Merge branch 'development' into feature/website/top-bar-redesign

* development: (63 commits)
  Update The Ocean logo
  Fix artifacts paths
  Create an artifacts folder
  Introduce a var
  Add removeHexPrefix util method
  CHeck if ABI exists
  Improve the readability of the check for should compile
  Use named constants
  Add a comment
  Fix comments
  Rename args to constructor-args
  Fix a typo
  Define a separator const
  Move artifacts from src/artifacts to artifacts/v1
  Fix sol-cov to work with the new artifacts format
  Implement new artifacts format
  Publish
  Updated CHANGELOGS
  Make node types a dependency
  Fix type errors in CSS properties
  ...

18 files changed, 162 insertions, 451 deletions

diff --git a/packages/0x.js/CHANGELOG.json b/packages/0x.js/CHANGELOG.json
index ef4bb1e07..bdc575903 100644
--- a/packages/0x.js/CHANGELOG.json
+++ b/packages/0x.js/CHANGELOG.json
@@ -1,12 +1,43 @@
 [
     {
-        "version": "0.36.4",
+        "timestamp": 1525477860,
+        "version": "0.37.2",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
+    {
+        "timestamp": 1525453812,
+        "version": "0.37.1",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
+    {
+        "version": "0.37.0",
         "changes": [
             {
                 "note": "Fixed expiration watcher comparator to handle orders with equal expiration times",
                 "pr": 526
+            },
+            {
+                "note": "Update Web3 Provider Engine to 14.0.4",
+                "pr": 555
+            },
+            {
+                "note": "Add `zeroEx.getProvider()`",
+                "pr": 559
+            },
+            {
+                "note": "Move `ZeroExError.InvalidSignature` to `@0xproject/order-utils` `OrderError.InvalidSignature`",
+                "pr": 559
             }
-        ]
+        ],
+        "timestamp": 1525428773
     },
     {
         "version": "0.36.3",
diff --git a/packages/0x.js/CHANGELOG.md b/packages/0x.js/CHANGELOG.md
index f800b86db..353e0de29 100644
--- a/packages/0x.js/CHANGELOG.md
+++ b/packages/0x.js/CHANGELOG.md
@@ -5,6 +5,21 @@ Edit the package's CHANGELOG.json file only.
 
 CHANGELOG
 
+## v0.37.2 - _May 5, 2018_
+
+    * Dependencies updated
+
+## v0.37.1 - _May 4, 2018_
+
+    * Dependencies updated
+
+## v0.37.0 - _May 4, 2018_
+
+    * Fixed expiration watcher comparator to handle orders with equal expiration times (#526)
+    * Update Web3 Provider Engine to 14.0.4 (#555)
+    * Add `zeroEx.getProvider()` (#559)
+    * Move `ZeroExError.InvalidSignature` to `@0xproject/order-utils` `OrderError.InvalidSignature` (#559)
+
 ## v0.36.3 - _April 18, 2018_
 
     * Move @0xproject/migrations to devDependencies
diff --git a/packages/0x.js/package.json b/packages/0x.js/package.json
index e7cdff09e..a23e01938 100644
--- a/packages/0x.js/package.json
+++ b/packages/0x.js/package.json
@@ -1,6 +1,6 @@
 {
     "name": "0x.js",
-    "version": "0.36.3",
+    "version": "0.37.2",
     "description": "A javascript library for interacting with the 0x protocol",
     "keywords": [
         "0x.js",
@@ -21,7 +21,7 @@
         "test": "run-s clean test:commonjs",
         "test:coverage": "nyc npm run test --all && yarn coverage:report:lcov",
         "coverage:report:lcov": "nyc report --reporter=text-lcov > coverage/lcov.info",
-        "update_artifacts": "for i in ${npm_package_config_contracts}; do copyfiles -u 4 ../migrations/src/artifacts/$i.json test/artifacts; done;",
+        "update_artifacts": "for i in ${npm_package_config_contracts}; do copyfiles -u 4 ../migrations/artifacts/1.0.0/$i.json test/artifacts; done;",
         "clean": "shx rm -rf _bundles lib test_temp scripts",
         "build:umd:prod": "NODE_ENV=production webpack",
         "build:commonjs": "tsc && yarn update_artifacts && copyfiles -u 2 './src/compact_artifacts/**/*.json' ./lib/src/compact_artifacts && copyfiles -u 3 './lib/src/monorepo_scripts/**/*' ./scripts",
@@ -61,12 +61,12 @@
         "node": ">=6.0.0"
     },
     "devDependencies": {
-        "@0xproject/deployer": "^0.4.1",
-        "@0xproject/dev-utils": "^0.3.6",
-        "@0xproject/migrations": "^0.0.3",
-        "@0xproject/monorepo-scripts": "^0.1.18",
-        "@0xproject/subproviders": "^0.9.0",
-        "@0xproject/tslint-config": "^0.4.16",
+        "@0xproject/deployer": "^0.4.3",
+        "@0xproject/dev-utils": "^0.4.1",
+        "@0xproject/migrations": "^0.0.5",
+        "@0xproject/monorepo-scripts": "^0.1.19",
+        "@0xproject/subproviders": "^0.10.1",
+        "@0xproject/tslint-config": "^0.4.17",
         "@types/bintrees": "^1.0.2",
         "@types/lodash": "4.14.104",
         "@types/mocha": "^2.2.42",
@@ -93,17 +93,18 @@
         "tslint": "5.8.0",
         "typedoc": "0xProject/typedoc",
         "typescript": "2.7.1",
-        "web3-provider-engine": "^13.0.1",
+        "web3-provider-engine": "^14.0.4",
         "webpack": "^3.1.0"
     },
     "dependencies": {
-        "@0xproject/assert": "^0.2.7",
-        "@0xproject/base-contract": "^0.2.1",
-        "@0xproject/json-schemas": "^0.7.21",
-        "@0xproject/types": "^0.6.1",
-        "@0xproject/typescript-typings": "^0.2.0",
-        "@0xproject/utils": "^0.5.2",
-        "@0xproject/web3-wrapper": "^0.6.1",
+        "@0xproject/assert": "^0.2.9",
+        "@0xproject/base-contract": "^0.3.1",
+        "@0xproject/json-schemas": "^0.7.23",
+        "@0xproject/order-utils": "^0.0.4",
+        "@0xproject/types": "^0.6.3",
+        "@0xproject/typescript-typings": "^0.3.1",
+        "@0xproject/utils": "^0.6.1",
+        "@0xproject/web3-wrapper": "^0.6.3",
         "bintrees": "^1.0.2",
         "bn.js": "^4.11.8",
         "ethereumjs-abi": "^0.6.4",
diff --git a/packages/0x.js/src/0x.ts b/packages/0x.js/src/0x.ts
index 94d97c23e..78f9f6beb 100644
--- a/packages/0x.js/src/0x.ts
+++ b/packages/0x.js/src/0x.ts
@@ -1,4 +1,11 @@
 import { schemas, SchemaValidator } from '@0xproject/json-schemas';
+import {
+    generatePseudoRandomSalt,
+    getOrderHashHex,
+    isValidOrderHash,
+    isValidSignature,
+    signOrderHashAsync,
+} from '@0xproject/order-utils';
 import { ECSignature, Order, Provider, SignedOrder, TransactionReceiptWithDecodedLogs } from '@0xproject/types';
 import { AbiDecoder, BigNumber, intervalUtils } from '@0xproject/utils';
 import { Web3Wrapper } from '@0xproject/web3-wrapper';
@@ -19,7 +26,6 @@ import { OrderStateWatcherConfig, ZeroExConfig, ZeroExError } from './types';
 import { assert } from './utils/assert';
 import { constants } from './utils/constants';
 import { decorators } from './utils/decorators';
-import { signatureUtils } from './utils/signature_utils';
 import { utils } from './utils/utils';
 
