  Update ethers typings for TypeScript 2.9.2
  Update CHANGELOG.json for base-contract
  Move some ethers-related types to typescript-typings/ethers
  Apply prettier
  Add strictArgumentEncodingCheck to BaseContract and use it in contract templates
  fix(monorepo-scripts): Fix typo in git tag command
  feat(monorepo-scripts): Add confirmation prompt before publishing
  fix comments and styling for MixinSignatureValidator
  Update TypeScript to version 2.9.2
  Use asm for hashEIP712Message, increment free memory pointer after asm hashing functions
  Fix comments, styling, and optimize hashOrder
  Remove assertion comments
  ...

10 files changed, 546 insertions, 25 deletions

diff --git a/packages/order-utils/CHANGELOG.json b/packages/order-utils/CHANGELOG.json
index a399f5ea1..fa82976ad 100644
--- a/packages/order-utils/CHANGELOG.json
+++ b/packages/order-utils/CHANGELOG.json
@@ -1,5 +1,22 @@
 [
     {
+        "version": "1.0.1-rc.3",
+        "changes": [
+            {
+                "note":
+                    "Added a synchronous `createOrder` method in `orderFactory`, updated public interfaces to support some optional parameters",
+                "pr": 936
+            },
+            {
+                "note": "Added marketUtils",
+                "pr": 937
+            },
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
+    {
         "version": "1.0.1-rc.2",
         "changes": [
             {
diff --git a/packages/order-utils/package.json b/packages/order-utils/package.json
index cab917a82..7880b9352 100644
--- a/packages/order-utils/package.json
+++ b/packages/order-utils/package.json
@@ -70,7 +70,7 @@
         "sinon": "^4.0.0",
         "tslint": "5.11.0",
         "typedoc": "0xProject/typedoc",
-        "typescript": "2.7.1"
+        "typescript": "2.9.2"
     },
     "dependencies": {
         "@0xproject/assert": "^1.0.4",
diff --git a/packages/order-utils/src/constants.ts b/packages/order-utils/src/constants.ts
index bb7482184..c23578c20 100644
--- a/packages/order-utils/src/constants.ts
+++ b/packages/order-utils/src/constants.ts
@@ -2,6 +2,7 @@ import { BigNumber } from '@0xproject/utils';
 
 export const constants = {
     NULL_ADDRESS: '0x0000000000000000000000000000000000000000',
+    NULL_BYTES: '0x',
     // tslint:disable-next-line:custom-no-magic-numbers
     UNLIMITED_ALLOWANCE_IN_BASE_UNITS: new BigNumber(2).pow(256).minus(1),
     TESTRPC_NETWORK_ID: 50,
@@ -10,4 +11,6 @@ export const constants = {
     ERC721_ASSET_DATA_MINIMUM_BYTE_LENGTH: 53,
     SELECTOR_LENGTH: 4,
     BASE_16: 16,
+    INFINITE_TIMESTAMP_SEC: new BigNumber(2524604400), // Close to infinite
+    ZERO_AMOUNT: new BigNumber(0),
 };
diff --git a/packages/order-utils/src/index.ts b/packages/order-utils/src/index.ts
index 76be63bb8..858f500c6 100644
--- a/packages/order-utils/src/index.ts
+++ b/packages/order-utils/src/index.ts
@@ -13,7 +13,15 @@ export { orderFactory } from './order_factory';
 export { constants } from './constants';
 export { crypto } from './crypto';
 export { generatePseudoRandomSalt } from './salt';
-export { OrderError, MessagePrefixType, MessagePrefixOpts, EIP712Parameter, EIP712Schema, EIP712Types } from './types';
+export {
+    CreateOrderOpts,
+    OrderError,
+    MessagePrefixType,
+    MessagePrefixOpts,
+    EIP712Parameter,
+    EIP712Schema,
+    EIP712Types,
+} from './types';
 export { AbstractBalanceAndProxyAllowanceFetcher } from './abstract/abstract_balance_and_proxy_allowance_fetcher';
 export { AbstractOrderFilledCancelledFetcher } from './abstract/abstract_order_filled_cancelled_fetcher';
 export { BalanceAndProxyAllowanceLazyStore } from './store/balance_and_proxy_allowance_lazy_store';
@@ -24,3 +32,4 @@ export { assetDataUtils } from './asset_data_utils';
 export { EIP712Utils } from './eip712_utils';
 export { OrderValidationUtils } from './order_validation_utils';
 export { ExchangeTransferSimulator } from './exchange_transfer_simulator';
+export { marketUtils } from './market_utils';
diff --git a/packages/order-utils/src/market_utils.ts b/packages/order-utils/src/market_utils.ts
new file mode 100644
index 000000000..681059ddf
--- /dev/null
+++ b/packages/order-utils/src/market_utils.ts
@@ -0,0 +1,133 @@
+import { schemas } from '@0xproject/json-schemas';
+import { SignedOrder } from '@0xproject/types';
+import { BigNumber } from '@0xproject/utils';
+import * as _ from 'lodash';
+
+import { assert } from './assert';
+import { constants } from './constants';
+
+export const marketUtils = {
+    /**
+     * Takes an array of orders and returns a subset of those orders that has enough makerAssetAmount (taking into account on-chain balances,
+     * allowances, and partial fills) in order to fill the input makerAssetFillAmount plus slippageBufferAmount. Iterates from first order to last.
