Merge v2-prototype

8 files changed, 825 insertions, 825 deletions

diff --git a/packages/contracts/test/asset_proxy/proxies.ts b/packages/contracts/test/asset_proxy/proxies.ts
index 39674a030..62215f08d 100644
--- a/packages/contracts/test/asset_proxy/proxies.ts
+++ b/packages/contracts/test/asset_proxy/proxies.ts
@@ -1,17 +1,12 @@
 import { BlockchainLifecycle } from '@0xproject/dev-utils';
-import { assetDataUtils, generatePseudoRandomSalt } from '@0xproject/order-utils';
+import { assetDataUtils } from '@0xproject/order-utils';
 import { RevertReason } from '@0xproject/types';
 import { BigNumber } from '@0xproject/utils';
 import * as chai from 'chai';
-import { LogWithDecodedArgs } from 'ethereum-types';
-import ethUtil = require('ethereumjs-util');
 import * as _ from 'lodash';
 
 import { DummyERC20TokenContract } from '../../generated_contract_wrappers/dummy_erc20_token';
-import {
-    DummyERC721ReceiverContract,
-    DummyERC721ReceiverTokenReceivedEventArgs,
-} from '../../generated_contract_wrappers/dummy_erc721_receiver';
+import { DummyERC721ReceiverContract } from '../../generated_contract_wrappers/dummy_erc721_receiver';
 import { DummyERC721TokenContract } from '../../generated_contract_wrappers/dummy_erc721_token';
 import { ERC20ProxyContract } from '../../generated_contract_wrappers/erc20_proxy';
 import { ERC721ProxyContract } from '../../generated_contract_wrappers/erc721_proxy';
@@ -23,7 +18,6 @@ import { constants } from '../utils/constants';
 import { ERC20Wrapper } from '../utils/erc20_wrapper';
 import { ERC721Wrapper } from '../utils/erc721_wrapper';
 import { LogDecoder } from '../utils/log_decoder';
-import { typeEncodingUtils } from '../utils/type_encoding_utils';
 import { provider, txDefaults, web3Wrapper } from '../utils/web3_wrapper';
 
 chaiSetup.configure();
@@ -253,7 +247,7 @@ describe('Asset Transfer Proxies', () => {
                 expect(newOwnerMakerAsset).to.be.bignumber.equal(takerAddress);
             });
 
-            it('should call onERC721Received when transferring to a smart contract without receiver data', async () => {
+            it('should not call onERC721Received when transferring to a smart contract', async () => {
                 // Construct ERC721 asset data
                 const encodedAssetData = assetDataUtils.encodeERC721AssetData(erc721Token.address, erc721MakerTokenId);
                 // Verify pre-condition
@@ -277,85 +271,12 @@ describe('Asset Transfer Proxies', () => {
                     }),
                 );
                 // Verify that no log was emitted by erc721 receiver
-                expect(tx.logs.length).to.be.equal(1);
-                const tokenReceivedLog = tx.logs[0] as LogWithDecodedArgs<DummyERC721ReceiverTokenReceivedEventArgs>;
-                expect(tokenReceivedLog.args.from).to.be.equal(makerAddress);
-                expect(tokenReceivedLog.args.tokenId).to.be.bignumber.equal(erc721MakerTokenId);
-                expect(tokenReceivedLog.args.data).to.be.equal(constants.NULL_BYTES);
+                expect(tx.logs.length).to.be.equal(0);
                 // Verify transfer was successful
                 const newOwnerMakerAsset = await erc721Token.ownerOf.callAsync(erc721MakerTokenId);
                 expect(newOwnerMakerAsset).to.be.bignumber.equal(erc721Receiver.address);
             });
 
-            it('should call onERC721Received when transferring to a smart contract with receiver data', async () => {
-                // Construct ERC721 asset data
-                const receiverData = ethUtil.bufferToHex(typeEncodingUtils.encodeUint256(generatePseudoRandomSalt()));
-                const encodedAssetData = assetDataUtils.encodeERC721AssetData(
-                    erc721Token.address,
-                    erc721MakerTokenId,
-                    receiverData,
-                );
-                // Verify pre-condition
-                const ownerMakerAsset = await erc721Token.ownerOf.callAsync(erc721MakerTokenId);
-                expect(ownerMakerAsset).to.be.bignumber.equal(makerAddress);
-                // Perform a transfer from makerAddress to takerAddress
-                const amount = new BigNumber(1);
-                const data = assetProxyInterface.transferFrom.getABIEncodedTransactionData(
-                    encodedAssetData,
-                    makerAddress,
-                    erc721Receiver.address,
-                    amount,
-                );
-                const logDecoder = new LogDecoder(web3Wrapper, erc721Receiver.address);
-                const tx = await logDecoder.getTxWithDecodedLogsAsync(
-                    await web3Wrapper.sendTransactionAsync({
-                        to: erc721Proxy.address,
-                        data,
-                        from: exchangeAddress,
-                        gas: constants.MAX_TRANSFER_FROM_GAS,
-                    }),
-                );
-                // Validate log emitted by erc721 receiver
-                expect(tx.logs.length).to.be.equal(1);
-                const tokenReceivedLog = tx.logs[0] as LogWithDecodedArgs<DummyERC721ReceiverTokenReceivedEventArgs>;
-                expect(tokenReceivedLog.args.from).to.be.equal(makerAddress);
-                expect(tokenReceivedLog.args.tokenId).to.be.bignumber.equal(erc721MakerTokenId);
-                expect(tokenReceivedLog.args.data).to.be.equal(receiverData);
-                // Verify transfer was successful
-                const newOwnerMakerAsset = await erc721Token.ownerOf.callAsync(erc721MakerTokenId);
-                expect(newOwnerMakerAsset).to.be.bignumber.equal(erc721Receiver.address);
-            });
-
-            it('should throw if there is receiver data but contract does not have onERC721Received', async () => {
-                // Construct ERC721 asset data
-                const receiverData = ethUtil.bufferToHex(typeEncodingUtils.encodeUint256(generatePseudoRandomSalt()));
-                const encodedAssetData = assetDataUtils.encodeERC721AssetData(
-                    erc721Token.address,
-                    erc721MakerTokenId,
-                    receiverData,
-                );
-                // Verify pre-condition
-                const ownerMakerAsset = await erc721Token.ownerOf.callAsync(erc721MakerTokenId);
-                expect(ownerMakerAsset).to.be.bignumber.equal(makerAddress);
-                // Perform a transfer from makerAddress to takerAddress
-                const amount = new BigNumber(1);
-                const data = assetProxyInterface.transferFrom.getABIEncodedTransactionData(
-                    encodedAssetData,
-                    makerAddress,
-                    erc20Proxy.address, // the ERC20 proxy does not have an ERC721 receiver
-                    amount,
-                );
-                return expectTransactionFailedAsync(
-                    web3Wrapper.sendTransactionAsync({
-                        to: erc721Proxy.address,
-                        data,
-                        from: exchangeAddress,
-                        gas: constants.MAX_TRANSFER_FROM_GAS,
-                    }),
-                    RevertReason.TransferFailed,
-                );
-            });
-
             it('should throw if transferring 0 amount of a token', async () => {
                 // Construct ERC721 asset data
                 const encodedAssetData = assetDataUtils.encodeERC721AssetData(erc721Token.address, erc721MakerTokenId);
@@ -454,9 +375,9 @@ describe('Asset Transfer Proxies', () => {
             });
         });
 
-        it('should have an id of 0x08e937fa', async () => {
+        it('should have an id of 0x02571792', async () => {
             const proxyId = await erc721Proxy.getProxyId.callAsync();
-            const expectedProxyId = '0x08e937fa';
+            const expectedProxyId = '0x02571792';
             expect(proxyId).to.equal(expectedProxyId);
         });
     });
diff --git a/packages/contracts/test/exchange/core.ts b/packages/contracts/test/exchange/core.ts
index 33246a681..b324988cc 100644
--- a/packages/contracts/test/exchange/core.ts
+++ b/packages/contracts/test/exchange/core.ts
@@ -456,30 +456,6 @@ describe('Exchange core', () => {
                 RevertReason.RoundingError,
             );
         });
-
-        it('should throw if assetData has a length < 132', async () => {
-            // Construct Exchange parameters
-            const makerAssetId = erc721MakerAssetIds[0];
-            const takerAssetId = erc721TakerAssetIds[0];
-            const makerAssetData = assetDataUtils.encodeERC721AssetData(erc721Token.address, makerAssetId).slice(0, -2);
-            signedOrder = await orderFactory.newSignedOrderAsync({
-                makerAssetAmount: new BigNumber(1),
-                takerAssetAmount: new BigNumber(1),
-                makerAssetData,
-                takerAssetData: assetDataUtils.encodeERC721AssetData(erc721Token.address, takerAssetId),
-            });
-            // Verify pre-conditions
-            const initialOwnerMakerAsset = await erc721Token.ownerOf.callAsync(makerAssetId);
-            expect(initialOwnerMakerAsset).to.be.bignumber.equal(makerAddress);
-            const initialOwnerTakerAsset = await erc721Token.ownerOf.callAsync(takerAssetId);
-            expect(initialOwnerTakerAsset).to.be.bignumber.equal(takerAddress);
-            // Call Exchange
-            const takerAssetFillAmount = signedOrder.takerAssetAmount;
-            return expectTransactionFailedAsync(
-                exchangeWrapper.fillOrderAsync(signedOrder, takerAddress, { takerAssetFillAmount }),
-                RevertReason.LengthGreaterThan131Required,
-            );
-        });
     });
 
     describe('getOrderInfo', () => {
diff --git a/packages/contracts/test/exchange/libs.ts b/packages/contracts/test/exchange/libs.ts
index 2e95fa96c..51794d8a3 100644
--- a/packages/contracts/test/exchange/libs.ts
+++ b/packages/contracts/test/exchange/libs.ts
@@ -4,6 +4,7 @@ import { SignedOrder } from '@0xproject/types';
 import { BigNumber } from '@0xproject/utils';
 import * as chai from 'chai';
 
+import { TestConstantsContract } from '../../generated_contract_wrappers/test_constants';
 import { TestLibsContract } from '../../generated_contract_wrappers/test_libs';
 import { addressUtils } from '../utils/address_utils';
 import { artifacts } from '../utils/artifacts';
@@ -21,6 +22,7 @@ describe('Exchange libs', () => {
     let signedOrder: SignedOrder;
     let orderFactory: OrderFactory;
     let libs: TestLibsContract;
+    let testConstants: TestConstantsContract;
 
     before(async () => {
         await blockchainLifecycle.startAsync();
@@ -32,6 +34,11 @@ describe('Exchange libs', () => {
         const accounts = await web3Wrapper.getAvailableAddressesAsync();
         const makerAddress = accounts[0];
         libs = await TestLibsContract.deployFrom0xArtifactAsync(artifacts.TestLibs, provider, txDefaults);
+        testConstants = await TestConstantsContract.deployFrom0xArtifactAsync(
+            artifacts.TestConstants,
+            provider,
+            txDefaults,
+        );
 
         const defaultOrderParams = {
             ...constants.STATIC_ORDER_PARAMS,
@@ -52,6 +59,15 @@ describe('Exchange libs', () => {
         await blockchainLifecycle.revertAsync();
     });
 