 /**
@@ -33,7 +39,6 @@ export class ZeroEx {
      * this constant for your convenience.
      */
     public static NULL_ADDRESS = constants.NULL_ADDRESS;
-
     /**
      * An instance of the ExchangeWrapper class containing methods for interacting with the 0x Exchange smart contract.
      */
@@ -59,6 +64,15 @@ export class ZeroEx {
     public proxy: TokenTransferProxyWrapper;
     private _web3Wrapper: Web3Wrapper;
     /**
+     * Generates a pseudo-random 256-bit salt.
+     * The salt can be included in a 0x order, ensuring that the order generates a unique orderHash
+     * and will not collide with other outstanding orders that are identical in all other parameters.
+     * @return  A pseudo-random 256-bit number that can be used as a salt.
+     */
+    public static generatePseudoRandomSalt(): BigNumber {
+        return generatePseudoRandomSalt();
+    }
+    /**
      * Verifies that the elliptic curve signature `signature` was generated
      * by signing `data` with the private key corresponding to the `signerAddress` address.
      * @param   data          The hex encoded data signed by the supplied signature.
@@ -67,27 +81,15 @@ export class ZeroEx {
      * @return  Whether the signature is valid for the supplied signerAddress and data.
      */
     public static isValidSignature(data: string, signature: ECSignature, signerAddress: string): boolean {
-        assert.isHexString('data', data);
-        assert.doesConformToSchema('signature', signature, schemas.ecSignatureSchema);
-        assert.isETHAddressHex('signerAddress', signerAddress);
-        const normalizedSignerAddress = signerAddress.toLowerCase();
-
-        const isValidSignature = signatureUtils.isValidSignature(data, signature, normalizedSignerAddress);
-        return isValidSignature;
+        return isValidSignature(data, signature, signerAddress);
     }
     /**
-     * Generates a pseudo-random 256-bit salt.
-     * The salt can be included in a 0x order, ensuring that the order generates a unique orderHash
-     * and will not collide with other outstanding orders that are identical in all other parameters.
-     * @return  A pseudo-random 256-bit number that can be used as a salt.
+     * Computes the orderHash for a supplied order.
+     * @param   order   An object that conforms to the Order or SignedOrder interface definitions.
+     * @return  The resulting orderHash from hashing the supplied order.
      */
-    public static generatePseudoRandomSalt(): BigNumber {
-        // BigNumber.random returns a pseudo-random number between 0 & 1 with a passed in number of decimal places.
-        // Source: https://mikemcl.github.io/bignumber.js/#random
-        const randomNumber = BigNumber.random(constants.MAX_DIGITS_IN_UNSIGNED_256_INT);
-        const factor = new BigNumber(10).pow(constants.MAX_DIGITS_IN_UNSIGNED_256_INT - 1);
-        const salt = randomNumber.times(factor).round();
-        return salt;
+    public static getOrderHashHex(order: Order | SignedOrder): string {
+        return getOrderHashHex(order);
     }
     /**
      * Checks if the supplied hex encoded order hash is valid.
@@ -97,12 +99,7 @@ export class ZeroEx {
      * @return  Whether the supplied orderHash has the expected format.
      */
     public static isValidOrderHash(orderHash: string): boolean {
-        // Since this method can be called to check if any arbitrary string conforms to an orderHash's
-        // format, we only assert that we were indeed passed a string.
-        assert.isString('orderHash', orderHash);
-        const schemaValidator = new SchemaValidator();
-        const isValidOrderHash = schemaValidator.validate(orderHash, schemas.orderHashSchema).valid;
-        return isValidOrderHash;
+        return isValidOrderHash(orderHash);
     }
     /**
      * A unit amount is defined as the amount of a token above the specified decimal places (integer part).
@@ -133,17 +130,6 @@ export class ZeroEx {
         return baseUnitAmount;
     }
     /**
-     * Computes the orderHash for a supplied order.
-     * @param   order   An object that conforms to the Order or SignedOrder interface definitions.
-     * @return  The resulting orderHash from hashing the supplied order.
-     */
-    @decorators.syncZeroExErrorHandler
-    public static getOrderHashHex(order: Order | SignedOrder): string {
-        assert.doesConformToSchema('order', order, schemas.orderSchema);
-        const orderHashHex = utils.getOrderHashHex(order);
-        return orderHashHex;
-    }
-    /**
      * Instantiates a new ZeroEx instance that provides the public interface to the 0x.js library.
      * @param   provider    The Provider instance you would like the 0x.js library to use for interacting with
      *                      the Ethereum network.
@@ -205,6 +191,13 @@ export class ZeroEx {
         (this.etherToken as any)._setNetworkId(networkId);
     }
     /**
+     * Get the provider instance currently used by 0x.js
+     * @return  Web3 provider instance
+     */
+    public getProvider(): Provider {
+        return this._web3Wrapper.getProvider();
+    }
+    /**
      * Get user Ethereum addresses available through the supplied web3 provider available for sending transactions.
      * @return  An array of available user Ethereum addresses.
      */
@@ -229,41 +222,12 @@ export class ZeroEx {
         signerAddress: string,