+     * Sort the input by ascending rate in order to get the subset of orders that will cost the least ETH.
+     * @param   signedOrders                        An array of objects that conform to the SignedOrder interface. All orders should specify the same makerAsset.
+     *                                              All orders should specify WETH as the takerAsset.
+     * @param   remainingFillableMakerAssetAmounts  An array of BigNumbers corresponding to the signedOrders parameter.
+     *                                              You can use OrderStateUtils @0xproject/order-utils to perform blockchain lookups
+     *                                              for these values.
+     * @param   makerAssetFillAmount                The amount of makerAsset desired to be filled.
+     * @param   slippageBufferAmount                An additional amount of makerAsset to be covered by the result in case of trade collisions or partial fills.
+     * @return  Resulting orders and remaining fill amount that could not be covered by the input.
+     */
+    findOrdersThatCoverMakerAssetFillAmount(
+        signedOrders: SignedOrder[],
+        remainingFillableMakerAssetAmounts: BigNumber[],
+        makerAssetFillAmount: BigNumber,
+        slippageBufferAmount: BigNumber = constants.ZERO_AMOUNT,
+    ): { resultOrders: SignedOrder[]; remainingFillAmount: BigNumber } {
+        assert.doesConformToSchema('signedOrders', signedOrders, schemas.signedOrdersSchema);
+        _.forEach(remainingFillableMakerAssetAmounts, (amount, index) =>
+            assert.isValidBaseUnitAmount(`remainingFillableMakerAssetAmount[${index}]`, amount),
+        );
+        assert.isValidBaseUnitAmount('makerAssetFillAmount', makerAssetFillAmount);
+        assert.isValidBaseUnitAmount('slippageBufferAmount', slippageBufferAmount);
+        assert.assert(
+            signedOrders.length === remainingFillableMakerAssetAmounts.length,
+            'Expected signedOrders.length to equal remainingFillableMakerAssetAmounts.length',
+        );
+        // calculate total amount of makerAsset needed to be filled
+        const totalFillAmount = makerAssetFillAmount.plus(slippageBufferAmount);
+        // iterate through the signedOrders input from left to right until we have enough makerAsset to fill totalFillAmount
+        const result = _.reduce(
+            signedOrders,
+            ({ resultOrders, remainingFillAmount }, order, index) => {
+                if (remainingFillAmount.lessThanOrEqualTo(constants.ZERO_AMOUNT)) {
+                    return { resultOrders, remainingFillAmount: constants.ZERO_AMOUNT };
+                } else {
+                    const makerAssetAmountAvailable = remainingFillableMakerAssetAmounts[index];
+                    // if there is no makerAssetAmountAvailable do not append order to resultOrders
+                    // if we have exceeded the total amount we want to fill set remainingFillAmount to 0
+                    return {
+                        resultOrders: makerAssetAmountAvailable.gt(constants.ZERO_AMOUNT)
+                            ? _.concat(resultOrders, order)
+                            : resultOrders,
+                        remainingFillAmount: BigNumber.max(
+                            constants.ZERO_AMOUNT,
+                            remainingFillAmount.minus(makerAssetAmountAvailable),
+                        ),
+                    };
+                }
+            },
+            { resultOrders: [] as SignedOrder[], remainingFillAmount: totalFillAmount },
+        );
+        return result;
+    },
+    /**
+     * Takes an array of orders and an array of feeOrders. Returns a subset of the feeOrders that has enough ZRX (taking into account
+     * on-chain balances, allowances, and partial fills) in order to fill the takerFees required by signedOrders plus a
+     * slippageBufferAmount. Iterates from first feeOrder to last. Sort the feeOrders by ascending rate in order to get the subset of
+     * feeOrders that will cost the least ETH.