+    describe('LibConstants', () => {
+        describe('ZRX_ASSET_DATA', () => {
+            it('should have the correct ZRX_ASSET_DATA', async () => {
+                const isValid = await testConstants.assertValidZrxAssetData.callAsync();
+                expect(isValid).to.be.equal(true);
+            });
+        });
+    });
+
     describe('LibOrder', () => {
         describe('getOrderSchema', () => {
             it('should output the correct order schema hash', async () => {
diff --git a/packages/contracts/test/exchange/signature_validator.ts b/packages/contracts/test/exchange/signature_validator.ts
index ef154bf9b..f2bb42c75 100644
--- a/packages/contracts/test/exchange/signature_validator.ts
+++ b/packages/contracts/test/exchange/signature_validator.ts
@@ -9,8 +9,8 @@ import {
     TestSignatureValidatorContract,
     TestSignatureValidatorSignatureValidatorApprovalEventArgs,
 } from '../../generated_contract_wrappers/test_signature_validator';
-import { TestValidatorContract } from '../../generated_contract_wrappers/test_validator';
-import { TestWalletContract } from '../../generated_contract_wrappers/test_wallet';
+import { ValidatorContract } from '../../generated_contract_wrappers/validator';
+import { WalletContract } from '../../generated_contract_wrappers/wallet';
 import { addressUtils } from '../utils/address_utils';
 import { artifacts } from '../utils/artifacts';
 import { expectContractCallFailed } from '../utils/assertions';
@@ -29,8 +29,8 @@ describe('MixinSignatureValidator', () => {
     let signedOrder: SignedOrder;
     let orderFactory: OrderFactory;
     let signatureValidator: TestSignatureValidatorContract;
-    let testWallet: TestWalletContract;
-    let testValidator: TestValidatorContract;
+    let testWallet: WalletContract;
+    let testValidator: ValidatorContract;
     let signerAddress: string;
     let signerPrivateKey: Buffer;
     let notSignerAddress: string;
@@ -53,14 +53,14 @@ describe('MixinSignatureValidator', () => {
             provider,
             txDefaults,
         );
-        testWallet = await TestWalletContract.deployFrom0xArtifactAsync(
-            artifacts.TestWallet,
+        testWallet = await WalletContract.deployFrom0xArtifactAsync(
+            artifacts.Wallet,
             provider,
             txDefaults,
             signerAddress,
         );
-        testValidator = await TestValidatorContract.deployFrom0xArtifactAsync(
-            artifacts.TestValidator,
+        testValidator = await ValidatorContract.deployFrom0xArtifactAsync(
+            artifacts.Validator,
             provider,
             txDefaults,
             signerAddress,
diff --git a/packages/contracts/test/forwarder/forwarder.ts b/packages/contracts/test/forwarder/forwarder.ts
index 0256d7d81..19639d3aa 100644
--- a/packages/contracts/test/forwarder/forwarder.ts
+++ b/packages/contracts/test/forwarder/forwarder.ts
@@ -18,7 +18,6 @@ import { constants } from '../utils/constants';
 import { ERC20Wrapper } from '../utils/erc20_wrapper';
 import { ERC721Wrapper } from '../utils/erc721_wrapper';
 import { ExchangeWrapper } from '../utils/exchange_wrapper';
-import { formatters } from '../utils/formatters';
 import { ForwarderWrapper } from '../utils/forwarder_wrapper';
 import { OrderFactory } from '../utils/order_factory';
 import { ContractName, ERC20BalancesByOwner } from '../utils/types';
@@ -28,8 +27,7 @@ chaiSetup.configure();
 const expect = chai.expect;
 const blockchainLifecycle = new BlockchainLifecycle(web3Wrapper);
 const DECIMALS_DEFAULT = 18;
-// Set a gasPrice so when checking balance of msg.sender we can accurately calculate gasPrice*gasUsed
-const DEFAULT_GAS_PRICE = new BigNumber(1);
+const MAX_WETH_FILL_PERCENTAGE = 95;
 
 describe(ContractName.Forwarder, () => {
     let makerAddress: string;
@@ -47,25 +45,28 @@ describe(ContractName.Forwarder, () => {
     let forwarderWrapper: ForwarderWrapper;
     let exchangeWrapper: ExchangeWrapper;
 
-    let signedOrder: SignedOrder;
-    let signedOrders: SignedOrder[];
+    let orderWithoutFee: SignedOrder;
     let orderWithFee: SignedOrder;
-    let signedOrdersWithFee: SignedOrder[];
     let feeOrder: SignedOrder;
-    let feeOrders: SignedOrder[];
     let orderFactory: OrderFactory;
     let erc20Wrapper: ERC20Wrapper;
     let erc20Balances: ERC20BalancesByOwner;
     let tx: TransactionReceiptWithDecodedLogs;
 
     let erc721MakerAssetIds: BigNumber[];
-    let feeProportion: number = 0;
+    let takerEthBalanceBefore: BigNumber;
+    let feePercentage: BigNumber;
+    let gasPrice: BigNumber;
 
     before(async () => {
         await blockchainLifecycle.startAsync();
         const accounts = await web3Wrapper.getAvailableAddressesAsync();
         const usedAddresses = ([owner, makerAddress, takerAddress, feeRecipientAddress, otherAddress] = accounts);
 
+        const txHash = await web3Wrapper.sendTransactionAsync({ from: accounts[0], to: accounts[0], value: 0 });
+        const transaction = await web3Wrapper.getTransactionByHashAsync(txHash);
+        gasPrice = new BigNumber(transaction.gasPrice);
+
         const erc721Wrapper = new ERC721Wrapper(provider, usedAddresses, owner);
         erc20Wrapper = new ERC20Wrapper(provider, usedAddresses, owner);
 
@@ -135,681 +136,865 @@ describe(ContractName.Forwarder, () => {
             wethAssetData,
         );
         forwarderContract = new ForwarderContract(forwarderInstance.abi, forwarderInstance.address, provider);
-        forwarderWrapper = new ForwarderWrapper(forwarderContract, provider, zrxToken.address);
+        forwarderWrapper = new ForwarderWrapper(forwarderContract, provider);
+        const zrxDepositAmount = Web3Wrapper.toBaseUnitAmount(new BigNumber(10000), 18);
+        await web3Wrapper.awaitTransactionSuccessAsync(
+            await zrxToken.transfer.sendTransactionAsync(forwarderContract.address, zrxDepositAmount),
+        );
         erc20Wrapper.addTokenOwnerAddress(forwarderInstance.address);
-
-        web3Wrapper.abiDecoder.addABI(forwarderContract.abi);
-        web3Wrapper.abiDecoder.addABI(exchangeInstance.abi);
     });
     after(async () => {
         await blockchainLifecycle.revertAsync();
     });
     beforeEach(async () => {
         await blockchainLifecycle.startAsync();
-        feeProportion = 0;
         erc20Balances = await erc20Wrapper.getBalancesAsync();
-        signedOrder = await orderFactory.newSignedOrderAsync();
-        signedOrders = [signedOrder];
+        takerEthBalanceBefore = await web3Wrapper.getBalanceInWeiAsync(takerAddress);
+        orderWithoutFee = await orderFactory.newSignedOrderAsync();
         feeOrder = await orderFactory.newSignedOrderAsync({
             makerAssetData: assetDataUtils.encodeERC20AssetData(zrxToken.address),
             takerFee: Web3Wrapper.toBaseUnitAmount(new BigNumber(1), DECIMALS_DEFAULT),
         });
-        feeOrders = [feeOrder];
         orderWithFee = await orderFactory.newSignedOrderAsync({
             takerFee: Web3Wrapper.toBaseUnitAmount(new BigNumber(1), DECIMALS_DEFAULT),
         });
-        signedOrdersWithFee = [orderWithFee];
     });
     afterEach(async () => {
         await blockchainLifecycle.revertAsync();
     });
-    describe('calculations', () => {
-        it('throws if partially filled orders passed in are not enough to satisfy requested amount', async () => {
-            feeOrders = [feeOrder];
-            const makerTokenFillAmount = feeOrder.makerAssetAmount.div(2);
-            const fillAmountWei = await forwarderWrapper.calculateMarketBuyFillAmountWeiAsync(
-                feeOrders,
-                [],
-                feeProportion,
-                makerTokenFillAmount,
-            );
-            // Fill the feeOrder
-            tx = await forwarderWrapper.marketBuyTokensWithEthAsync(feeOrders, [], makerTokenFillAmount, {
+
+    describe('marketSellOrdersWithEth without extra fees', () => {
+        it('should fill a single order', async () => {
+            const ordersWithoutFee = [orderWithoutFee];
+            const feeOrders: SignedOrder[] = [];
+            const ethValue = orderWithoutFee.takerAssetAmount.dividedToIntegerBy(2);
+
+            tx = await forwarderWrapper.marketSellOrdersWithEthAsync(ordersWithoutFee, feeOrders, {
+                value: ethValue,
                 from: takerAddress,
-                value: fillAmountWei,
             });
-            return expect(
-                forwarderWrapper.calculateMarketBuyFillAmountWeiAsync(
-                    feeOrders,
-                    [],
-                    feeProportion,
-                    makerTokenFillAmount,
-                ),
-            ).to.be.rejectedWith('Unable to satisfy makerAssetFillAmount with provided orders');
+            const takerEthBalanceAfter = await web3Wrapper.getBalanceInWeiAsync(takerAddress);
+            const forwarderEthBalance = await web3Wrapper.getBalanceInWeiAsync(forwarderContract.address);
+            const newBalances = await erc20Wrapper.getBalancesAsync();
+
+            const primaryTakerAssetFillAmount = ForwarderWrapper.getPercentageOfValue(
+                ethValue,
+                MAX_WETH_FILL_PERCENTAGE,
+            );
+            const makerAssetFillAmount = primaryTakerAssetFillAmount
+                .times(orderWithoutFee.makerAssetAmount)
+                .dividedToIntegerBy(orderWithoutFee.takerAssetAmount);
+            const totalEthSpent = primaryTakerAssetFillAmount.plus(gasPrice.times(tx.gasUsed));
+
+            expect(takerEthBalanceAfter).to.be.bignumber.equal(takerEthBalanceBefore.minus(totalEthSpent));
+            expect(newBalances[makerAddress][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[makerAddress][defaultMakerAssetAddress].minus(makerAssetFillAmount),
+            );
+            expect(newBalances[takerAddress][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[takerAddress][defaultMakerAssetAddress].plus(makerAssetFillAmount),
+            );
+            expect(newBalances[makerAddress][weth.address]).to.be.bignumber.equal(
+                erc20Balances[makerAddress][weth.address].plus(primaryTakerAssetFillAmount),
+            );
+            expect(newBalances[forwarderContract.address][weth.address]).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(newBalances[forwarderContract.address][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                constants.ZERO_AMOUNT,
+            );
+            expect(forwarderEthBalance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
         });
-        it('throws if orders passed are cancelled', async () => {
-            tx = await exchangeWrapper.cancelOrderAsync(feeOrder, makerAddress);
-            // Cancel the feeOrder
-            return expect(
-                forwarderWrapper.calculateMarketBuyFillAmountWeiAsync(
-                    feeOrders,
-                    [],
-                    feeProportion,
-                    feeOrder.makerAssetAmount.div(2),
-                ),
-            ).to.be.rejectedWith('Unable to satisfy makerAssetFillAmount with provided orders');
+        it('should fill multiple orders', async () => {
+            const secondOrderWithoutFee = await orderFactory.newSignedOrderAsync();
+            const ordersWithoutFee = [orderWithoutFee, secondOrderWithoutFee];
+            const feeOrders: SignedOrder[] = [];
+            const ethValue = ordersWithoutFee[0].takerAssetAmount.plus(
+                ordersWithoutFee[1].takerAssetAmount.dividedToIntegerBy(2),
+            );
+
+            tx = await forwarderWrapper.marketSellOrdersWithEthAsync(ordersWithoutFee, feeOrders, {
+                value: ethValue,
+                from: takerAddress,
+            });
+            const takerEthBalanceAfter = await web3Wrapper.getBalanceInWeiAsync(takerAddress);
+            const forwarderEthBalance = await web3Wrapper.getBalanceInWeiAsync(forwarderContract.address);
+            const newBalances = await erc20Wrapper.getBalancesAsync();
+
+            const primaryTakerAssetFillAmount = ForwarderWrapper.getPercentageOfValue(
+                ethValue,
+                MAX_WETH_FILL_PERCENTAGE,
+            );
+            const firstTakerAssetFillAmount = ordersWithoutFee[0].takerAssetAmount;
+            const secondTakerAssetFillAmount = primaryTakerAssetFillAmount.minus(firstTakerAssetFillAmount);
+
+            const makerAssetFillAmount = ordersWithoutFee[0].makerAssetAmount.plus(
+                ordersWithoutFee[1].makerAssetAmount
+                    .times(secondTakerAssetFillAmount)
+                    .dividedToIntegerBy(ordersWithoutFee[1].takerAssetAmount),
+            );
+            const totalEthSpent = primaryTakerAssetFillAmount.plus(gasPrice.times(tx.gasUsed));
+            expect(takerEthBalanceAfter).to.be.bignumber.equal(takerEthBalanceBefore.minus(totalEthSpent));
+            expect(newBalances[makerAddress][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[makerAddress][defaultMakerAssetAddress].minus(makerAssetFillAmount),
+            );
+            expect(newBalances[takerAddress][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[takerAddress][defaultMakerAssetAddress].plus(makerAssetFillAmount),
+            );
+            expect(newBalances[makerAddress][weth.address]).to.be.bignumber.equal(
+                erc20Balances[makerAddress][weth.address].plus(primaryTakerAssetFillAmount),
+            );
+            expect(newBalances[forwarderContract.address][weth.address]).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(newBalances[forwarderContract.address][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                constants.ZERO_AMOUNT,
+            );
+            expect(forwarderEthBalance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
         });
-    });
-    describe('marketSellEthForERC20 without extra fees', () => {
-        it('should fill the order', async () => {
-            const fillAmount = signedOrder.takerAssetAmount.div(2);
-            const makerBalanceBefore = erc20Balances[makerAddress][defaultMakerAssetAddress];
-            const takerBalanceBefore = erc20Balances[takerAddress][defaultMakerAssetAddress];
-            feeOrders = [];
-            tx = await forwarderWrapper.marketSellEthForERC20Async(signedOrders, feeOrders, {
-                value: fillAmount,
+        it('should fill the order and pay ZRX fees from a single feeOrder', async () => {
+            const ordersWithFee = [orderWithFee];
+            const feeOrders = [feeOrder];
+            const ethValue = orderWithFee.takerAssetAmount.dividedToIntegerBy(2);
+
+            tx = await forwarderWrapper.marketSellOrdersWithEthAsync(ordersWithFee, feeOrders, {
+                value: ethValue,
                 from: takerAddress,
             });
+            const takerEthBalanceAfter = await web3Wrapper.getBalanceInWeiAsync(takerAddress);
+            const forwarderEthBalance = await web3Wrapper.getBalanceInWeiAsync(forwarderContract.address);
             const newBalances = await erc20Wrapper.getBalancesAsync();
-            const makerBalanceAfter = newBalances[makerAddress][defaultMakerAssetAddress];
-            const takerBalanceAfter = newBalances[takerAddress][defaultMakerAssetAddress];
-            const makerTokenFillAmount = fillAmount
-                .times(signedOrder.makerAssetAmount)
-                .dividedToIntegerBy(signedOrder.takerAssetAmount);
-
-            expect(makerBalanceAfter).to.be.bignumber.equal(makerBalanceBefore.minus(makerTokenFillAmount));
-            expect(takerBalanceAfter).to.be.bignumber.equal(takerBalanceBefore.plus(makerTokenFillAmount));
-            expect(newBalances[forwarderContract.address][weth.address]).to.be.bignumber.equal(new BigNumber(0));
+
+            const primaryTakerAssetFillAmount = ForwarderWrapper.getPercentageOfValue(
+                ethValue,
+                MAX_WETH_FILL_PERCENTAGE,
+            );
+            const makerAssetFillAmount = primaryTakerAssetFillAmount
+                .times(orderWithoutFee.makerAssetAmount)
+                .dividedToIntegerBy(orderWithoutFee.takerAssetAmount);
+            const feeAmount = ForwarderWrapper.getPercentageOfValue(
+                orderWithFee.takerFee.dividedToIntegerBy(2),
+                MAX_WETH_FILL_PERCENTAGE,
+            );
+            const wethSpentOnFeeOrders = ForwarderWrapper.getWethForFeeOrders(feeAmount, feeOrders);
+            const totalEthSpent = primaryTakerAssetFillAmount
+                .plus(wethSpentOnFeeOrders)
+                .plus(gasPrice.times(tx.gasUsed));
+
+            expect(takerEthBalanceAfter).to.be.bignumber.equal(takerEthBalanceBefore.minus(totalEthSpent));
+            expect(newBalances[makerAddress][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[makerAddress][defaultMakerAssetAddress].minus(makerAssetFillAmount),
+            );
+            expect(newBalances[takerAddress][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[takerAddress][defaultMakerAssetAddress].plus(makerAssetFillAmount),
+            );
+            expect(newBalances[makerAddress][weth.address]).to.be.bignumber.equal(
+                erc20Balances[makerAddress][weth.address].plus(primaryTakerAssetFillAmount).plus(wethSpentOnFeeOrders),
+            );
+            expect(newBalances[forwarderContract.address][weth.address]).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(newBalances[forwarderContract.address][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                constants.ZERO_AMOUNT,
+            );
+            expect(forwarderEthBalance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
         });
-        it('should fill the order and perform fee abstraction', async () => {
-            const fillAmount = signedOrder.takerAssetAmount.div(4);
-            const takerBalanceBefore = erc20Balances[takerAddress][defaultMakerAssetAddress];
-            tx = await forwarderWrapper.marketSellEthForERC20Async(signedOrdersWithFee, feeOrders, {
-                value: fillAmount,
+        it('should fill the orders and pay ZRX from multiple feeOrders', async () => {
+            const ordersWithFee = [orderWithFee];
+            const ethValue = orderWithFee.takerAssetAmount;
+            const makerAssetData = assetDataUtils.encodeERC20AssetData(zrxToken.address);
+            const makerAssetAmount = orderWithFee.takerFee.dividedToIntegerBy(2);
+            const takerAssetAmount = feeOrder.takerAssetAmount
+                .times(makerAssetAmount)
+                .dividedToIntegerBy(feeOrder.makerAssetAmount);
+
+            const firstFeeOrder = await orderFactory.newSignedOrderAsync({
+                makerAssetData,
+                makerAssetAmount,
+                takerAssetAmount,
+            });
+            const secondFeeOrder = await orderFactory.newSignedOrderAsync({
+                makerAssetData,
+                makerAssetAmount,
+                takerAssetAmount,
+            });
+            const feeOrders = [firstFeeOrder, secondFeeOrder];
+
+            tx = await forwarderWrapper.marketSellOrdersWithEthAsync(ordersWithFee, feeOrders, {
+                value: ethValue,
                 from: takerAddress,
             });
+            const takerEthBalanceAfter = await web3Wrapper.getBalanceInWeiAsync(takerAddress);
+            const forwarderEthBalance = await web3Wrapper.getBalanceInWeiAsync(forwarderContract.address);
             const newBalances = await erc20Wrapper.getBalancesAsync();
-            const takerBalanceAfter = newBalances[takerAddress][defaultMakerAssetAddress];
 