         shouldAddPersonalMessagePrefix: boolean,
     ): Promise<ECSignature> {
-        assert.isHexString('orderHash', orderHash);
-        await assert.isSenderAddressAsync('signerAddress', signerAddress, this._web3Wrapper);
-        const normalizedSignerAddress = signerAddress.toLowerCase();
-
-        let msgHashHex = orderHash;
-        if (shouldAddPersonalMessagePrefix) {
-            const orderHashBuff = ethUtil.toBuffer(orderHash);
-            const msgHashBuff = ethUtil.hashPersonalMessage(orderHashBuff);
-            msgHashHex = ethUtil.bufferToHex(msgHashBuff);
-        }
-
-        const signature = await this._web3Wrapper.signMessageAsync(normalizedSignerAddress, msgHashHex);
-
-        // HACK: There is no consensus on whether the signatureHex string should be formatted as
-        // v + r + s OR r + s + v, and different clients (even different versions of the same client)
-        // return the signature params in different orders. In order to support all client implementations,
-        // we parse the signature in both ways, and evaluate if either one is a valid signature.
-        const validVParamValues = [27, 28];
-        const ecSignatureVRS = signatureUtils.parseSignatureHexAsVRS(signature);
-        if (_.includes(validVParamValues, ecSignatureVRS.v)) {
-            const isValidVRSSignature = ZeroEx.isValidSignature(orderHash, ecSignatureVRS, normalizedSignerAddress);
-            if (isValidVRSSignature) {
-                return ecSignatureVRS;
-            }
-        }
-
-        const ecSignatureRSV = signatureUtils.parseSignatureHexAsRSV(signature);
-        if (_.includes(validVParamValues, ecSignatureRSV.v)) {
-            const isValidRSVSignature = ZeroEx.isValidSignature(orderHash, ecSignatureRSV, normalizedSignerAddress);
-            if (isValidRSVSignature) {
-                return ecSignatureRSV;
-            }
-        }
-
-        throw new Error(ZeroExError.InvalidSignature);
+        return signOrderHashAsync(
+            this._web3Wrapper.getProvider(),
+            orderHash,
+            signerAddress,
+            shouldAddPersonalMessagePrefix,
+        );
     }
     /**
      * Waits for a transaction to be mined and returns the transaction receipt.
diff --git a/packages/0x.js/src/contract_wrappers/exchange_wrapper.ts b/packages/0x.js/src/contract_wrappers/exchange_wrapper.ts
index 7cda70f16..6ddaaaf4f 100644
--- a/packages/0x.js/src/contract_wrappers/exchange_wrapper.ts
+++ b/packages/0x.js/src/contract_wrappers/exchange_wrapper.ts
@@ -1,4 +1,5 @@
 import { schemas } from '@0xproject/json-schemas';
+import { getOrderHashHex } from '@0xproject/order-utils';
 import {
     BlockParamLiteral,
     DecodedLogArgs,
@@ -570,7 +571,7 @@ export class ExchangeWrapper extends ContractWrapper {
             ? SHOULD_VALIDATE_BY_DEFAULT
             : orderTransactionOpts.shouldValidate;
         if (shouldValidate) {
-            const orderHash = utils.getOrderHashHex(order);
+            const orderHash = getOrderHashHex(order);
             const unavailableTakerTokenAmount = await this.getUnavailableTakerAmountAsync(orderHash);
             OrderValidationUtils.validateCancelOrderThrowIfInvalid(
                 order,
@@ -629,7 +630,7 @@ export class ExchangeWrapper extends ContractWrapper {
             : orderTransactionOpts.shouldValidate;
         if (shouldValidate) {
             for (const orderCancellationRequest of orderCancellationRequests) {
-                const orderHash = utils.getOrderHashHex(orderCancellationRequest.order);
+                const orderHash = getOrderHashHex(orderCancellationRequest.order);
                 const unavailableTakerTokenAmount = await this.getUnavailableTakerAmountAsync(orderHash);
                 OrderValidationUtils.validateCancelOrderThrowIfInvalid(
                     orderCancellationRequest.order,
@@ -801,7 +802,7 @@ export class ExchangeWrapper extends ContractWrapper {
     ): Promise<void> {
         assert.doesConformToSchema('order', order, schemas.orderSchema);
         assert.isValidBaseUnitAmount('cancelTakerTokenAmount', cancelTakerTokenAmount);
-        const orderHash = utils.getOrderHashHex(order);
+        const orderHash = getOrderHashHex(order);
         const unavailableTakerTokenAmount = await this.getUnavailableTakerAmountAsync(orderHash);
         OrderValidationUtils.validateCancelOrderThrowIfInvalid(
             order,
diff --git a/packages/0x.js/src/types.ts b/packages/0x.js/src/types.ts
index 151204928..ae9f98c5f 100644
--- a/packages/0x.js/src/types.ts
+++ b/packages/0x.js/src/types.ts
@@ -27,7 +27,6 @@ export enum ZeroExError {
     TokenContractDoesNotExist = 'TOKEN_CONTRACT_DOES_NOT_EXIST',
     UnhandledError = 'UNHANDLED_ERROR',
     UserHasNoAssociatedAddress = 'USER_HAS_NO_ASSOCIATED_ADDRESSES',
-    InvalidSignature = 'INVALID_SIGNATURE',
     ContractNotDeployedOnNetwork = 'CONTRACT_NOT_DEPLOYED_ON_NETWORK',
     InsufficientAllowanceForTransfer = 'INSUFFICIENT_ALLOWANCE_FOR_TRANSFER',
     InsufficientBalanceForTransfer = 'INSUFFICIENT_BALANCE_FOR_TRANSFER',
diff --git a/packages/0x.js/src/utils/assert.ts b/packages/0x.js/src/utils/assert.ts
index 5e8004cd0..2588a4d09 100644
--- a/packages/0x.js/src/utils/assert.ts
+++ b/packages/0x.js/src/utils/assert.ts
@@ -8,13 +8,13 @@ import { BigNumber } from '@0xproject/utils';
 import { Web3Wrapper } from '@0xproject/web3-wrapper';
 import * as _ from 'lodash';
 