+     * @param   signedOrders                        An array of objects that conform to the SignedOrder interface. All orders should specify ZRX as
+     *                                              the makerAsset and WETH as the takerAsset.
+     * @param   remainingFillableMakerAssetAmounts  An array of BigNumbers corresponding to the signedOrders parameter.
+     *                                              You can use OrderStateUtils @0xproject/order-utils to perform blockchain lookups
+     *                                              for these values.
+     * @param   signedFeeOrders                     An array of objects that conform to the SignedOrder interface. All orders should specify ZRX as
+     *                                              the makerAsset and WETH as the takerAsset.
+     * @param   remainingFillableFeeAmounts         An array of BigNumbers corresponding to the signedFeeOrders parameter.
+     *                                              You can use OrderStateUtils @0xproject/order-utils to perform blockchain lookups
+     *                                              for these values.
+     * @param   slippageBufferAmount                An additional amount of fee to be covered by the result in case of trade collisions or partial fills.
+     * @return  Resulting orders and remaining fee amount that could not be covered by the input.
+     */
+    findFeeOrdersThatCoverFeesForTargetOrders(
+        signedOrders: SignedOrder[],
+        remainingFillableMakerAssetAmounts: BigNumber[],
+        signedFeeOrders: SignedOrder[],
+        remainingFillableFeeAmounts: BigNumber[],
+        slippageBufferAmount: BigNumber = constants.ZERO_AMOUNT,
+    ): { resultOrders: SignedOrder[]; remainingFeeAmount: BigNumber } {
+        assert.doesConformToSchema('signedOrders', signedOrders, schemas.signedOrdersSchema);
+        _.forEach(remainingFillableMakerAssetAmounts, (amount, index) =>
+            assert.isValidBaseUnitAmount(`remainingFillableMakerAssetAmount[${index}]`, amount),
+        );
+        assert.doesConformToSchema('signedFeeOrders', signedFeeOrders, schemas.signedOrdersSchema);
+        _.forEach(remainingFillableFeeAmounts, (amount, index) =>
+            assert.isValidBaseUnitAmount(`remainingFillableFeeAmounts[${index}]`, amount),
+        );
+        assert.isValidBaseUnitAmount('slippageBufferAmount', slippageBufferAmount);
+        assert.assert(
+            signedOrders.length === remainingFillableMakerAssetAmounts.length,
+            'Expected signedOrders.length to equal remainingFillableMakerAssetAmounts.length',
+        );
+        assert.assert(
+            signedOrders.length === remainingFillableMakerAssetAmounts.length,
+            'Expected signedFeeOrders.length to equal remainingFillableFeeAmounts.length',
+        );
+        // calculate total amount of ZRX needed to fill signedOrders
+        const totalFeeAmount = _.reduce(
+            signedOrders,
+            (accFees, order, index) => {
+                const makerAssetAmountAvailable = remainingFillableMakerAssetAmounts[index];
+                const feeToFillMakerAssetAmountAvailable = makerAssetAmountAvailable
+                    .mul(order.takerFee)
+                    .div(order.makerAssetAmount);
+                return accFees.plus(feeToFillMakerAssetAmountAvailable);
+            },
+            constants.ZERO_AMOUNT,
+        );
+        const { resultOrders, remainingFillAmount } = marketUtils.findOrdersThatCoverMakerAssetFillAmount(
+            signedFeeOrders,
+            remainingFillableFeeAmounts,
+            totalFeeAmount,
+            slippageBufferAmount,
+        );
+        return {
+            resultOrders,
+            remainingFeeAmount: remainingFillAmount,
+        };
+        // TODO: add more orders here to cover rounding
+        // https://github.com/0xProject/0x-protocol-specification/blob/master/v2/forwarding-contract-specification.md#over-buying-zrx
+    },
+};
diff --git a/packages/order-utils/src/order_factory.ts b/packages/order-utils/src/order_factory.ts
index 803cb82b1..14727fd97 100644
--- a/packages/order-utils/src/order_factory.ts
+++ b/packages/order-utils/src/order_factory.ts
@@ -1,49 +1,63 @@
-import { ECSignature, SignedOrder } from '@0xproject/types';
+import { ECSignature, Order, SignedOrder } from '@0xproject/types';
 import { BigNumber } from '@0xproject/utils';
 import { Provider } from 'ethereum-types';