-            const acceptPercentage = 98;
-            const acceptableThreshold = takerBalanceBefore.plus(fillAmount.times(acceptPercentage).dividedBy(100));
-            const isWithinThreshold = takerBalanceAfter.greaterThanOrEqualTo(acceptableThreshold);
-            expect(isWithinThreshold).to.be.true();
-            expect(newBalances[forwarderContract.address][weth.address]).to.be.bignumber.equal(new BigNumber(0));
+            const primaryTakerAssetFillAmount = ForwarderWrapper.getPercentageOfValue(
+                ethValue,
+                MAX_WETH_FILL_PERCENTAGE,
+            );
+            const makerAssetFillAmount = primaryTakerAssetFillAmount
+                .times(orderWithoutFee.makerAssetAmount)
+                .dividedToIntegerBy(orderWithoutFee.takerAssetAmount);
+            const feeAmount = ForwarderWrapper.getPercentageOfValue(orderWithFee.takerFee, MAX_WETH_FILL_PERCENTAGE);
+            const wethSpentOnFeeOrders = ForwarderWrapper.getWethForFeeOrders(feeAmount, feeOrders);
+            const totalEthSpent = primaryTakerAssetFillAmount
+                .plus(wethSpentOnFeeOrders)
+                .plus(gasPrice.times(tx.gasUsed));
+
+            expect(takerEthBalanceAfter).to.be.bignumber.equal(takerEthBalanceBefore.minus(totalEthSpent));
+            expect(newBalances[makerAddress][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[makerAddress][defaultMakerAssetAddress].minus(makerAssetFillAmount),
+            );
+            expect(newBalances[takerAddress][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[takerAddress][defaultMakerAssetAddress].plus(makerAssetFillAmount),
+            );
+            expect(newBalances[makerAddress][weth.address]).to.be.bignumber.equal(
+                erc20Balances[makerAddress][weth.address].plus(primaryTakerAssetFillAmount).plus(wethSpentOnFeeOrders),
+            );
+            expect(newBalances[forwarderContract.address][weth.address]).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(newBalances[forwarderContract.address][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                constants.ZERO_AMOUNT,
+            );
+            expect(forwarderEthBalance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
         });
         it('should fill the order when token is ZRX with fees', async () => {
             orderWithFee = await orderFactory.newSignedOrderAsync({
                 makerAssetData: assetDataUtils.encodeERC20AssetData(zrxToken.address),
                 takerFee: Web3Wrapper.toBaseUnitAmount(new BigNumber(1), DECIMALS_DEFAULT),
             });
-            signedOrdersWithFee = [orderWithFee];
-            feeOrders = [];
-            const fillAmount = signedOrder.takerAssetAmount.div(4);
-            const takerBalanceBefore = erc20Balances[takerAddress][zrxToken.address];
-            tx = await forwarderWrapper.marketSellEthForERC20Async(signedOrdersWithFee, feeOrders, {
-                value: fillAmount,
+            const ordersWithFee = [orderWithFee];
+            const feeOrders: SignedOrder[] = [];
+            const ethValue = orderWithFee.takerAssetAmount.dividedToIntegerBy(2);
+
+            tx = await forwarderWrapper.marketSellOrdersWithEthAsync(ordersWithFee, feeOrders, {
+                value: ethValue,
                 from: takerAddress,
             });
+            const takerEthBalanceAfter = await web3Wrapper.getBalanceInWeiAsync(takerAddress);
+            const forwarderEthBalance = await web3Wrapper.getBalanceInWeiAsync(forwarderContract.address);
             const newBalances = await erc20Wrapper.getBalancesAsync();
-            const takerBalanceAfter = newBalances[takerAddress][zrxToken.address];
 