-import { signatureUtils } from '../utils/signature_utils';
+import { isValidSignature } from '@0xproject/order-utils';
 
 export const assert = {
     ...sharedAssert,
     isValidSignature(orderHash: string, ecSignature: ECSignature, signerAddress: string) {
-        const isValidSignature = signatureUtils.isValidSignature(orderHash, ecSignature, signerAddress);
-        this.assert(isValidSignature, `Expected order with hash '${orderHash}' to have a valid signature`);
+        const isValid = isValidSignature(orderHash, ecSignature, signerAddress);
+        this.assert(isValid, `Expected order with hash '${orderHash}' to have a valid signature`);
     },
     async isSenderAddressAsync(
         variableName: string,
@@ -28,8 +28,4 @@ export const assert = {
             `Specified ${variableName} ${senderAddressHex} isn't available through the supplied web3 provider`,
         );
     },
-    async isUserAddressAvailableAsync(web3Wrapper: Web3Wrapper): Promise<void> {
-        const availableAddresses = await web3Wrapper.getAvailableAddressesAsync();
-        this.assert(!_.isEmpty(availableAddresses), 'No addresses were available on the provided web3 provider');
-    },
 };
diff --git a/packages/0x.js/src/utils/constants.ts b/packages/0x.js/src/utils/constants.ts
index 06beec8e2..07da6745d 100644
--- a/packages/0x.js/src/utils/constants.ts
+++ b/packages/0x.js/src/utils/constants.ts
@@ -3,7 +3,6 @@ import { BigNumber } from '@0xproject/utils';
 export const constants = {
     NULL_ADDRESS: '0x0000000000000000000000000000000000000000',
     TESTRPC_NETWORK_ID: 50,
-    MAX_DIGITS_IN_UNSIGNED_256_INT: 78,
     INVALID_JUMP_PATTERN: 'invalid JUMP at',
     OUT_OF_GAS_PATTERN: 'out of gas',
     INVALID_TAKER_FORMAT: 'instance.taker is not of a type(s) string',
diff --git a/packages/0x.js/src/utils/exchange_transfer_simulator.ts b/packages/0x.js/src/utils/exchange_transfer_simulator.ts
index 9a920c643..f8301f5c2 100644
--- a/packages/0x.js/src/utils/exchange_transfer_simulator.ts
+++ b/packages/0x.js/src/utils/exchange_transfer_simulator.ts
@@ -5,6 +5,7 @@ import * as _ from 'lodash';
 import { TokenWrapper } from '../contract_wrappers/token_wrapper';
 import { BalanceAndProxyAllowanceLazyStore } from '../stores/balance_proxy_allowance_lazy_store';
 import { ExchangeContractErrs, TradeSide, TransferType } from '../types';
+import { constants } from '../utils/constants';
 