 import * as ethUtil from 'ethereumjs-util';
 import * as _ from 'lodash';
 
+import { constants } from './constants';
 import { orderHashUtils } from './order_hash';
 import { generatePseudoRandomSalt } from './salt';
 import { ecSignOrderHashAsync } from './signature_utils';
-import { MessagePrefixType } from './types';
+import { CreateOrderOpts, MessagePrefixType } from './types';
 
 export const orderFactory = {
-    async createSignedOrderAsync(
-        provider: Provider,
+    createOrder(
         makerAddress: string,
-        takerAddress: string,
-        senderAddress: string,
-        makerFee: BigNumber,
-        takerFee: BigNumber,
         makerAssetAmount: BigNumber,
         makerAssetData: string,
         takerAssetAmount: BigNumber,
         takerAssetData: string,
         exchangeAddress: string,
-        feeRecipientAddress: string,
-        expirationTimeSecondsIfExists?: BigNumber,
-    ): Promise<SignedOrder> {
-        const defaultExpirationUnixTimestampSec = new BigNumber(2524604400); // Close to infinite
-        const expirationTimeSeconds = _.isUndefined(expirationTimeSecondsIfExists)
-            ? defaultExpirationUnixTimestampSec
-            : expirationTimeSecondsIfExists;
+        createOrderOpts: CreateOrderOpts = generateDefaultCreateOrderOpts(),
+    ): Order {
+        const defaultCreateOrderOpts = generateDefaultCreateOrderOpts();
         const order = {
             makerAddress,
-            takerAddress,
-            senderAddress,
-            makerFee,
-            takerFee,
             makerAssetAmount,
             takerAssetAmount,
             makerAssetData,
             takerAssetData,
-            salt: generatePseudoRandomSalt(),
             exchangeAddress,
-            feeRecipientAddress,
-            expirationTimeSeconds,
+            takerAddress: createOrderOpts.takerAddress || defaultCreateOrderOpts.takerAddress,
+            senderAddress: createOrderOpts.senderAddress || defaultCreateOrderOpts.senderAddress,
+            makerFee: createOrderOpts.makerFee || defaultCreateOrderOpts.makerFee,
+            takerFee: createOrderOpts.takerFee || defaultCreateOrderOpts.takerFee,
+            feeRecipientAddress: createOrderOpts.feeRecipientAddress || defaultCreateOrderOpts.feeRecipientAddress,
+            salt: createOrderOpts.salt || defaultCreateOrderOpts.salt,
+            expirationTimeSeconds:
+                createOrderOpts.expirationTimeSeconds || defaultCreateOrderOpts.expirationTimeSeconds,
         };
+        return order;
+    },
+    async createSignedOrderAsync(
+        provider: Provider,
+        makerAddress: string,
+        makerAssetAmount: BigNumber,
+        makerAssetData: string,
+        takerAssetAmount: BigNumber,
+        takerAssetData: string,
+        exchangeAddress: string,
+        createOrderOpts?: CreateOrderOpts,
+    ): Promise<SignedOrder> {
+        const order = orderFactory.createOrder(
+            makerAddress,
+            makerAssetAmount,
+            makerAssetData,
+            takerAssetAmount,
+            takerAssetData,
+            exchangeAddress,
+            createOrderOpts,
+        );
         const orderHash = orderHashUtils.getOrderHashHex(order);
         const messagePrefixOpts = {
             prefixType: MessagePrefixType.EthSign,
@@ -56,6 +70,26 @@ export const orderFactory = {
     },
 };
 
+function generateDefaultCreateOrderOpts(): {
+    takerAddress: string;
+    senderAddress: string;
+    makerFee: BigNumber;
+    takerFee: BigNumber;
+    feeRecipientAddress: string;
+    salt: BigNumber;
+    expirationTimeSeconds: BigNumber;
+} {
+    return {
+        takerAddress: constants.NULL_ADDRESS,
+        senderAddress: constants.NULL_ADDRESS,
+        makerFee: constants.ZERO_AMOUNT,
+        takerFee: constants.ZERO_AMOUNT,
+        feeRecipientAddress: constants.NULL_ADDRESS,
+        salt: generatePseudoRandomSalt(),
+        expirationTimeSeconds: constants.INFINITE_TIMESTAMP_SEC,
+    };
+}
+
 function getVRSHexString(ecSignature: ECSignature): string {
     const ETH_SIGN_SIGNATURE_TYPE = '03';
     const vrs = `${intToHex(ecSignature.v)}${ethUtil.stripHexPrefix(ecSignature.r)}${ethUtil.stripHexPrefix(
diff --git a/packages/order-utils/src/types.ts b/packages/order-utils/src/types.ts
index b08e74e71..f44e94349 100644
--- a/packages/order-utils/src/types.ts
+++ b/packages/order-utils/src/types.ts
@@ -1,3 +1,5 @@
+import { BigNumber } from '@0xproject/utils';
+
 export enum OrderError {