-            const acceptPercentage = 98;
-            const acceptableThreshold = takerBalanceBefore.plus(fillAmount.times(acceptPercentage).dividedBy(100));
-            const isWithinThreshold = takerBalanceAfter.greaterThanOrEqualTo(acceptableThreshold);
-            expect(isWithinThreshold).to.be.true();
-            expect(newBalances[forwarderContract.address][weth.address]).to.be.bignumber.equal(new BigNumber(0));
+            const makerAssetFillAmount = orderWithFee.makerAssetAmount.dividedToIntegerBy(2);
+            const totalEthSpent = ethValue.plus(gasPrice.times(tx.gasUsed));
+            const takerFeePaid = orderWithFee.takerFee.dividedToIntegerBy(2);
+            const makerFeePaid = orderWithFee.makerFee.dividedToIntegerBy(2);
+
+            expect(takerEthBalanceAfter).to.be.bignumber.equal(takerEthBalanceBefore.minus(totalEthSpent));
+            expect(newBalances[makerAddress][zrxToken.address]).to.be.bignumber.equal(
+                erc20Balances[makerAddress][zrxToken.address].minus(makerAssetFillAmount).minus(makerFeePaid),
+            );
+            expect(newBalances[takerAddress][zrxToken.address]).to.be.bignumber.equal(
+                erc20Balances[takerAddress][zrxToken.address].plus(makerAssetFillAmount).minus(takerFeePaid),
+            );
+            expect(newBalances[makerAddress][weth.address]).to.be.bignumber.equal(
+                erc20Balances[makerAddress][weth.address].plus(ethValue),
+            );
+            expect(newBalances[forwarderContract.address][weth.address]).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(newBalances[forwarderContract.address][zrxToken.address]).to.be.bignumber.equal(
+                erc20Balances[forwarderContract.address][zrxToken.address],
+            );
+            expect(forwarderEthBalance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
         });
-        it('should fail if sent an ETH amount too high', async () => {
-            signedOrder = await orderFactory.newSignedOrderAsync({
-                makerAssetData: assetDataUtils.encodeERC20AssetData(zrxToken.address),
-                takerFee: Web3Wrapper.toBaseUnitAmount(new BigNumber(1), DECIMALS_DEFAULT),
+        it('should refund remaining ETH if amount is greater than takerAssetAmount', async () => {
+            const ordersWithoutFee = [orderWithoutFee];
+            const feeOrders: SignedOrder[] = [];
+            const ethValue = orderWithoutFee.takerAssetAmount.times(2);
+
+            tx = await forwarderWrapper.marketSellOrdersWithEthAsync(ordersWithoutFee, feeOrders, {
+                value: ethValue,
+                from: takerAddress,
             });
-            const fillAmount = signedOrder.takerAssetAmount.times(2);
-            return expectTransactionFailedAsync(
-                forwarderWrapper.marketSellEthForERC20Async(signedOrdersWithFee, feeOrders, {
-                    value: fillAmount,
-                    from: takerAddress,
-                }),
-                RevertReason.UnacceptableThreshold,
-            );
+            const takerEthBalanceAfter = await web3Wrapper.getBalanceInWeiAsync(takerAddress);
+            const totalEthSpent = orderWithoutFee.takerAssetAmount.plus(gasPrice.times(tx.gasUsed));
+
+            expect(takerEthBalanceAfter).to.be.bignumber.equal(takerEthBalanceBefore.minus(totalEthSpent));
         });
-        it('should fail if fee abstraction amount is too high', async () => {
+        it('should revert if ZRX cannot be fully repurchased', async () => {
             orderWithFee = await orderFactory.newSignedOrderAsync({
                 takerFee: Web3Wrapper.toBaseUnitAmount(new BigNumber(50), DECIMALS_DEFAULT),
             });
-            signedOrdersWithFee = [orderWithFee];
+            const ordersWithFee = [orderWithFee];
             feeOrder = await orderFactory.newSignedOrderAsync({
                 makerAssetData: assetDataUtils.encodeERC20AssetData(zrxToken.address),
                 makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(1), DECIMALS_DEFAULT),
             });
-            feeOrders = [feeOrder];
-            const fillAmount = signedOrder.takerAssetAmount.div(4);
+            const feeOrders = [feeOrder];
+            const ethValue = orderWithFee.takerAssetAmount;
             return expectTransactionFailedAsync(
-                forwarderWrapper.marketSellEthForERC20Async(signedOrdersWithFee, feeOrders, {
-                    value: fillAmount,
+                forwarderWrapper.marketSellOrdersWithEthAsync(ordersWithFee, feeOrders, {
+                    value: ethValue,
                     from: takerAddress,
                 }),
-                RevertReason.TransferFailed,
+                RevertReason.CompleteFillFailed,
             );
         });
-        it('throws when mixed ERC721 and ERC20 assets with ERC20 first', async () => {
+        it('should not fill orders with different makerAssetData than the first order', async () => {
             const makerAssetId = erc721MakerAssetIds[0];
             const erc721SignedOrder = await orderFactory.newSignedOrderAsync({
                 makerAssetAmount: new BigNumber(1),
                 makerAssetData: assetDataUtils.encodeERC721AssetData(erc721Token.address, makerAssetId),
             });
             const erc20SignedOrder = await orderFactory.newSignedOrderAsync();
-            signedOrders = [erc20SignedOrder, erc721SignedOrder];
-            const fillAmountWei = erc20SignedOrder.takerAssetAmount.plus(erc721SignedOrder.takerAssetAmount);
-            return expectTransactionFailedAsync(
-                forwarderWrapper.marketSellEthForERC20Async(signedOrders, feeOrders, {
-                    from: takerAddress,
-                    value: fillAmountWei,
-                }),
-                RevertReason.InvalidOrderSignature,
-            );
+            const ordersWithoutFee = [erc20SignedOrder, erc721SignedOrder];
+            const feeOrders: SignedOrder[] = [];
+            const ethValue = erc20SignedOrder.takerAssetAmount.plus(erc721SignedOrder.takerAssetAmount);
+
+            tx = await forwarderWrapper.marketSellOrdersWithEthAsync(ordersWithoutFee, feeOrders, {
+                value: ethValue,
+                from: takerAddress,
+            });
+            const takerEthBalanceAfter = await web3Wrapper.getBalanceInWeiAsync(takerAddress);
+            const totalEthSpent = erc20SignedOrder.takerAssetAmount.plus(gasPrice.times(tx.gasUsed));
+
+            expect(takerEthBalanceAfter).to.be.bignumber.equal(takerEthBalanceBefore.minus(totalEthSpent));
         });
     });
-    describe('marketSellEthForERC20 with extra fees', () => {
-        it('should fill the order and send fee to fee recipient', async () => {
-            const initEthBalance = await web3Wrapper.getBalanceInWeiAsync(feeRecipientAddress);
-            const fillAmount = signedOrder.takerAssetAmount.div(2);
-            feeProportion = 150; // 1.5%
-            feeOrders = [];
-            tx = await forwarderWrapper.marketSellEthForERC20Async(
-                signedOrders,
+    describe('marketSellOrdersWithEth with extra fees', () => {
+        it('should fill the order and send fee to feeRecipient', async () => {
+            const ordersWithoutFee = [orderWithoutFee];
+            const feeOrders: SignedOrder[] = [];
+            const ethValue = orderWithoutFee.takerAssetAmount.div(2);
+
+            const baseFeePercentage = 2;
+            feePercentage = ForwarderWrapper.getPercentageOfValue(constants.PERCENTAGE_DENOMINATOR, baseFeePercentage);
+            const feeRecipientEthBalanceBefore = await web3Wrapper.getBalanceInWeiAsync(feeRecipientAddress);
+            tx = await forwarderWrapper.marketSellOrdersWithEthAsync(
+                ordersWithoutFee,
                 feeOrders,
                 {
+                    value: ethValue,
                     from: takerAddress,
-                    value: fillAmount,
-                    gasPrice: DEFAULT_GAS_PRICE,
-                },
-                {
-                    feeProportion,
-                    feeRecipient: feeRecipientAddress,
                 },
+                { feePercentage, feeRecipient: feeRecipientAddress },
             );
+            const takerEthBalanceAfter = await web3Wrapper.getBalanceInWeiAsync(takerAddress);
+            const feeRecipientEthBalanceAfter = await web3Wrapper.getBalanceInWeiAsync(feeRecipientAddress);
+            const forwarderEthBalance = await web3Wrapper.getBalanceInWeiAsync(forwarderContract.address);
             const newBalances = await erc20Wrapper.getBalancesAsync();
-            const makerBalanceBefore = erc20Balances[makerAddress][defaultMakerAssetAddress];
-            const makerBalanceAfter = newBalances[makerAddress][defaultMakerAssetAddress];
-            const takerBalanceAfter = newBalances[takerAddress][defaultMakerAssetAddress];
-            const afterEthBalance = await web3Wrapper.getBalanceInWeiAsync(feeRecipientAddress);
-            const takerBoughtAmount = takerBalanceAfter.minus(erc20Balances[takerAddress][defaultMakerAssetAddress]);
 