 enum FailureReason {
     Balance = 'balance',
@@ -66,6 +67,13 @@ export class ExchangeTransferSimulator {
         tradeSide: TradeSide,
         transferType: TransferType,
     ): Promise<void> {
+        // HACK: When simulating an open order (e.g taker is NULL_ADDRESS), we don't want to adjust balances/
+        // allowances for the taker. We do however, want to increase the balance of the maker since the maker
+        // might be relying on those funds to fill subsequent orders or pay the order's fees.
+        if (from === constants.NULL_ADDRESS && tradeSide === TradeSide.Taker) {
+            await this._increaseBalanceAsync(tokenAddress, to, amountInBaseUnits);
+            return;
+        }
         const balance = await this._store.getBalanceAsync(tokenAddress, from);
         const proxyAllowance = await this._store.getProxyAllowanceAsync(tokenAddress, from);
         if (proxyAllowance.lessThan(amountInBaseUnits)) {
diff --git a/packages/0x.js/src/utils/order_validation_utils.ts b/packages/0x.js/src/utils/order_validation_utils.ts
index f32bf43d0..a13c3dc04 100644
--- a/packages/0x.js/src/utils/order_validation_utils.ts
+++ b/packages/0x.js/src/utils/order_validation_utils.ts
@@ -1,3 +1,4 @@
+import { getOrderHashHex, OrderError } from '@0xproject/order-utils';
 import { Order, SignedOrder } from '@0xproject/types';
 import { BigNumber } from '@0xproject/utils';
 import * as _ from 'lodash';
@@ -113,7 +114,7 @@ export class OrderValidationUtils {
         zrxTokenAddress: string,
         expectedFillTakerTokenAmount?: BigNumber,
     ): Promise<void> {
-        const orderHash = utils.getOrderHashHex(signedOrder);
+        const orderHash = getOrderHashHex(signedOrder);
         const unavailableTakerTokenAmount = await this._exchangeWrapper.getUnavailableTakerAmountAsync(orderHash);
         OrderValidationUtils._validateRemainingFillAmountNotZeroOrThrow(
             signedOrder.takerTokenAmount,
@@ -124,31 +125,12 @@ export class OrderValidationUtils {
         if (!_.isUndefined(expectedFillTakerTokenAmount)) {
             fillTakerTokenAmount = expectedFillTakerTokenAmount;
         }
-        const fillMakerTokenAmount = OrderValidationUtils._getPartialAmount(
+        await OrderValidationUtils.validateFillOrderBalancesAllowancesThrowIfInvalidAsync(
+            exchangeTradeEmulator,
+            signedOrder,
             fillTakerTokenAmount,
-            signedOrder.takerTokenAmount,
-            signedOrder.makerTokenAmount,
-        );
-        await exchangeTradeEmulator.transferFromAsync(
-            signedOrder.makerTokenAddress,
-            signedOrder.maker,
             signedOrder.taker,
-            fillMakerTokenAmount,
-            TradeSide.Maker,
-            TransferType.Trade,
-        );
-        const makerFeeAmount = OrderValidationUtils._getPartialAmount(
-            fillTakerTokenAmount,
-            signedOrder.takerTokenAmount,
-            signedOrder.makerFee,
-        );
-        await exchangeTradeEmulator.transferFromAsync(
             zrxTokenAddress,
-            signedOrder.maker,
-            signedOrder.feeRecipient,
-            makerFeeAmount,
-            TradeSide.Maker,
-            TransferType.Fee,
         );
     }
     public async validateFillOrderThrowIfInvalidAsync(
@@ -161,9 +143,9 @@ export class OrderValidationUtils {
         if (fillTakerTokenAmount.eq(0)) {
             throw new Error(ExchangeContractErrs.OrderFillAmountZero);
         }
-        const orderHash = utils.getOrderHashHex(signedOrder);
+        const orderHash = getOrderHashHex(signedOrder);
         if (!ZeroEx.isValidSignature(orderHash, signedOrder.ecSignature, signedOrder.maker)) {
-            throw new Error(ZeroExError.InvalidSignature);
+            throw new Error(OrderError.InvalidSignature);
         }
         const unavailableTakerTokenAmount = await this._exchangeWrapper.getUnavailableTakerAmountAsync(orderHash);
         OrderValidationUtils._validateRemainingFillAmountNotZeroOrThrow(
diff --git a/packages/0x.js/src/utils/signature_utils.ts b/packages/0x.js/src/utils/signature_utils.ts
deleted file mode 100644
index 46f167339..000000000
--- a/packages/0x.js/src/utils/signature_utils.ts
+++ /dev/null
@@ -1,45 +0,0 @@
-import { ECSignature } from '@0xproject/types';
-import * as ethUtil from 'ethereumjs-util';
-
-export const signatureUtils = {
-    isValidSignature(data: string, signature: ECSignature, signerAddress: string): boolean {
-        const dataBuff = ethUtil.toBuffer(data);
-        const msgHashBuff = ethUtil.hashPersonalMessage(dataBuff);
-        try {
-            const pubKey = ethUtil.ecrecover(
-                msgHashBuff,
-                signature.v,
-                ethUtil.toBuffer(signature.r),
-                ethUtil.toBuffer(signature.s),
-            );
-            const retrievedAddress = ethUtil.bufferToHex(ethUtil.pubToAddress(pubKey));
-            return retrievedAddress === signerAddress;
-        } catch (err) {
-            return false;
-        }
-    },
-    parseSignatureHexAsVRS(signatureHex: string): ECSignature {
-        const signatureBuffer = ethUtil.toBuffer(signatureHex);
-        let v = signatureBuffer[0];
-        if (v < 27) {
-            v += 27;
-        }
-        const r = signatureBuffer.slice(1, 33);
-        const s = signatureBuffer.slice(33, 65);
-        const ecSignature: ECSignature = {
-            v,
-            r: ethUtil.bufferToHex(r),
-            s: ethUtil.bufferToHex(s),
-        };
-        return ecSignature;
-    },
-    parseSignatureHexAsRSV(signatureHex: string): ECSignature {
-        const { v, r, s } = ethUtil.fromRpcSig(signatureHex);
-        const ecSignature: ECSignature = {
-            v,
-            r: ethUtil.bufferToHex(r),
-            s: ethUtil.bufferToHex(s),
-        };
-        return ecSignature;
-    },
-};
diff --git a/packages/0x.js/src/utils/utils.ts b/packages/0x.js/src/utils/utils.ts
index c8bcd907e..af1125632 100644
--- a/packages/0x.js/src/utils/utils.ts
+++ b/packages/0x.js/src/utils/utils.ts
@@ -1,59 +1,9 @@
-import { Order, SignedOrder, SolidityTypes } from '@0xproject/types';
 import { BigNumber } from '@0xproject/utils';
-import BN = require('bn.js');
-import * as ethABI from 'ethereumjs-abi';
-import * as ethUtil from 'ethereumjs-util';
-import * as _ from 'lodash';
 
 export const utils = {
-    /**
-     * Converts BigNumber instance to BN
-     * The only reason we convert to BN is to remain compatible with `ethABI. soliditySHA3` that
-     * expects values of Solidity type `uint` to be passed as type `BN`.
-     * We do not use BN anywhere else in the codebase.
-     */
-    bigNumberToBN(value: BigNumber) {
-        return new BN(value.toString(), 10);
-    },
     spawnSwitchErr(name: string, value: any): Error {
         return new Error(`Unexpected switch value: ${value} encountered for ${name}`);
     },
-    getOrderHashHex(order: Order | SignedOrder): string {
-        const orderParts = [
-            { value: order.exchangeContractAddress, type: SolidityTypes.Address },
-            { value: order.maker, type: SolidityTypes.Address },
-            { value: order.taker, type: SolidityTypes.Address },
-            { value: order.makerTokenAddress, type: SolidityTypes.Address },
-            { value: order.takerTokenAddress, type: SolidityTypes.Address },
-            { value: order.feeRecipient, type: SolidityTypes.Address },
-            {
-                value: utils.bigNumberToBN(order.makerTokenAmount),
-                type: SolidityTypes.Uint256,
-            },
-            {
-                value: utils.bigNumberToBN(order.takerTokenAmount),
-                type: SolidityTypes.Uint256,
-            },
-            {
-                value: utils.bigNumberToBN(order.makerFee),
-                type: SolidityTypes.Uint256,
-            },
-            {
-                value: utils.bigNumberToBN(order.takerFee),
-                type: SolidityTypes.Uint256,
-            },
-            {
-                value: utils.bigNumberToBN(order.expirationUnixTimestampSec),
-                type: SolidityTypes.Uint256,
-            },
-            { value: utils.bigNumberToBN(order.salt), type: SolidityTypes.Uint256 },
-        ];
-        const types = _.map(orderParts, o => o.type);
-        const values = _.map(orderParts, o => o.value);
-        const hashBuff = ethABI.soliditySHA3(types, values);
-        const hashHex = ethUtil.bufferToHex(hashBuff);
-        return hashHex;
-    },
     getCurrentUnixTimestampSec(): BigNumber {
         return new BigNumber(Date.now() / 1000).round();
     },
diff --git a/packages/0x.js/test/0x.js_test.ts b/packages/0x.js/test/0x.js_test.ts
index 838ee7080..6dccdaea7 100644
--- a/packages/0x.js/test/0x.js_test.ts
+++ b/packages/0x.js/test/0x.js_test.ts
@@ -17,8 +17,6 @@ const blockchainLifecycle = new BlockchainLifecycle(web3Wrapper);
 chaiSetup.configure();
 const expect = chai.expect;
 