     InvalidSignature = 'INVALID_SIGNATURE',
 }
@@ -51,3 +53,13 @@ export enum EIP712Types {
     String = 'string',
     Uint256 = 'uint256',
 }
+
+export interface CreateOrderOpts {
+    takerAddress?: string;
+    senderAddress?: string;
+    makerFee?: BigNumber;
+    takerFee?: BigNumber;
+    feeRecipientAddress?: string;
+    salt?: BigNumber;
+    expirationTimeSeconds?: BigNumber;
+}
diff --git a/packages/order-utils/test/market_utils_test.ts b/packages/order-utils/test/market_utils_test.ts
new file mode 100644
index 000000000..21c0a4802
--- /dev/null
+++ b/packages/order-utils/test/market_utils_test.ts
@@ -0,0 +1,280 @@
+import { BigNumber } from '@0xproject/utils';
+import * as chai from 'chai';
+import 'mocha';
+
+import { constants, marketUtils } from '../src';
+
+import { chaiSetup } from './utils/chai_setup';
+import { testOrderFactory } from './utils/test_order_factory';
+
+chaiSetup.configure();
+const expect = chai.expect;
+
+// tslint:disable: no-unused-expression
+describe('marketUtils', () => {
+    describe('#findOrdersThatCoverMakerAssetFillAmount', () => {
+        describe('no orders', () => {
+            it('returns empty and unchanged remainingFillAmount', async () => {
+                const fillAmount = new BigNumber(10);
+                const { resultOrders, remainingFillAmount } = marketUtils.findOrdersThatCoverMakerAssetFillAmount(
+                    [],
+                    [],
+                    fillAmount,
+                );
+                expect(resultOrders).to.be.empty;
+                expect(remainingFillAmount).to.be.bignumber.equal(fillAmount);
+            });
+        });
+        describe('orders are completely fillable', () => {
+            // generate three signed orders each with 10 units of makerAsset, 30 total
+            const makerAssetAmount = new BigNumber(10);
+            const inputOrders = testOrderFactory.generateTestSignedOrders(
+                {
+                    makerAssetAmount,
+                },
+                3,
+            );
+            // generate remainingFillableMakerAssetAmounts that equal the makerAssetAmount
+            const remainingFillableMakerAssetAmounts = [makerAssetAmount, makerAssetAmount, makerAssetAmount];
+            it('returns input orders and zero remainingFillAmount when input exactly matches requested fill amount', async () => {
+                // try to fill 20 units of makerAsset
+                // include 10 units of slippageBufferAmount
+                const fillAmount = new BigNumber(20);
+                const slippageBufferAmount = new BigNumber(10);
+                const { resultOrders, remainingFillAmount } = marketUtils.findOrdersThatCoverMakerAssetFillAmount(
+                    inputOrders,
+                    remainingFillableMakerAssetAmounts,
+                    fillAmount,
+                    slippageBufferAmount,
+                );
+                expect(resultOrders).to.be.deep.equal(inputOrders);
+                expect(remainingFillAmount).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            });
+            it('returns input orders and zero remainingFillAmount when input has more than requested fill amount', async () => {
+                // try to fill 15 units of makerAsset
+                // include 10 units of slippageBufferAmount
+                const fillAmount = new BigNumber(15);
+                const slippageBufferAmount = new BigNumber(10);
+                const { resultOrders, remainingFillAmount } = marketUtils.findOrdersThatCoverMakerAssetFillAmount(
+                    inputOrders,
+                    remainingFillableMakerAssetAmounts,
+                    fillAmount,
+                    slippageBufferAmount,
+                );
+                expect(resultOrders).to.be.deep.equal(inputOrders);
+                expect(remainingFillAmount).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            });
+            it('returns input orders and non-zero remainingFillAmount when input has less than requested fill amount', async () => {
+                // try to fill 30 units of makerAsset
+                // include 5 units of slippageBufferAmount
+                const fillAmount = new BigNumber(30);
+                const slippageBufferAmount = new BigNumber(5);
+                const { resultOrders, remainingFillAmount } = marketUtils.findOrdersThatCoverMakerAssetFillAmount(
+                    inputOrders,