-            expect(makerBalanceAfter).to.be.bignumber.equal(makerBalanceBefore.minus(takerBoughtAmount));
-            expect(afterEthBalance).to.be.bignumber.equal(
-                initEthBalance.plus(fillAmount.times(feeProportion).dividedBy(10000)),
+            const primaryTakerAssetFillAmount = ForwarderWrapper.getPercentageOfValue(
+                ethValue,
+                MAX_WETH_FILL_PERCENTAGE,
+            );
+            const makerAssetFillAmount = primaryTakerAssetFillAmount
+                .times(orderWithoutFee.makerAssetAmount)
+                .dividedToIntegerBy(orderWithoutFee.takerAssetAmount);
+            const ethSpentOnFee = ForwarderWrapper.getPercentageOfValue(primaryTakerAssetFillAmount, baseFeePercentage);
+            const totalEthSpent = primaryTakerAssetFillAmount.plus(ethSpentOnFee).plus(gasPrice.times(tx.gasUsed));
+
+            expect(takerEthBalanceAfter).to.be.bignumber.equal(takerEthBalanceBefore.minus(totalEthSpent));
+            expect(newBalances[makerAddress][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[makerAddress][defaultMakerAssetAddress].minus(makerAssetFillAmount),
             );
-            expect(newBalances[forwarderContract.address][weth.address]).to.be.bignumber.equal(new BigNumber(0));
+            expect(newBalances[takerAddress][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[takerAddress][defaultMakerAssetAddress].plus(makerAssetFillAmount),
+            );
+            expect(newBalances[makerAddress][weth.address]).to.be.bignumber.equal(
+                erc20Balances[makerAddress][weth.address].plus(primaryTakerAssetFillAmount),
+            );
+            expect(newBalances[forwarderContract.address][weth.address]).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(newBalances[forwarderContract.address][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                constants.ZERO_AMOUNT,
+            );
+            expect(feeRecipientEthBalanceAfter).to.be.bignumber.equal(feeRecipientEthBalanceBefore.plus(ethSpentOnFee));
+            expect(forwarderEthBalance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
         });
         it('should fail if the fee is set too high', async () => {
-            const initEthBalance = await web3Wrapper.getBalanceInWeiAsync(feeRecipientAddress);
-            const fillAmount = signedOrder.takerAssetAmount.div(2);
-            feeProportion = 1500; // 15.0%
-            feeOrders = [];
+            const ethValue = orderWithoutFee.takerAssetAmount.div(2);
+            const baseFeePercentage = 6;
+            feePercentage = ForwarderWrapper.getPercentageOfValue(ethValue, baseFeePercentage);
+            const ordersWithoutFee = [orderWithoutFee];
+            const feeOrders: SignedOrder[] = [];
             await expectTransactionFailedAsync(
-                forwarderWrapper.marketSellEthForERC20Async(
-                    signedOrders,
+                forwarderWrapper.marketSellOrdersWithEthAsync(
+                    ordersWithoutFee,
                     feeOrders,
-                    { from: takerAddress, value: fillAmount, gasPrice: DEFAULT_GAS_PRICE },
-                    { feeProportion, feeRecipient: feeRecipientAddress },
+                    { from: takerAddress, value: ethValue, gasPrice },
+                    { feePercentage, feeRecipient: feeRecipientAddress },
                 ),
-                RevertReason.FeeProportionTooLarge,
+                RevertReason.FeePercentageTooLarge,
+            );
+        });
+        it('should fail if there is not enough ETH remaining to pay the fee', async () => {
+            const ethValue = orderWithoutFee.takerAssetAmount.div(2);
+            const baseFeePercentage = 5;
+            feePercentage = ForwarderWrapper.getPercentageOfValue(constants.PERCENTAGE_DENOMINATOR, baseFeePercentage);
+            const ordersWithFee = [orderWithFee];
+            const feeOrders = [feeOrder];
+            await expectTransactionFailedAsync(
+                forwarderWrapper.marketSellOrdersWithEthAsync(
+                    ordersWithFee,
+                    feeOrders,
+                    { from: takerAddress, value: ethValue, gasPrice },
+                    { feePercentage, feeRecipient: feeRecipientAddress },
+                ),
+                RevertReason.InsufficientEthRemaining,
             );
-            const afterEthBalance = await web3Wrapper.getBalanceInWeiAsync(feeRecipientAddress);
-            expect(afterEthBalance).to.be.bignumber.equal(initEthBalance);
         });
     });
-    describe('marketBuyTokensWithEth', () => {
-        it('should buy the exact amount of assets', async () => {
-            const makerAssetAmount = signedOrder.makerAssetAmount.div(2);
-            const initEthBalance = await web3Wrapper.getBalanceInWeiAsync(takerAddress);
-            const balancesBefore = await erc20Wrapper.getBalancesAsync();
-            const rate = signedOrder.makerAssetAmount.dividedBy(signedOrder.takerAssetAmount);
-            const fillAmountWei = makerAssetAmount.dividedToIntegerBy(rate);
-            feeOrders = [];
-            tx = await forwarderWrapper.marketBuyTokensWithEthAsync(signedOrders, feeOrders, makerAssetAmount, {
+    describe('marketBuyOrdersWithEth without extra fees', () => {
+        it('should buy the exact amount of makerAsset in a single order', async () => {
+            const ordersWithoutFee = [orderWithoutFee];
+            const feeOrders: SignedOrder[] = [];
+            const makerAssetFillAmount = orderWithoutFee.makerAssetAmount.dividedToIntegerBy(2);
+            const ethValue = orderWithoutFee.takerAssetAmount.dividedToIntegerBy(2);
+
+            tx = await forwarderWrapper.marketBuyOrdersWithEthAsync(ordersWithoutFee, feeOrders, makerAssetFillAmount, {
+                value: ethValue,
                 from: takerAddress,
-                value: fillAmountWei,
-                gasPrice: DEFAULT_GAS_PRICE,
             });
+            const takerEthBalanceAfter = await web3Wrapper.getBalanceInWeiAsync(takerAddress);
+            const forwarderEthBalance = await web3Wrapper.getBalanceInWeiAsync(forwarderContract.address);
             const newBalances = await erc20Wrapper.getBalancesAsync();
-            const takerBalanceBefore = balancesBefore[takerAddress][defaultMakerAssetAddress];
-            const takerBalanceAfter = newBalances[takerAddress][defaultMakerAssetAddress];
-            const afterEthBalance = await web3Wrapper.getBalanceInWeiAsync(takerAddress);
-            const expectedEthBalanceAfterGasCosts = initEthBalance.minus(fillAmountWei).minus(tx.gasUsed);
-            expect(takerBalanceAfter).to.be.bignumber.eq(takerBalanceBefore.plus(makerAssetAmount));
-            expect(afterEthBalance).to.be.bignumber.eq(expectedEthBalanceAfterGasCosts);
+
+            const primaryTakerAssetFillAmount = ethValue;
+            const totalEthSpent = primaryTakerAssetFillAmount.plus(gasPrice.times(tx.gasUsed));
+
+            expect(takerEthBalanceAfter).to.be.bignumber.equal(takerEthBalanceBefore.minus(totalEthSpent));
+            expect(newBalances[makerAddress][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[makerAddress][defaultMakerAssetAddress].minus(makerAssetFillAmount),
+            );
+            expect(newBalances[takerAddress][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[takerAddress][defaultMakerAssetAddress].plus(makerAssetFillAmount),
+            );
+            expect(newBalances[makerAddress][weth.address]).to.be.bignumber.equal(
+                erc20Balances[makerAddress][weth.address].plus(primaryTakerAssetFillAmount),
+            );
+            expect(newBalances[forwarderContract.address][weth.address]).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(newBalances[forwarderContract.address][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                constants.ZERO_AMOUNT,
+            );
+            expect(forwarderEthBalance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
         });
-        it('should buy the exact amount of assets and return excess ETH', async () => {
-            const makerAssetAmount = signedOrder.makerAssetAmount.div(2);
-            const initEthBalance = await web3Wrapper.getBalanceInWeiAsync(takerAddress);
-            const balancesBefore = await erc20Wrapper.getBalancesAsync();
-            const rate = signedOrder.makerAssetAmount.dividedBy(signedOrder.takerAssetAmount);
-            const fillAmount = makerAssetAmount.dividedToIntegerBy(rate);
-            const excessFillAmount = fillAmount.times(2);
-            feeOrders = [];
-            tx = await forwarderWrapper.marketBuyTokensWithEthAsync(signedOrders, feeOrders, makerAssetAmount, {
+        it('should buy the exact amount of makerAsset in multiple orders', async () => {
+            const secondOrderWithoutFee = await orderFactory.newSignedOrderAsync();
+            const ordersWithoutFee = [orderWithoutFee, secondOrderWithoutFee];
+            const feeOrders: SignedOrder[] = [];
+            const makerAssetFillAmount = ordersWithoutFee[0].makerAssetAmount.plus(
+                ordersWithoutFee[1].makerAssetAmount.dividedToIntegerBy(2),
+            );
+            const ethValue = ordersWithoutFee[0].takerAssetAmount.plus(
+                ordersWithoutFee[1].takerAssetAmount.dividedToIntegerBy(2),
+            );
+
+            tx = await forwarderWrapper.marketBuyOrdersWithEthAsync(ordersWithoutFee, feeOrders, makerAssetFillAmount, {
+                value: ethValue,
                 from: takerAddress,
-                value: excessFillAmount,
-                gasPrice: DEFAULT_GAS_PRICE,
             });
+            const takerEthBalanceAfter = await web3Wrapper.getBalanceInWeiAsync(takerAddress);
+            const forwarderEthBalance = await web3Wrapper.getBalanceInWeiAsync(forwarderContract.address);
             const newBalances = await erc20Wrapper.getBalancesAsync();
-            const takerBalanceBefore = balancesBefore[takerAddress][defaultMakerAssetAddress];
-            const takerBalanceAfter = newBalances[takerAddress][defaultMakerAssetAddress];
-            const afterEthBalance = await web3Wrapper.getBalanceInWeiAsync(takerAddress);
-            const expectedEthBalanceAfterGasCosts = initEthBalance.minus(fillAmount).minus(tx.gasUsed);
-            expect(takerBalanceAfter).to.be.bignumber.eq(takerBalanceBefore.plus(makerAssetAmount));
-            expect(afterEthBalance).to.be.bignumber.eq(expectedEthBalanceAfterGasCosts);
+
+            const primaryTakerAssetFillAmount = ethValue;
+            const totalEthSpent = primaryTakerAssetFillAmount.plus(gasPrice.times(tx.gasUsed));
+
+            expect(takerEthBalanceAfter).to.be.bignumber.equal(takerEthBalanceBefore.minus(totalEthSpent));
+            expect(newBalances[makerAddress][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[makerAddress][defaultMakerAssetAddress].minus(makerAssetFillAmount),
+            );
+            expect(newBalances[takerAddress][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[takerAddress][defaultMakerAssetAddress].plus(makerAssetFillAmount),
+            );
+            expect(newBalances[makerAddress][weth.address]).to.be.bignumber.equal(
+                erc20Balances[makerAddress][weth.address].plus(primaryTakerAssetFillAmount),
+            );
+            expect(newBalances[forwarderContract.address][weth.address]).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(newBalances[forwarderContract.address][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                constants.ZERO_AMOUNT,
+            );
+            expect(forwarderEthBalance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
         });
-        it('should buy the exact amount of assets with fee abstraction', async () => {
-            const makerAssetAmount = signedOrder.makerAssetAmount.div(2);
-            const balancesBefore = await erc20Wrapper.getBalancesAsync();
-            const rate = signedOrder.makerAssetAmount.dividedBy(signedOrder.takerAssetAmount);
-            const fillAmount = makerAssetAmount.dividedToIntegerBy(rate);
-            const excessFillAmount = fillAmount.times(2);
-            tx = await forwarderWrapper.marketBuyTokensWithEthAsync(signedOrdersWithFee, feeOrders, makerAssetAmount, {
+        it('should buy the exact amount of makerAsset and return excess ETH', async () => {
+            const ordersWithoutFee = [orderWithoutFee];
+            const feeOrders: SignedOrder[] = [];
+            const makerAssetFillAmount = orderWithoutFee.makerAssetAmount.dividedToIntegerBy(2);
+            const ethValue = orderWithoutFee.takerAssetAmount;
+
+            tx = await forwarderWrapper.marketBuyOrdersWithEthAsync(ordersWithoutFee, feeOrders, makerAssetFillAmount, {
+                value: ethValue,
                 from: takerAddress,
-                value: excessFillAmount,
             });
+            const takerEthBalanceAfter = await web3Wrapper.getBalanceInWeiAsync(takerAddress);
+            const forwarderEthBalance = await web3Wrapper.getBalanceInWeiAsync(forwarderContract.address);
             const newBalances = await erc20Wrapper.getBalancesAsync();
-            const takerBalanceBefore = balancesBefore[takerAddress][defaultMakerAssetAddress];
-            const takerBalanceAfter = newBalances[takerAddress][defaultMakerAssetAddress];
-            expect(takerBalanceAfter).to.be.bignumber.eq(takerBalanceBefore.plus(makerAssetAmount));
-        });
-        it('should buy the exact amount of assets when buying zrx with fee abstraction', async () => {
-            signedOrder = await orderFactory.newSignedOrderAsync({
-                makerAssetData: assetDataUtils.encodeERC20AssetData(zrxToken.address),
-                takerFee: Web3Wrapper.toBaseUnitAmount(new BigNumber(1), DECIMALS_DEFAULT),
-            });
-            signedOrdersWithFee = [signedOrder];
-            feeOrders = [];
-            const makerAssetAmount = signedOrder.makerAssetAmount.div(2);