-const SHOULD_ADD_PERSONAL_MESSAGE_PREFIX = false;
-
 describe('ZeroEx library', () => {
     let zeroEx: ZeroEx;
     before(async () => {
@@ -63,14 +61,12 @@ describe('ZeroEx library', () => {
         };
         const address = '0x5409ed021d9299bf6814279a6a1411a7e866a631';
         it("should return false if the data doesn't pertain to the signature & address", async () => {
-            expect(ZeroEx.isValidSignature('0x0', signature, address)).to.be.false();
             return expect(
                 (zeroEx.exchange as any)._isValidSignatureUsingContractCallAsync('0x0', signature, address),
             ).to.become(false);
         });
         it("should return false if the address doesn't pertain to the signature & data", async () => {
             const validUnrelatedAddress = '0x8b0292b11a196601ed2ce54b665cafeca0347d42';
-            expect(ZeroEx.isValidSignature(dataHex, signature, validUnrelatedAddress)).to.be.false();
             return expect(
                 (zeroEx.exchange as any)._isValidSignatureUsingContractCallAsync(
                     dataHex,
@@ -81,45 +77,16 @@ describe('ZeroEx library', () => {
         });
         it("should return false if the signature doesn't pertain to the dataHex & address", async () => {
             const wrongSignature = _.assign({}, signature, { v: 28 });
-            expect(ZeroEx.isValidSignature(dataHex, wrongSignature, address)).to.be.false();
             return expect(
                 (zeroEx.exchange as any)._isValidSignatureUsingContractCallAsync(dataHex, wrongSignature, address),
             ).to.become(false);
         });
         it('should return true if the signature does pertain to the dataHex & address', async () => {
-            const isValidSignatureLocal = ZeroEx.isValidSignature(dataHex, signature, address);
-            expect(isValidSignatureLocal).to.be.true();
             return expect(
                 (zeroEx.exchange as any)._isValidSignatureUsingContractCallAsync(dataHex, signature, address),
             ).to.become(true);
         });
     });
-    describe('#generateSalt', () => {
-        it('generates different salts', () => {
-            const equal = ZeroEx.generatePseudoRandomSalt().eq(ZeroEx.generatePseudoRandomSalt());
-            expect(equal).to.be.false();
-        });
-        it('generates salt in range [0..2^256)', () => {
-            const salt = ZeroEx.generatePseudoRandomSalt();
-            expect(salt.greaterThanOrEqualTo(0)).to.be.true();
-            const twoPow256 = new BigNumber(2).pow(256);
-            expect(salt.lessThan(twoPow256)).to.be.true();
-        });
-    });
-    describe('#isValidOrderHash', () => {
-        it('returns false if the value is not a hex string', () => {
-            const isValid = ZeroEx.isValidOrderHash('not a hex');
-            expect(isValid).to.be.false();
-        });
-        it('returns false if the length is wrong', () => {
-            const isValid = ZeroEx.isValidOrderHash('0xdeadbeef');
-            expect(isValid).to.be.false();
-        });
-        it('returns true if order hash is correct', () => {
-            const isValid = ZeroEx.isValidOrderHash('0x' + Array(65).join('0'));
-            expect(isValid).to.be.true();
-        });
-    });
     describe('#toUnitAmount', () => {
         it('should throw if invalid baseUnit amount supplied as argument', () => {
             const invalidBaseUnitAmount = new BigNumber(1000000000.4);
@@ -152,106 +119,6 @@ describe('ZeroEx library', () => {
             );
         });
     });
-    describe('#getOrderHashHex', () => {
-        const expectedOrderHash = '0x39da987067a3c9e5f1617694f1301326ba8c8b0498ebef5df4863bed394e3c83';
-        const fakeExchangeContractAddress = '0xb69e673309512a9d726f87304c6984054f87a93b';
-        const order: Order = {
-            maker: constants.NULL_ADDRESS,
-            taker: constants.NULL_ADDRESS,
-            feeRecipient: constants.NULL_ADDRESS,
-            makerTokenAddress: constants.NULL_ADDRESS,
-            takerTokenAddress: constants.NULL_ADDRESS,
-            exchangeContractAddress: fakeExchangeContractAddress,
-            salt: new BigNumber(0),
-            makerFee: new BigNumber(0),
-            takerFee: new BigNumber(0),
-            makerTokenAmount: new BigNumber(0),
-            takerTokenAmount: new BigNumber(0),
-            expirationUnixTimestampSec: new BigNumber(0),
-        };
-        it('calculates the order hash', async () => {
-            const orderHash = ZeroEx.getOrderHashHex(order);
-            expect(orderHash).to.be.equal(expectedOrderHash);
-        });
-        it('throws a readable error message if taker format is invalid', async () => {
-            const orderWithInvalidtakerFormat = {
-                ...order,
-                taker: (null as any) as string,
-            };
-            const expectedErrorMessage =
-                'Order taker must be of type string. If you want anyone to be able to fill an order - pass ZeroEx.NULL_ADDRESS';
-            expect(() => ZeroEx.getOrderHashHex(orderWithInvalidtakerFormat)).to.throw(expectedErrorMessage);
-        });
-    });
-    describe('#signOrderHashAsync', () => {
-        let stubs: Sinon.SinonStub[] = [];
-        let makerAddress: string;
-        before(async () => {
-            const availableAddreses = await zeroEx.getAvailableAddressesAsync();
-            makerAddress = availableAddreses[0];
-        });
-        afterEach(() => {
-            // clean up any stubs after the test has completed
-            _.each(stubs, s => s.restore());
-            stubs = [];
-        });
-        it('Should return the correct ECSignature', async () => {
-            const orderHash = '0x6927e990021d23b1eb7b8789f6a6feaf98fe104bb0cf8259421b79f9a34222b0';
-            const expectedECSignature = {
-                v: 27,
-                r: '0x61a3ed31b43c8780e905a260a35faefcc527be7516aa11c0256729b5b351bc33',
-                s: '0x40349190569279751135161d22529dc25add4f6069af05be04cacbda2ace2254',
-            };
-            const ecSignature = await zeroEx.signOrderHashAsync(
-                orderHash,
-                makerAddress,
-                SHOULD_ADD_PERSONAL_MESSAGE_PREFIX,
-            );
-            expect(ecSignature).to.deep.equal(expectedECSignature);
-        });
-        it('should return the correct ECSignature for signatureHex concatenated as R + S + V', async () => {
-            const orderHash = '0x34decbedc118904df65f379a175bb39ca18209d6ce41d5ed549d54e6e0a95004';
-            const signature =
-                '0x22109d11d79cb8bf96ed88625e1cd9558800c4073332a9a02857499883ee5ce3050aa3cc1f2c435e67e114cdce54b9527b4f50548342401bc5d2b77adbdacb021b';
-            const expectedECSignature = {
-                v: 27,
-                r: '0x22109d11d79cb8bf96ed88625e1cd9558800c4073332a9a02857499883ee5ce3',
-                s: '0x050aa3cc1f2c435e67e114cdce54b9527b4f50548342401bc5d2b77adbdacb02',
-            };
-            stubs = [
-                Sinon.stub((zeroEx as any)._web3Wrapper, 'signMessageAsync').returns(Promise.resolve(signature)),
-                Sinon.stub(ZeroEx, 'isValidSignature').returns(true),
-            ];
-
-            const ecSignature = await zeroEx.signOrderHashAsync(
-                orderHash,
-                makerAddress,