+                    remainingFillableMakerAssetAmounts,
+                    fillAmount,
+                    slippageBufferAmount,
+                );
+                expect(resultOrders).to.be.deep.equal(inputOrders);
+                expect(remainingFillAmount).to.be.bignumber.equal(new BigNumber(5));
+            });
+            it('returns first order and zero remainingFillAmount when requested fill amount is exactly covered by the first order', async () => {
+                // try to fill 10 units of makerAsset
+                const fillAmount = new BigNumber(10);
+                const { resultOrders, remainingFillAmount } = marketUtils.findOrdersThatCoverMakerAssetFillAmount(
+                    inputOrders,
+                    remainingFillableMakerAssetAmounts,
+                    fillAmount,
+                );
+                expect(resultOrders).to.be.deep.equal([inputOrders[0]]);
+                expect(remainingFillAmount).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            });
+            it('returns first two orders and zero remainingFillAmount when requested fill amount is over covered by the first two order', async () => {
+                // try to fill 15 units of makerAsset
+                const fillAmount = new BigNumber(15);
+                const { resultOrders, remainingFillAmount } = marketUtils.findOrdersThatCoverMakerAssetFillAmount(
+                    inputOrders,
+                    remainingFillableMakerAssetAmounts,
+                    fillAmount,
+                );
+                expect(resultOrders).to.be.deep.equal([inputOrders[0], inputOrders[1]]);
+                expect(remainingFillAmount).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            });
+        });
+        describe('orders are partially fillable', () => {
+            // generate three signed orders each with 10 units of makerAsset, 30 total
+            const makerAssetAmount = new BigNumber(10);
+            const inputOrders = testOrderFactory.generateTestSignedOrders(
+                {
+                    makerAssetAmount,
+                },
+                3,
+            );
+            // generate remainingFillableMakerAssetAmounts that cover different partial fill scenarios
+            // 1. order is completely filled already
+            // 2. order is partially fillable
+            // 3. order is completely fillable
+            const remainingFillableMakerAssetAmounts = [constants.ZERO_AMOUNT, new BigNumber(5), makerAssetAmount];
+            it('returns last two orders and non-zero remainingFillAmount when trying to fill original makerAssetAmounts', async () => {
+                // try to fill 30 units of makerAsset
+                const fillAmount = new BigNumber(30);
+                const { resultOrders, remainingFillAmount } = marketUtils.findOrdersThatCoverMakerAssetFillAmount(
+                    inputOrders,
+                    remainingFillableMakerAssetAmounts,
+                    fillAmount,
+                );
+                expect(resultOrders).to.be.deep.equal([inputOrders[1], inputOrders[2]]);
+                expect(remainingFillAmount).to.be.bignumber.equal(new BigNumber(15));
+            });
+        });
+    });
+    describe('#findFeeOrdersThatCoverFeesForTargetOrders', () => {
+        // generate three signed fee orders each with 10 units of ZRX, 30 total
+        const zrxAmount = new BigNumber(10);
+        const inputFeeOrders = testOrderFactory.generateTestSignedOrders(
+            {
+                makerAssetAmount: zrxAmount,
+            },
+            3,
+        );
+        // generate remainingFillableFeeAmounts that equal the zrxAmount
+        const remainingFillableFeeAmounts = [zrxAmount, zrxAmount, zrxAmount];
+        describe('no target orders', () => {
+            it('returns empty and zero remainingFeeAmount', async () => {
+                const { resultOrders, remainingFeeAmount } = marketUtils.findFeeOrdersThatCoverFeesForTargetOrders(
+                    [],
+                    [],
+                    inputFeeOrders,
+                    remainingFillableFeeAmounts,
+                );
+                expect(resultOrders).to.be.empty;
+                expect(remainingFeeAmount).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            });
+        });
+        describe('no fee orders', () => {
+            // generate three signed orders each with 10 units of makerAsset, 30 total