-            const takerWeiBalanceBefore = await web3Wrapper.getBalanceInWeiAsync(takerAddress);
-            const balancesBefore = await erc20Wrapper.getBalancesAsync();
-            const fillAmountWei = await forwarderWrapper.calculateMarketBuyFillAmountWeiAsync(
-                signedOrdersWithFee,
-                feeOrders,
-                feeProportion,
-                makerAssetAmount,
+
+            const primaryTakerAssetFillAmount = ethValue.dividedToIntegerBy(2);
+            const totalEthSpent = primaryTakerAssetFillAmount.plus(gasPrice.times(tx.gasUsed));
+
+            expect(takerEthBalanceAfter).to.be.bignumber.equal(takerEthBalanceBefore.minus(totalEthSpent));
+            expect(newBalances[makerAddress][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[makerAddress][defaultMakerAssetAddress].minus(makerAssetFillAmount),
+            );
+            expect(newBalances[takerAddress][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[takerAddress][defaultMakerAssetAddress].plus(makerAssetFillAmount),
+            );
+            expect(newBalances[makerAddress][weth.address]).to.be.bignumber.equal(
+                erc20Balances[makerAddress][weth.address].plus(primaryTakerAssetFillAmount),
             );
-            tx = await forwarderWrapper.marketBuyTokensWithEthAsync(signedOrdersWithFee, feeOrders, makerAssetAmount, {
+            expect(newBalances[forwarderContract.address][weth.address]).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(newBalances[forwarderContract.address][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                constants.ZERO_AMOUNT,
+            );
+            expect(forwarderEthBalance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+        });
+        it('should buy the exact amount of makerAsset and pay ZRX from feeOrders', async () => {
+            const ordersWithFee = [orderWithFee];
+            const feeOrders = [feeOrder];
+            const makerAssetFillAmount = orderWithFee.makerAssetAmount.dividedToIntegerBy(2);
+            const ethValue = orderWithFee.takerAssetAmount;
+
+            tx = await forwarderWrapper.marketBuyOrdersWithEthAsync(ordersWithFee, feeOrders, makerAssetFillAmount, {
+                value: ethValue,
                 from: takerAddress,
-                value: fillAmountWei,
-                gasPrice: DEFAULT_GAS_PRICE,
             });
+            const takerEthBalanceAfter = await web3Wrapper.getBalanceInWeiAsync(takerAddress);
+            const forwarderEthBalance = await web3Wrapper.getBalanceInWeiAsync(forwarderContract.address);
             const newBalances = await erc20Wrapper.getBalancesAsync();
-            const takerTokenBalanceBefore = balancesBefore[takerAddress][zrxToken.address];
-            const takerTokenBalanceAfter = newBalances[takerAddress][zrxToken.address];
-            const takerWeiBalanceAfter = await web3Wrapper.getBalanceInWeiAsync(takerAddress);
-            const expectedCostAfterGas = fillAmountWei.plus(tx.gasUsed);
-            expect(takerTokenBalanceAfter).to.be.bignumber.greaterThan(takerTokenBalanceBefore.plus(makerAssetAmount));
-            expect(takerWeiBalanceAfter).to.be.bignumber.equal(takerWeiBalanceBefore.minus(expectedCostAfterGas));
-        });
-        it('throws if fees are higher than 5% when buying zrx', async () => {
-            const highFeeZRXOrder = await orderFactory.newSignedOrderAsync({
-                makerAssetData: assetDataUtils.encodeERC20AssetData(zrxToken.address),
-                makerAssetAmount: signedOrder.makerAssetAmount,
-                takerFee: signedOrder.makerAssetAmount.times(0.06),
-            });
-            signedOrdersWithFee = [highFeeZRXOrder];
-            feeOrders = [];
-            const makerAssetAmount = signedOrder.makerAssetAmount.div(2);
-            const fillAmountWei = await forwarderWrapper.calculateMarketBuyFillAmountWeiAsync(
-                signedOrdersWithFee,
-                feeOrders,
-                feeProportion,
-                makerAssetAmount,
+
+            const primaryTakerAssetFillAmount = orderWithFee.takerAssetAmount.dividedToIntegerBy(2);
+            const feeAmount = orderWithFee.takerFee.dividedToIntegerBy(2);
+            const wethSpentOnFeeOrders = ForwarderWrapper.getWethForFeeOrders(feeAmount, feeOrders);
+            const totalEthSpent = primaryTakerAssetFillAmount
+                .plus(wethSpentOnFeeOrders)
+                .plus(gasPrice.times(tx.gasUsed));
+
+            expect(takerEthBalanceAfter).to.be.bignumber.equal(takerEthBalanceBefore.minus(totalEthSpent));
+            expect(newBalances[makerAddress][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[makerAddress][defaultMakerAssetAddress].minus(makerAssetFillAmount),
             );
-            return expectTransactionFailedAsync(
-                forwarderWrapper.marketBuyTokensWithEthAsync(signedOrdersWithFee, feeOrders, makerAssetAmount, {
-                    from: takerAddress,
-                    value: fillAmountWei,
-                }),
-                RevertReason.UnacceptableThreshold,
+            expect(newBalances[takerAddress][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[takerAddress][defaultMakerAssetAddress].plus(makerAssetFillAmount),
             );
+            expect(newBalances[makerAddress][weth.address]).to.be.bignumber.equal(
+                erc20Balances[makerAddress][weth.address].plus(primaryTakerAssetFillAmount).plus(wethSpentOnFeeOrders),
+            );
+            expect(newBalances[forwarderContract.address][weth.address]).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(newBalances[forwarderContract.address][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                constants.ZERO_AMOUNT,
+            );
+            expect(forwarderEthBalance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
         });
-        it('throws if fees are higher than 5% when buying erc20', async () => {
-            const highFeeERC20Order = await orderFactory.newSignedOrderAsync({
-                takerFee: signedOrder.makerAssetAmount.times(0.06),
+        it('should buy slightly greater than makerAssetAmount when buying ZRX', async () => {
+            orderWithFee = await orderFactory.newSignedOrderAsync({
+                makerAssetData: assetDataUtils.encodeERC20AssetData(zrxToken.address),
+                takerFee: Web3Wrapper.toBaseUnitAmount(new BigNumber(1), DECIMALS_DEFAULT),
             });
-            signedOrdersWithFee = [highFeeERC20Order];
-            feeOrders = [feeOrder];
-            const makerAssetAmount = signedOrder.makerAssetAmount.div(2);
-            const fillAmountWei = await forwarderWrapper.calculateMarketBuyFillAmountWeiAsync(
-                signedOrdersWithFee,
-                feeOrders,
-                feeProportion,
-                makerAssetAmount,
+            const ordersWithFee = [orderWithFee];
+            const feeOrders: SignedOrder[] = [];
+            const makerAssetFillAmount = orderWithFee.makerAssetAmount.dividedToIntegerBy(2);
+            const ethValue = orderWithFee.takerAssetAmount;
+            tx = await forwarderWrapper.marketBuyOrdersWithEthAsync(ordersWithFee, feeOrders, makerAssetFillAmount, {
+                value: ethValue,
+                from: takerAddress,
+            });
+            const takerEthBalanceAfter = await web3Wrapper.getBalanceInWeiAsync(takerAddress);
+            const forwarderEthBalance = await web3Wrapper.getBalanceInWeiAsync(forwarderContract.address);
+            const newBalances = await erc20Wrapper.getBalancesAsync();
+
+            const primaryTakerAssetFillAmount = ForwarderWrapper.getWethForFeeOrders(
+                makerAssetFillAmount,
+                ordersWithFee,
             );
-            return expectTransactionFailedAsync(
-                forwarderWrapper.marketBuyTokensWithEthAsync(signedOrdersWithFee, feeOrders, makerAssetAmount, {
-                    from: takerAddress,
-                    value: fillAmountWei,
-                }),
-                RevertReason.UnacceptableThreshold as any,
+            const totalEthSpent = primaryTakerAssetFillAmount.plus(gasPrice.times(tx.gasUsed));
+            const makerAssetFilledAmount = orderWithFee.makerAssetAmount
+                .times(primaryTakerAssetFillAmount)
+                .dividedToIntegerBy(orderWithFee.takerAssetAmount);
+            const takerFeePaid = orderWithFee.takerFee
+                .times(primaryTakerAssetFillAmount)
+                .dividedToIntegerBy(orderWithFee.takerAssetAmount);
+            const makerFeePaid = orderWithFee.makerFee
+                .times(primaryTakerAssetFillAmount)
+                .dividedToIntegerBy(orderWithFee.takerAssetAmount);
+            const totalZrxPurchased = makerAssetFilledAmount.minus(takerFeePaid);
+            // Up to 1 wei worth of ZRX will be overbought per order
+            const maxOverboughtZrx = new BigNumber(1)
+                .times(orderWithFee.makerAssetAmount)
+                .dividedToIntegerBy(orderWithFee.takerAssetAmount);
+
+            expect(totalZrxPurchased).to.be.bignumber.gte(makerAssetFillAmount);
+            expect(totalZrxPurchased).to.be.bignumber.lte(makerAssetFillAmount.plus(maxOverboughtZrx));
+            expect(takerEthBalanceAfter).to.be.bignumber.equal(takerEthBalanceBefore.minus(totalEthSpent));
+            expect(newBalances[makerAddress][zrxToken.address]).to.be.bignumber.equal(
+                erc20Balances[makerAddress][zrxToken.address].minus(makerAssetFilledAmount).minus(makerFeePaid),
             );
-        });
-        it('throws if makerAssetAmount is 0', async () => {
-            const makerAssetAmount = new BigNumber(0);
-            const fillAmountWei = await forwarderWrapper.calculateMarketBuyFillAmountWeiAsync(
-                signedOrdersWithFee,
-                feeOrders,
-                feeProportion,
-                makerAssetAmount,
+            expect(newBalances[takerAddress][zrxToken.address]).to.be.bignumber.equal(
+                erc20Balances[takerAddress][zrxToken.address].plus(totalZrxPurchased),
             );
-            return expectTransactionFailedAsync(
-                forwarderWrapper.marketBuyTokensWithEthAsync(signedOrdersWithFee, feeOrders, makerAssetAmount, {
-                    from: takerAddress,
-                    value: fillAmountWei,
-                }),
-                RevertReason.ValueGreaterThanZero as any,
+            expect(newBalances[makerAddress][weth.address]).to.be.bignumber.equal(
+                erc20Balances[makerAddress][weth.address].plus(primaryTakerAssetFillAmount),
+            );
+            expect(newBalances[forwarderContract.address][weth.address]).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(newBalances[forwarderContract.address][zrxToken.address]).to.be.bignumber.equal(
+                erc20Balances[forwarderContract.address][zrxToken.address],
             );
+            expect(forwarderEthBalance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
         });
-        it('throws if the amount of ETH sent in is less than the takerAssetFilledAmount', async () => {
-            const makerAssetAmount = signedOrder.makerAssetAmount;
-            const fillAmount = signedOrder.takerAssetAmount.div(2);
-            const zero = new BigNumber(0);
-            // Deposit enough taker balance to fill the order
-            const wethDepositTxHash = await wethContract.deposit.sendTransactionAsync({
+        it('should not change balances if the amount of ETH sent is too low to fill the makerAssetAmount', async () => {
+            const ordersWithoutFee = [orderWithoutFee];
+            const feeOrders: SignedOrder[] = [];
+            const makerAssetFillAmount = orderWithoutFee.makerAssetAmount.dividedToIntegerBy(2);
+            const ethValue = orderWithoutFee.takerAssetAmount.dividedToIntegerBy(4);
+
+            tx = await forwarderWrapper.marketBuyOrdersWithEthAsync(ordersWithoutFee, feeOrders, makerAssetFillAmount, {
+                value: ethValue,
                 from: takerAddress,
-                value: signedOrder.takerAssetAmount,
             });
-            await web3Wrapper.awaitTransactionSuccessAsync(wethDepositTxHash);
-            // Transfer all of this WETH to the forwarding contract
-            const wethTransferTxHash = await wethContract.transfer.sendTransactionAsync(
-                forwarderContract.address,
-                signedOrder.takerAssetAmount,
-                { from: takerAddress },
-            );
-            await web3Wrapper.awaitTransactionSuccessAsync(wethTransferTxHash);
-            // We use the contract directly to get around wrapper validations and calculations
-            const formattedOrders = formatters.createMarketSellOrders(signedOrders, zero);
-            const formattedFeeOrders = formatters.createMarketSellOrders(feeOrders, zero);
-            return expectTransactionFailedAsync(
-                forwarderContract.marketBuyTokensWithEth.sendTransactionAsync(
-                    formattedOrders.orders,
-                    formattedOrders.signatures,
-                    formattedFeeOrders.orders,
-                    formattedFeeOrders.signatures,
-                    makerAssetAmount,
-                    zero,
-                    constants.NULL_ADDRESS,
-                    { value: fillAmount, from: takerAddress },
-                ),
-                RevertReason.InvalidMsgValue,
-            );
+            const takerEthBalanceAfter = await web3Wrapper.getBalanceInWeiAsync(takerAddress);
+            const forwarderEthBalance = await web3Wrapper.getBalanceInWeiAsync(forwarderContract.address);
+            const newBalances = await erc20Wrapper.getBalancesAsync();
+
+            const totalEthSpent = gasPrice.times(tx.gasUsed);
+
+            expect(takerEthBalanceAfter).to.be.bignumber.equal(takerEthBalanceBefore.minus(totalEthSpent));
+            expect(newBalances).to.deep.equal(erc20Balances);