-                SHOULD_ADD_PERSONAL_MESSAGE_PREFIX,
-            );
-            expect(ecSignature).to.deep.equal(expectedECSignature);
-        });
-        it('should return the correct ECSignature for signatureHex concatenated as V + R + S', async () => {
-            const orderHash = '0xc793e33ffded933b76f2f48d9aa3339fc090399d5e7f5dec8d3660f5480793f7';
-            const signature =
-                '0x1bc80bedc6756722672753413efdd749b5adbd4fd552595f59c13427407ee9aee02dea66f25a608bbae457e020fb6decb763deb8b7192abab624997242da248960';
-            const expectedECSignature = {
-                v: 27,
-                r: '0xc80bedc6756722672753413efdd749b5adbd4fd552595f59c13427407ee9aee0',
-                s: '0x2dea66f25a608bbae457e020fb6decb763deb8b7192abab624997242da248960',
-            };
-            stubs = [
-                Sinon.stub((zeroEx as any)._web3Wrapper, 'signMessageAsync').returns(Promise.resolve(signature)),
-                Sinon.stub(ZeroEx, 'isValidSignature').returns(true),
-            ];
-
-            const ecSignature = await zeroEx.signOrderHashAsync(
-                orderHash,
-                makerAddress,
-                SHOULD_ADD_PERSONAL_MESSAGE_PREFIX,
-            );
-            expect(ecSignature).to.deep.equal(expectedECSignature);
-        });
-    });
     describe('#awaitTransactionMinedAsync', () => {
         beforeEach(async () => {
             await blockchainLifecycle.startAsync();
diff --git a/packages/0x.js/test/assert_test.ts b/packages/0x.js/test/assert_test.ts
index b08f3e23b..e69de29bb 100644
--- a/packages/0x.js/test/assert_test.ts
+++ b/packages/0x.js/test/assert_test.ts
@@ -1,43 +0,0 @@
-import { web3Factory } from '@0xproject/dev-utils';
-import * as chai from 'chai';
-import 'mocha';
-
-import { ZeroEx } from '../src';
-import { assert } from '../src/utils/assert';
-
-import { constants } from './utils/constants';
-import { provider } from './utils/web3_wrapper';
-
-const expect = chai.expect;
-
-describe('Assertion library', () => {
-    const config = {
-        networkId: constants.TESTRPC_NETWORK_ID,
-    };
-    const zeroEx = new ZeroEx(provider, config);
-    describe('#isSenderAddressHexAsync', () => {
-        it('throws when address is invalid', async () => {
-            const address = '0xdeadbeef';
-            const varName = 'address';
-            return expect(
-                assert.isSenderAddressAsync(varName, address, (zeroEx as any)._web3Wrapper),
-            ).to.be.rejectedWith(`Expected ${varName} to be of type ETHAddressHex, encountered: ${address}`);
-        });
-        it('throws when address is unavailable', async () => {
-            const validUnrelatedAddress = '0x8b0292b11a196601eddce54b665cafeca0347d42';
-            const varName = 'address';
-            return expect(
-                assert.isSenderAddressAsync(varName, validUnrelatedAddress, (zeroEx as any)._web3Wrapper),
-            ).to.be.rejectedWith(
-                `Specified ${varName} ${validUnrelatedAddress} isn't available through the supplied web3 provider`,
-            );
-        });
-        it("doesn't throw if address is available", async () => {
-            const availableAddress = (await zeroEx.getAvailableAddressesAsync())[0];
-            const varName = 'address';
-            return expect(
-                assert.isSenderAddressAsync(varName, availableAddress, (zeroEx as any)._web3Wrapper),
-            ).to.become(undefined);
-        });
-    });
-});
diff --git a/packages/0x.js/test/order_validation_test.ts b/packages/0x.js/test/order_validation_test.ts
index c894774b8..0cb95c1b6 100644
--- a/packages/0x.js/test/order_validation_test.ts
+++ b/packages/0x.js/test/order_validation_test.ts
@@ -1,4 +1,5 @@
 import { BlockchainLifecycle, devConstants } from '@0xproject/dev-utils';
+import { OrderError } from '@0xproject/order-utils';
 import { BlockParamLiteral } from '@0xproject/types';
 import { BigNumber } from '@0xproject/utils';
 import * as chai from 'chai';
@@ -68,6 +69,40 @@ describe('OrderValidation', () => {
             );
             await zeroEx.exchange.validateOrderFillableOrThrowAsync(signedOrder);
         });
+        it('should succeed if the maker is buying ZRX and has no ZRX balance', async () => {
+            const makerFee = new BigNumber(2);
+            const takerFee = new BigNumber(2);
+            const signedOrder = await fillScenarios.createFillableSignedOrderWithFeesAsync(
+                makerTokenAddress,
+                zrxTokenAddress,
+                makerFee,
+                takerFee,
+                makerAddress,
+                takerAddress,
+                fillableAmount,
+                feeRecipient,
+            );
+            const zrxMakerBalance = await zeroEx.token.getBalanceAsync(zrxTokenAddress, makerAddress);
+            await zeroEx.token.transferAsync(zrxTokenAddress, makerAddress, takerAddress, zrxMakerBalance);
+            await zeroEx.exchange.validateOrderFillableOrThrowAsync(signedOrder);
+        });
+        it('should succeed if the maker is buying ZRX and has no ZRX balance and there is no specified taker', async () => {
+            const makerFee = new BigNumber(2);
+            const takerFee = new BigNumber(2);
+            const signedOrder = await fillScenarios.createFillableSignedOrderWithFeesAsync(
+                makerTokenAddress,
+                zrxTokenAddress,
+                makerFee,
+                takerFee,
+                makerAddress,
+                constants.NULL_ADDRESS,
+                fillableAmount,
+                feeRecipient,
+            );
+            const zrxMakerBalance = await zeroEx.token.getBalanceAsync(zrxTokenAddress, makerAddress);
+            await zeroEx.token.transferAsync(zrxTokenAddress, makerAddress, takerAddress, zrxMakerBalance);
+            await zeroEx.exchange.validateOrderFillableOrThrowAsync(signedOrder);
+        });
         it('should succeed if the order is asymmetric and fillable', async () => {
             const makerFillableAmount = fillableAmount;
             const takerFillableAmount = fillableAmount.minus(4);
@@ -135,7 +170,7 @@ describe('OrderValidation', () => {
             signedOrder.ecSignature.v = 28 - signedOrder.ecSignature.v + 27;
             return expect(
                 zeroEx.exchange.validateFillOrderThrowIfInvalidAsync(signedOrder, fillableAmount, takerAddress),
-            ).to.be.rejectedWith(ZeroExError.InvalidSignature);
+            ).to.be.rejectedWith(OrderError.InvalidSignature);
         });
         it('should throw when the order is fully filled or cancelled', async () => {
             const signedOrder = await fillScenarios.createFillableSignedOrderAsync(
@@ -469,4 +504,4 @@ describe('OrderValidation', () => {
             expect(partialTakerFee).to.be.bignumber.equal(takerPartialFee);
         });
     });
-});
+}); // tslint:disable-line:max-file-line-count
diff --git a/packages/0x.js/test/utils/fill_scenarios.ts b/packages/0x.js/test/utils/fill_scenarios.ts
index 7d0e8c501..5a82a56d2 100644
--- a/packages/0x.js/test/utils/fill_scenarios.ts
+++ b/packages/0x.js/test/utils/fill_scenarios.ts
@@ -1,10 +1,10 @@
+import { orderFactory } from '@0xproject/order-utils';
 import { BigNumber } from '@0xproject/utils';
 import { Web3Wrapper } from '@0xproject/web3-wrapper';
 