+            // each signed order requires 10 units of takerFee
+            const makerAssetAmount = new BigNumber(10);
+            const takerFee = new BigNumber(10);
+            const inputOrders = testOrderFactory.generateTestSignedOrders(
+                {
+                    makerAssetAmount,
+                    takerFee,
+                },
+                3,
+            );
+            // generate remainingFillableMakerAssetAmounts that equal the makerAssetAmount
+            const remainingFillableMakerAssetAmounts = [makerAssetAmount, makerAssetAmount, makerAssetAmount];
+            it('returns empty and non-zero remainingFeeAmount', async () => {
+                const { resultOrders, remainingFeeAmount } = marketUtils.findFeeOrdersThatCoverFeesForTargetOrders(
+                    inputOrders,
+                    remainingFillableMakerAssetAmounts,
+                    [],
+                    [],
+                );
+                expect(resultOrders).to.be.empty;
+                expect(remainingFeeAmount).to.be.bignumber.equal(new BigNumber(30));
+            });
+        });
+        describe('target orders have no fees', () => {
+            // generate three signed orders each with 10 units of makerAsset, 30 total
+            const makerAssetAmount = new BigNumber(10);
+            const inputOrders = testOrderFactory.generateTestSignedOrders(
+                {
+                    makerAssetAmount,
+                },
+                3,
+            );
+            // generate remainingFillableMakerAssetAmounts that equal the makerAssetAmount
+            const remainingFillableMakerAssetAmounts = [makerAssetAmount, makerAssetAmount, makerAssetAmount];
+            it('returns empty and zero remainingFeeAmount', async () => {
+                const { resultOrders, remainingFeeAmount } = marketUtils.findFeeOrdersThatCoverFeesForTargetOrders(
+                    inputOrders,
+                    remainingFillableMakerAssetAmounts,
+                    inputFeeOrders,
+                    remainingFillableFeeAmounts,
+                );
+                expect(resultOrders).to.be.empty;
+                expect(remainingFeeAmount).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            });
+        });
+        describe('target orders require fees and are completely fillable', () => {
+            // generate three signed orders each with 10 units of makerAsset, 30 total
+            // each signed order requires 10 units of takerFee
+            const makerAssetAmount = new BigNumber(10);
+            const takerFee = new BigNumber(10);
+            const inputOrders = testOrderFactory.generateTestSignedOrders(
+                {
+                    makerAssetAmount,
+                    takerFee,
+                },
+                3,
+            );
+            // generate remainingFillableMakerAssetAmounts that equal the makerAssetAmount
+            const remainingFillableMakerAssetAmounts = [makerAssetAmount, makerAssetAmount, makerAssetAmount];
+            it('returns input fee orders and zero remainingFeeAmount', async () => {
+                const { resultOrders, remainingFeeAmount } = marketUtils.findFeeOrdersThatCoverFeesForTargetOrders(
+                    inputOrders,
+                    remainingFillableMakerAssetAmounts,
+                    inputFeeOrders,
+                    remainingFillableFeeAmounts,
+                );
+                expect(resultOrders).to.be.deep.equal(inputFeeOrders);
+                expect(remainingFeeAmount).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            });
+        });
+        describe('target orders require fees and are partially fillable', () => {
+            // generate three signed orders each with 10 units of makerAsset, 30 total
+            // each signed order requires 10 units of takerFee
+            const makerAssetAmount = new BigNumber(10);
+            const takerFee = new BigNumber(10);
+            const inputOrders = testOrderFactory.generateTestSignedOrders(
+                {
+                    makerAssetAmount,
+                    takerFee,
+                },
+                3,
+            );
+            // generate remainingFillableMakerAssetAmounts that cover different partial fill scenarios
+            // 1. order is completely filled already
+            // 2. order is partially fillable
+            // 3. order is completely fillable