+            expect(forwarderEthBalance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
         });
-    });
-    describe('marketBuyTokensWithEth - ERC721', async () => {
-        it('buys ERC721 assets', async () => {
+        it('should buy an ERC721 asset from a single order', async () => {
             const makerAssetId = erc721MakerAssetIds[0];
-            signedOrder = await orderFactory.newSignedOrderAsync({
+            orderWithoutFee = await orderFactory.newSignedOrderAsync({
                 makerAssetAmount: new BigNumber(1),
                 makerAssetData: assetDataUtils.encodeERC721AssetData(erc721Token.address, makerAssetId),
             });
-            feeOrders = [];
-            signedOrders = [signedOrder];
-            const makerAssetAmount = new BigNumber(signedOrders.length);
-            const fillAmountWei = await forwarderWrapper.calculateMarketBuyFillAmountWeiAsync(
-                signedOrders,
-                feeOrders,
-                feeProportion,
-                makerAssetAmount,
-            );
-            tx = await forwarderWrapper.marketBuyTokensWithEthAsync(signedOrders, feeOrders, makerAssetAmount, {
+            const ordersWithoutFee = [orderWithoutFee];
+            const feeOrders: SignedOrder[] = [];
+            const makerAssetFillAmount = new BigNumber(1);
+            const ethValue = orderWithFee.takerAssetAmount;
+
+            tx = await forwarderWrapper.marketBuyOrdersWithEthAsync(ordersWithoutFee, feeOrders, makerAssetFillAmount, {
                 from: takerAddress,
-                value: fillAmountWei,
+                value: ethValue,
             });
-            const newOwnerTakerAsset = await erc721Token.ownerOf.callAsync(makerAssetId);
-            expect(newOwnerTakerAsset).to.be.bignumber.equal(takerAddress);
+            const takerEthBalanceAfter = await web3Wrapper.getBalanceInWeiAsync(takerAddress);
+            const forwarderEthBalance = await web3Wrapper.getBalanceInWeiAsync(forwarderContract.address);
+            const newOwner = await erc721Token.ownerOf.callAsync(makerAssetId);
+            const newBalances = await erc20Wrapper.getBalancesAsync();
+
+            const primaryTakerAssetFillAmount = ethValue;
+            const totalEthSpent = primaryTakerAssetFillAmount.plus(gasPrice.times(tx.gasUsed));
+            expect(newOwner).to.be.bignumber.equal(takerAddress);
+            expect(takerEthBalanceAfter).to.be.bignumber.equal(takerEthBalanceBefore.minus(totalEthSpent));
+            expect(newBalances[makerAddress][weth.address]).to.be.bignumber.equal(
+                erc20Balances[makerAddress][weth.address].plus(primaryTakerAssetFillAmount),
+            );
+            expect(newBalances[forwarderContract.address][weth.address]).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(newBalances[forwarderContract.address][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                constants.ZERO_AMOUNT,
+            );
+            expect(forwarderEthBalance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
         });
-        it('buys ERC721 assets with fee abstraction', async () => {
+        it('should buy an ERC721 asset and ignore later orders with different makerAssetData', async () => {
             const makerAssetId = erc721MakerAssetIds[0];
-            signedOrder = await orderFactory.newSignedOrderAsync({
+            orderWithoutFee = await orderFactory.newSignedOrderAsync({
                 makerAssetAmount: new BigNumber(1),
-                takerFee: Web3Wrapper.toBaseUnitAmount(new BigNumber(1), DECIMALS_DEFAULT),
                 makerAssetData: assetDataUtils.encodeERC721AssetData(erc721Token.address, makerAssetId),
             });
-            signedOrders = [signedOrder];
-            const makerAssetAmount = new BigNumber(signedOrders.length);
-            const fillAmountWei = await forwarderWrapper.calculateMarketBuyFillAmountWeiAsync(
-                signedOrders,
-                feeOrders,
-                feeProportion,
-                makerAssetAmount,
-            );
-            tx = await forwarderWrapper.marketBuyTokensWithEthAsync(signedOrders, feeOrders, makerAssetAmount, {
+            const differentMakerAssetDataOrder = await orderFactory.newSignedOrderAsync();
+            const ordersWithoutFee = [orderWithoutFee, differentMakerAssetDataOrder];
+            const feeOrders: SignedOrder[] = [];
+            const makerAssetFillAmount = new BigNumber(1).plus(differentMakerAssetDataOrder.makerAssetAmount);
+            const ethValue = orderWithFee.takerAssetAmount;
+
+            tx = await forwarderWrapper.marketBuyOrdersWithEthAsync(ordersWithoutFee, feeOrders, makerAssetFillAmount, {
                 from: takerAddress,
-                value: fillAmountWei,
+                value: ethValue,
             });
-            const newOwnerTakerAsset = await erc721Token.ownerOf.callAsync(makerAssetId);
-            expect(newOwnerTakerAsset).to.be.bignumber.equal(takerAddress);
-        });
-        it('buys ERC721 assets with fee abstraction and pays fee to fee recipient', async () => {
-            const makerAssetId = erc721MakerAssetIds[0];
-            signedOrder = await orderFactory.newSignedOrderAsync({
-                makerAssetAmount: new BigNumber(1),
-                takerFee: Web3Wrapper.toBaseUnitAmount(new BigNumber(1), DECIMALS_DEFAULT),
-                makerAssetData: assetDataUtils.encodeERC721AssetData(erc721Token.address, makerAssetId),
-            });
-            signedOrders = [signedOrder];
-            feeProportion = 100;
-            const initTakerBalanceWei = await web3Wrapper.getBalanceInWeiAsync(takerAddress);
-            const initFeeRecipientBalanceWei = await web3Wrapper.getBalanceInWeiAsync(feeRecipientAddress);
-            const makerAssetAmount = new BigNumber(signedOrders.length);
-            const fillAmountWei = await forwarderWrapper.calculateMarketBuyFillAmountWeiAsync(
-                signedOrders,
-                feeOrders,
-                feeProportion,
-                makerAssetAmount,
+            const takerEthBalanceAfter = await web3Wrapper.getBalanceInWeiAsync(takerAddress);
+            const forwarderEthBalance = await web3Wrapper.getBalanceInWeiAsync(forwarderContract.address);
+            const newOwner = await erc721Token.ownerOf.callAsync(makerAssetId);
+            const newBalances = await erc20Wrapper.getBalancesAsync();
+
+            const primaryTakerAssetFillAmount = ethValue;
+            const totalEthSpent = primaryTakerAssetFillAmount.plus(gasPrice.times(tx.gasUsed));
+            expect(newOwner).to.be.bignumber.equal(takerAddress);
+            expect(takerEthBalanceAfter).to.be.bignumber.equal(takerEthBalanceBefore.minus(totalEthSpent));
+            expect(newBalances[makerAddress][weth.address]).to.be.bignumber.equal(
+                erc20Balances[makerAddress][weth.address].plus(primaryTakerAssetFillAmount),
             );
-            tx = await forwarderWrapper.marketBuyTokensWithEthAsync(
-                signedOrders,
-                feeOrders,
-                makerAssetAmount,
-                {
-                    from: takerAddress,
-                    value: fillAmountWei,
-                    gasPrice: DEFAULT_GAS_PRICE,
-                },
-                {
-                    feeProportion,
-                    feeRecipient: feeRecipientAddress,
-                },
+            expect(newBalances[forwarderContract.address][weth.address]).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(newBalances[forwarderContract.address][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                constants.ZERO_AMOUNT,
             );
-            const afterFeeRecipientEthBalance = await web3Wrapper.getBalanceInWeiAsync(feeRecipientAddress);
-            const afterTakerBalanceWei = await web3Wrapper.getBalanceInWeiAsync(takerAddress);
-            const takerFilledAmount = initTakerBalanceWei.minus(afterTakerBalanceWei).plus(tx.gasUsed);
-            const newOwnerTakerAsset = await erc721Token.ownerOf.callAsync(makerAssetId);
-            expect(newOwnerTakerAsset).to.be.bignumber.equal(takerAddress);
-            const balanceDiff = afterFeeRecipientEthBalance.minus(initFeeRecipientBalanceWei);
-            expect(takerFilledAmount.dividedToIntegerBy(balanceDiff)).to.be.bignumber.equal(101);
-            expect(takerFilledAmount.minus(balanceDiff).dividedToIntegerBy(balanceDiff)).to.be.bignumber.equal(100);
-        });
-        it('buys multiple ERC721 assets with fee abstraction and pays fee to fee recipient', async () => {
-            const makerAssetId1 = erc721MakerAssetIds[0];
-            const makerAssetId2 = erc721MakerAssetIds[1];
-            const signedOrder1 = await orderFactory.newSignedOrderAsync({
-                makerAssetAmount: new BigNumber(1),
-                takerFee: Web3Wrapper.toBaseUnitAmount(new BigNumber(3), DECIMALS_DEFAULT),
-                makerAssetData: assetDataUtils.encodeERC721AssetData(erc721Token.address, makerAssetId1),
-            });
-            const signedOrder2 = await orderFactory.newSignedOrderAsync({
-                makerAssetAmount: new BigNumber(1),
-                takerFee: Web3Wrapper.toBaseUnitAmount(new BigNumber(4), DECIMALS_DEFAULT),
-                makerAssetData: assetDataUtils.encodeERC721AssetData(erc721Token.address, makerAssetId2),
-            });
-            signedOrders = [signedOrder1, signedOrder2];
-            feeProportion = 10;
-            const makerAssetAmount = new BigNumber(signedOrders.length);
-            const fillAmountWei = await forwarderWrapper.calculateMarketBuyFillAmountWeiAsync(
-                signedOrders,
-                feeOrders,
-                feeProportion,
-                makerAssetAmount,
+            expect(forwarderEthBalance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(newBalances[makerAddress][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[makerAddress][defaultMakerAssetAddress],
+            );
+            expect(newBalances[takerAddress][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[takerAddress][defaultMakerAssetAddress],
             );
-            tx = await forwarderWrapper.marketBuyTokensWithEthAsync(signedOrders, feeOrders, makerAssetAmount, {
-                from: takerAddress,
-                value: fillAmountWei,
-            });
-            const newOwnerTakerAsset1 = await erc721Token.ownerOf.callAsync(makerAssetId1);
-            expect(newOwnerTakerAsset1).to.be.bignumber.equal(takerAddress);
-            const newOwnerTakerAsset2 = await erc721Token.ownerOf.callAsync(makerAssetId2);
-            expect(newOwnerTakerAsset2).to.be.bignumber.equal(takerAddress);
         });
-        it('buys ERC721 assets with fee abstraction and handles fee orders filled and excess eth', async () => {
+        it('should buy an ERC721 asset and pay ZRX fees from a single fee order', async () => {
             const makerAssetId = erc721MakerAssetIds[0];
-            feeProportion = 0;
-            // In this scenario a total of 6 ZRX fees need to be paid.
-            // There are two fee orders, but the first fee order is partially filled while
-            // the Forwarding contract tx is in the mempool.
-            const erc721MakerAssetAmount = new BigNumber(1);
-            signedOrder = await orderFactory.newSignedOrderAsync({
-                makerAssetAmount: erc721MakerAssetAmount,
-                takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(10), DECIMALS_DEFAULT),
-                takerFee: Web3Wrapper.toBaseUnitAmount(new BigNumber(6), DECIMALS_DEFAULT),
+            orderWithFee = await orderFactory.newSignedOrderAsync({
+                makerAssetAmount: new BigNumber(1),
                 makerAssetData: assetDataUtils.encodeERC721AssetData(erc721Token.address, makerAssetId),
+                takerFee: Web3Wrapper.toBaseUnitAmount(new BigNumber(1), DECIMALS_DEFAULT),
             });
-            signedOrders = [signedOrder];
-            const firstFeeOrder = await orderFactory.newSignedOrderAsync({
-                makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(8), DECIMALS_DEFAULT),
-                takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(0.1), DECIMALS_DEFAULT),
-                makerAssetData: assetDataUtils.encodeERC20AssetData(zrxToken.address),
-                takerFee: Web3Wrapper.toBaseUnitAmount(new BigNumber(0), DECIMALS_DEFAULT),
-            });
-            const secondFeeOrder = await orderFactory.newSignedOrderAsync({
-                makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(8), DECIMALS_DEFAULT),
-                takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(0.12), DECIMALS_DEFAULT),
-                makerAssetData: assetDataUtils.encodeERC20AssetData(zrxToken.address),
-                takerFee: Web3Wrapper.toBaseUnitAmount(new BigNumber(0), DECIMALS_DEFAULT),
-            });
-            feeOrders = [firstFeeOrder, secondFeeOrder];
-            const makerAssetAmount = new BigNumber(signedOrders.length);
-            const fillAmountWei = await forwarderWrapper.calculateMarketBuyFillAmountWeiAsync(
-                signedOrders,
-                feeOrders,
-                feeProportion,
-                erc721MakerAssetAmount,
-            );
-            // Simulate another otherAddress user partially filling firstFeeOrder
-            const firstFeeOrderFillAmount = firstFeeOrder.makerAssetAmount.div(2);
-            tx = await forwarderWrapper.marketBuyTokensWithEthAsync([firstFeeOrder], [], firstFeeOrderFillAmount, {
-                from: otherAddress,
-                value: fillAmountWei,
-            });
-            // For tests we calculate how much this should've cost given that firstFeeOrder was filled
-            const expectedFillAmountWei = await forwarderWrapper.calculateMarketBuyFillAmountWeiAsync(
-                signedOrders,
-                feeOrders,