 import { SignedOrder, Token, ZeroEx } from '../../src';
 import { artifacts } from '../../src/artifacts';
 import { DummyTokenContract } from '../../src/contract_wrappers/generated/dummy_token';
-import { orderFactory } from '../utils/order_factory';
 
 import { constants } from './constants';
 
@@ -164,7 +164,7 @@ export class FillScenarios {
         ]);
 
         const signedOrder = await orderFactory.createSignedOrderAsync(
-            this._zeroEx,
+            this._zeroEx.getProvider(),
             makerAddress,
             takerAddress,
             makerFee,
diff --git a/packages/0x.js/test/utils/order_factory.ts b/packages/0x.js/test/utils/order_factory.ts
deleted file mode 100644
index 08f2081a4..000000000
--- a/packages/0x.js/test/utils/order_factory.ts
+++ /dev/null
@@ -1,46 +0,0 @@
-import { BigNumber } from '@0xproject/utils';
-import * as _ from 'lodash';
-
-import { SignedOrder, ZeroEx } from '../../src';
-
-const SHOULD_ADD_PERSONAL_MESSAGE_PREFIX = false;
-
-export const orderFactory = {
-    async createSignedOrderAsync(
-        zeroEx: ZeroEx,
-        maker: string,
-        taker: string,
-        makerFee: BigNumber,
-        takerFee: BigNumber,
-        makerTokenAmount: BigNumber,
-        makerTokenAddress: string,
-        takerTokenAmount: BigNumber,
-        takerTokenAddress: string,
-        exchangeContractAddress: string,
-        feeRecipient: string,
-        expirationUnixTimestampSecIfExists?: BigNumber,
-    ): Promise<SignedOrder> {
-        const defaultExpirationUnixTimestampSec = new BigNumber(2524604400); // Close to infinite
-        const expirationUnixTimestampSec = _.isUndefined(expirationUnixTimestampSecIfExists)
-            ? defaultExpirationUnixTimestampSec
-            : expirationUnixTimestampSecIfExists;
-        const order = {
-            maker,
-            taker,
-            makerFee,
-            takerFee,
-            makerTokenAmount,
-            takerTokenAmount,
-            makerTokenAddress,
-            takerTokenAddress,
-            salt: ZeroEx.generatePseudoRandomSalt(),
-            exchangeContractAddress,
-            feeRecipient,
-            expirationUnixTimestampSec,
-        };
-        const orderHash = ZeroEx.getOrderHashHex(order);
-        const ecSignature = await zeroEx.signOrderHashAsync(orderHash, maker, SHOULD_ADD_PERSONAL_MESSAGE_PREFIX);
-        const signedOrder: SignedOrder = _.assign(order, { ecSignature });
-        return signedOrder;
-    },
-};
diff --git a/packages/0x.js/test/utils/web3_wrapper.ts b/packages/0x.js/test/utils/web3_wrapper.ts
index b7b3f0b7f..b0ccfa546 100644
--- a/packages/0x.js/test/utils/web3_wrapper.ts
+++ b/packages/0x.js/test/utils/web3_wrapper.ts
@@ -1,9 +1,6 @@
 import { devConstants, web3Factory } from '@0xproject/dev-utils';
 import { Provider } from '@0xproject/types';
 import { Web3Wrapper } from '@0xproject/web3-wrapper';
-import * as Web3 from 'web3';
-
-import { constants } from './constants';
 
 const web3 = web3Factory.create({ shouldUseInProcessGanache: true });
 const provider: Provider = web3.currentProvider;