+            const remainingFillableMakerAssetAmounts = [constants.ZERO_AMOUNT, new BigNumber(5), makerAssetAmount];
+            it('returns first two input fee orders and zero remainingFeeAmount', async () => {
+                const { resultOrders, remainingFeeAmount } = marketUtils.findFeeOrdersThatCoverFeesForTargetOrders(
+                    inputOrders,
+                    remainingFillableMakerAssetAmounts,
+                    inputFeeOrders,
+                    remainingFillableFeeAmounts,
+                );
+                expect(resultOrders).to.be.deep.equal([inputFeeOrders[0], inputFeeOrders[1]]);
+                expect(remainingFeeAmount).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            });
+        });
+        describe('target orders require more fees than available', () => {
+            // generate three signed orders each with 10 units of makerAsset, 30 total
+            // each signed order requires 20 units of takerFee
+            const makerAssetAmount = new BigNumber(10);
+            const takerFee = new BigNumber(20);
+            const inputOrders = testOrderFactory.generateTestSignedOrders(
+                {
+                    makerAssetAmount,
+                    takerFee,
+                },
+                3,
+            );
+            // generate remainingFillableMakerAssetAmounts that equal the makerAssetAmount
+            const remainingFillableMakerAssetAmounts = [makerAssetAmount, makerAssetAmount, makerAssetAmount];
+            it('returns input fee orders and non-zero remainingFeeAmount', async () => {
+                const { resultOrders, remainingFeeAmount } = marketUtils.findFeeOrdersThatCoverFeesForTargetOrders(
+                    inputOrders,
+                    remainingFillableMakerAssetAmounts,
+                    inputFeeOrders,
+                    remainingFillableFeeAmounts,
+                );
+                expect(resultOrders).to.be.deep.equal(inputFeeOrders);
+                expect(remainingFeeAmount).to.be.bignumber.equal(new BigNumber(30));
+            });
+        });
+    });
+});
diff --git a/packages/order-utils/test/signature_utils_test.ts b/packages/order-utils/test/signature_utils_test.ts
index 5714f9671..baae2b414 100644
--- a/packages/order-utils/test/signature_utils_test.ts
+++ b/packages/order-utils/test/signature_utils_test.ts
@@ -22,7 +22,8 @@ describe('Signature utils', () => {
         let address = '0x5409ed021d9299bf6814279a6a1411a7e866a631';
 
         it("should return false if the data doesn't pertain to the signature & address", async () => {
-            expect(await isValidSignatureAsync(provider, '0x0', ethSignSignature, address)).to.be.false();
+            const bytes32Zeros = '0x0000000000000000000000000000000000000000000000000000000000000000';
+            expect(await isValidSignatureAsync(provider, bytes32Zeros, ethSignSignature, address)).to.be.false();
         });
         it("should return false if the address doesn't pertain to the signature & data", async () => {
             const validUnrelatedAddress = '0x8b0292b11a196601ed2ce54b665cafeca0347d42';
diff --git a/packages/order-utils/test/utils/test_order_factory.ts b/packages/order-utils/test/utils/test_order_factory.ts
new file mode 100644
index 000000000..75dc6f1f2
--- /dev/null
+++ b/packages/order-utils/test/utils/test_order_factory.ts
@@ -0,0 +1,32 @@
+import { Order, SignedOrder } from '@0xproject/types';
+import * as _ from 'lodash';
+
+import { constants, orderFactory } from '../../src';
+
+const BASE_TEST_ORDER: Order = orderFactory.createOrder(
+    constants.NULL_ADDRESS,
+    constants.ZERO_AMOUNT,
+    constants.NULL_ADDRESS,
+    constants.ZERO_AMOUNT,
+    constants.NULL_ADDRESS,
+    constants.NULL_ADDRESS,
+);
+const BASE_TEST_SIGNED_ORDER: SignedOrder = {
+    ...BASE_TEST_ORDER,
+    signature: constants.NULL_BYTES,
+};
+
+export const testOrderFactory = {
+    generateTestSignedOrder(partialOrder: Partial<SignedOrder>): SignedOrder {
+        return transformObject(BASE_TEST_SIGNED_ORDER, partialOrder);
+    },
+    generateTestSignedOrders(partialOrder: Partial<SignedOrder>, numOrders: number): SignedOrder[] {
+        const baseTestOrders = _.map(_.range(numOrders), () => BASE_TEST_SIGNED_ORDER);
+        return _.map(baseTestOrders, order => transformObject(order, partialOrder));
+    },
+};
+
+function transformObject<T>(input: T, transformation: Partial<T>): T {
+    const copy = _.cloneDeep(input);
+    return _.assign(copy, transformation);
+}