-                feeProportion,
-                erc721MakerAssetAmount,
-            );
-            // With 4 ZRX remaining in firstFeeOrder, the secondFeeOrder will need to be filled to make up
-            // the total amount of fees required (6)
-            // Since the fee orders can be filled while the transaction is pending the user safely sends in
-            // extra ether to cover any slippage
-            const initEthBalance = await web3Wrapper.getBalanceInWeiAsync(takerAddress);
-            const slippageFillAmountWei = fillAmountWei.times(2);
-            tx = await forwarderWrapper.marketBuyTokensWithEthAsync(signedOrders, feeOrders, makerAssetAmount, {
+            const ordersWithFee = [orderWithFee];
+            const feeOrders = [feeOrder];
+            const makerAssetFillAmount = orderWithFee.makerAssetAmount;
+            const primaryTakerAssetFillAmount = orderWithFee.takerAssetAmount;
+            const feeAmount = orderWithFee.takerFee;
+            const wethSpentOnFeeOrders = ForwarderWrapper.getWethForFeeOrders(feeAmount, feeOrders);
+            const ethValue = primaryTakerAssetFillAmount.plus(wethSpentOnFeeOrders);
+
+            tx = await forwarderWrapper.marketBuyOrdersWithEthAsync(ordersWithFee, feeOrders, makerAssetFillAmount, {
+                value: ethValue,
                 from: takerAddress,
-                value: slippageFillAmountWei,
-                gasPrice: DEFAULT_GAS_PRICE,
             });
-            const afterEthBalance = await web3Wrapper.getBalanceInWeiAsync(takerAddress);
-            const expectedEthBalanceAfterGasCosts = initEthBalance.minus(expectedFillAmountWei).minus(tx.gasUsed);
-            const newOwnerTakerAsset = await erc721Token.ownerOf.callAsync(makerAssetId);
-            expect(newOwnerTakerAsset).to.be.bignumber.equal(takerAddress);
-            expect(afterEthBalance).to.be.bignumber.equal(expectedEthBalanceAfterGasCosts);
+            const takerEthBalanceAfter = await web3Wrapper.getBalanceInWeiAsync(takerAddress);
+            const forwarderEthBalance = await web3Wrapper.getBalanceInWeiAsync(forwarderContract.address);
+            const newOwner = await erc721Token.ownerOf.callAsync(makerAssetId);
+            const newBalances = await erc20Wrapper.getBalancesAsync();
+
+            const totalEthSpent = ethValue.plus(gasPrice.times(tx.gasUsed));
+
+            expect(newOwner).to.be.bignumber.equal(takerAddress);
+            expect(takerEthBalanceAfter).to.be.bignumber.equal(takerEthBalanceBefore.minus(totalEthSpent));
+            expect(newBalances[makerAddress][weth.address]).to.be.bignumber.equal(
+                erc20Balances[makerAddress][weth.address].plus(primaryTakerAssetFillAmount).plus(wethSpentOnFeeOrders),
+            );
+            expect(newBalances[forwarderContract.address][weth.address]).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(newBalances[forwarderContract.address][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                constants.ZERO_AMOUNT,
+            );
+            expect(forwarderEthBalance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
         });
-        it('buys ERC721 assets with fee abstraction and handles fee orders filled', async () => {
+        it('should buy an ERC721 asset and pay ZRX fees from multiple fee orders', async () => {
             const makerAssetId = erc721MakerAssetIds[0];
-            feeProportion = 0;
-            // In this scenario a total of 6 ZRX fees need to be paid.
-            // There are two fee orders, but the first fee order is partially filled while
-            // the Forwarding contract tx is in the mempool.
-            const erc721MakerAssetAmount = new BigNumber(1);
-            signedOrder = await orderFactory.newSignedOrderAsync({
-                makerAssetAmount: erc721MakerAssetAmount,
-                takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(10), DECIMALS_DEFAULT),
-                takerFee: Web3Wrapper.toBaseUnitAmount(new BigNumber(6), DECIMALS_DEFAULT),
+            orderWithFee = await orderFactory.newSignedOrderAsync({
+                makerAssetAmount: new BigNumber(1),
                 makerAssetData: assetDataUtils.encodeERC721AssetData(erc721Token.address, makerAssetId),
+                takerFee: Web3Wrapper.toBaseUnitAmount(new BigNumber(1), DECIMALS_DEFAULT),
             });
-            const zrxMakerAssetAmount = Web3Wrapper.toBaseUnitAmount(new BigNumber(8), DECIMALS_DEFAULT);
-            signedOrders = [signedOrder];
+            const ordersWithFee = [orderWithFee];
+            const makerAssetData = assetDataUtils.encodeERC20AssetData(zrxToken.address);
+            const makerAssetAmount = orderWithFee.takerFee.dividedToIntegerBy(2);
+            const takerAssetAmount = feeOrder.takerAssetAmount
+                .times(makerAssetAmount)
+                .dividedToIntegerBy(feeOrder.makerAssetAmount);
+
             const firstFeeOrder = await orderFactory.newSignedOrderAsync({
-                makerAssetAmount: zrxMakerAssetAmount,
-                takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(0.1), DECIMALS_DEFAULT),
-                makerAssetData: assetDataUtils.encodeERC20AssetData(zrxToken.address),
-                takerFee: Web3Wrapper.toBaseUnitAmount(new BigNumber(0), DECIMALS_DEFAULT),
+                makerAssetData,
+                makerAssetAmount,
+                takerAssetAmount,
             });
             const secondFeeOrder = await orderFactory.newSignedOrderAsync({
-                makerAssetAmount: zrxMakerAssetAmount,
-                takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(0.12), DECIMALS_DEFAULT),
-                makerAssetData: assetDataUtils.encodeERC20AssetData(zrxToken.address),
-                takerFee: Web3Wrapper.toBaseUnitAmount(new BigNumber(0), DECIMALS_DEFAULT),
-            });
-            feeOrders = [firstFeeOrder, secondFeeOrder];
-            const makerAssetAmount = new BigNumber(signedOrders.length);
-            const fillAmountWei = await forwarderWrapper.calculateMarketBuyFillAmountWeiAsync(
-                signedOrders,
-                feeOrders,
-                feeProportion,
-                erc721MakerAssetAmount,
-            );
-            // Simulate another otherAddress user partially filling firstFeeOrder
-            const firstFeeOrderFillAmount = firstFeeOrder.makerAssetAmount.div(2);
-            tx = await forwarderWrapper.marketBuyTokensWithEthAsync([firstFeeOrder], [], firstFeeOrderFillAmount, {
-                from: otherAddress,
-                value: fillAmountWei,
+                makerAssetData,
+                makerAssetAmount,
+                takerAssetAmount,
             });
-            const expectedFillAmountWei = await forwarderWrapper.calculateMarketBuyFillAmountWeiAsync(
-                signedOrders,
-                feeOrders,
-                feeProportion,
-                erc721MakerAssetAmount,
-            );
-            tx = await forwarderWrapper.marketBuyTokensWithEthAsync(signedOrders, feeOrders, makerAssetAmount, {
+            const feeOrders = [firstFeeOrder, secondFeeOrder];
+
+            const makerAssetFillAmount = orderWithFee.makerAssetAmount;
+            const primaryTakerAssetFillAmount = orderWithFee.takerAssetAmount;
+            const feeAmount = orderWithFee.takerFee;
+            const wethSpentOnFeeOrders = ForwarderWrapper.getWethForFeeOrders(feeAmount, feeOrders);
+            const ethValue = primaryTakerAssetFillAmount.plus(wethSpentOnFeeOrders);
+
+            tx = await forwarderWrapper.marketBuyOrdersWithEthAsync(ordersWithFee, feeOrders, makerAssetFillAmount, {
+                value: ethValue,
                 from: takerAddress,
-                value: expectedFillAmountWei,
             });
-            const newOwnerTakerAsset = await erc721Token.ownerOf.callAsync(makerAssetId);
-            expect(newOwnerTakerAsset).to.be.bignumber.equal(takerAddress);
+            const takerEthBalanceAfter = await web3Wrapper.getBalanceInWeiAsync(takerAddress);
+            const forwarderEthBalance = await web3Wrapper.getBalanceInWeiAsync(forwarderContract.address);
+            const newOwner = await erc721Token.ownerOf.callAsync(makerAssetId);
+            const newBalances = await erc20Wrapper.getBalancesAsync();
+
+            const totalEthSpent = ethValue.plus(gasPrice.times(tx.gasUsed));
+
+            expect(newOwner).to.be.bignumber.equal(takerAddress);
+            expect(takerEthBalanceAfter).to.be.bignumber.equal(takerEthBalanceBefore.minus(totalEthSpent));
+            expect(newBalances[makerAddress][weth.address]).to.be.bignumber.equal(
+                erc20Balances[makerAddress][weth.address].plus(primaryTakerAssetFillAmount).plus(wethSpentOnFeeOrders),
+            );
+            expect(newBalances[forwarderContract.address][weth.address]).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(newBalances[forwarderContract.address][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                constants.ZERO_AMOUNT,
+            );
+            expect(forwarderEthBalance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
         });
-        it('throws when mixed ERC721 and ERC20 assets', async () => {
-            const makerAssetId = erc721MakerAssetIds[0];
-            const erc721SignedOrder = await orderFactory.newSignedOrderAsync({
-                makerAssetAmount: new BigNumber(1),
-                makerAssetData: assetDataUtils.encodeERC721AssetData(erc721Token.address, makerAssetId),
-            });
-            const erc20SignedOrder = await orderFactory.newSignedOrderAsync();
-            signedOrders = [erc721SignedOrder, erc20SignedOrder];
-            const makerAssetAmount = new BigNumber(signedOrders.length);
-            const fillAmountWei = erc20SignedOrder.takerAssetAmount.plus(erc721SignedOrder.takerAssetAmount);
-            return expectTransactionFailedAsync(
-                forwarderWrapper.marketBuyTokensWithEthAsync(signedOrders, feeOrders, makerAssetAmount, {
+    });
+    describe('marketBuyOrdersWithEth with extra fees', () => {
+        it('should buy an asset and send fee to feeRecipient', async () => {
+            const ordersWithoutFee = [orderWithoutFee];
+            const feeOrders: SignedOrder[] = [];
+            const makerAssetFillAmount = orderWithoutFee.makerAssetAmount.dividedToIntegerBy(2);
+            const ethValue = orderWithoutFee.takerAssetAmount;
+
+            const baseFeePercentage = 2;
+            feePercentage = ForwarderWrapper.getPercentageOfValue(constants.PERCENTAGE_DENOMINATOR, baseFeePercentage);
+            const feeRecipientEthBalanceBefore = await web3Wrapper.getBalanceInWeiAsync(feeRecipientAddress);
+            tx = await forwarderWrapper.marketBuyOrdersWithEthAsync(
+                ordersWithoutFee,
+                feeOrders,
+                makerAssetFillAmount,
+                {
+                    value: ethValue,
                     from: takerAddress,
-                    value: fillAmountWei,
-                }),
-                RevertReason.LibBytesGreaterOrEqualTo32LengthRequired,
+                },
+                { feePercentage, feeRecipient: feeRecipientAddress },
             );
+            const takerEthBalanceAfter = await web3Wrapper.getBalanceInWeiAsync(takerAddress);
+            const forwarderEthBalance = await web3Wrapper.getBalanceInWeiAsync(forwarderContract.address);
+            const feeRecipientEthBalanceAfter = await web3Wrapper.getBalanceInWeiAsync(feeRecipientAddress);
+            const newBalances = await erc20Wrapper.getBalancesAsync();
+
+            const primaryTakerAssetFillAmount = orderWithoutFee.takerAssetAmount.dividedToIntegerBy(2);
+            const ethSpentOnFee = ForwarderWrapper.getPercentageOfValue(primaryTakerAssetFillAmount, baseFeePercentage);
+            const totalEthSpent = primaryTakerAssetFillAmount.plus(ethSpentOnFee).plus(gasPrice.times(tx.gasUsed));
+
+            expect(feeRecipientEthBalanceAfter).to.be.bignumber.equal(feeRecipientEthBalanceBefore.plus(ethSpentOnFee));
+            expect(takerEthBalanceAfter).to.be.bignumber.equal(takerEthBalanceBefore.minus(totalEthSpent));
+            expect(newBalances[makerAddress][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[makerAddress][defaultMakerAssetAddress].minus(makerAssetFillAmount),
+            );
+            expect(newBalances[takerAddress][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                erc20Balances[takerAddress][defaultMakerAssetAddress].plus(makerAssetFillAmount),
+            );
+            expect(newBalances[makerAddress][weth.address]).to.be.bignumber.equal(
+                erc20Balances[makerAddress][weth.address].plus(primaryTakerAssetFillAmount),
+            );
+            expect(newBalances[forwarderContract.address][weth.address]).to.be.bignumber.equal(constants.ZERO_AMOUNT);
+            expect(newBalances[forwarderContract.address][defaultMakerAssetAddress]).to.be.bignumber.equal(
+                constants.ZERO_AMOUNT,
+            );
+            expect(forwarderEthBalance).to.be.bignumber.equal(constants.ZERO_AMOUNT);
         });
-        it('throws when mixed ERC721 and ERC20 assets with ERC20 first', async () => {
-            const makerAssetId = erc721MakerAssetIds[0];
-            const erc721SignedOrder = await orderFactory.newSignedOrderAsync({
-                makerAssetAmount: new BigNumber(1),
-                makerAssetData: assetDataUtils.encodeERC721AssetData(erc721Token.address, makerAssetId),
-            });
-            const erc20SignedOrder = await orderFactory.newSignedOrderAsync();
-            signedOrders = [erc20SignedOrder, erc721SignedOrder];
-            const makerAssetAmount = new BigNumber(signedOrders.length);
-            const fillAmountWei = erc20SignedOrder.takerAssetAmount.plus(erc721SignedOrder.takerAssetAmount);
-            return expectTransactionFailedAsync(
-                forwarderWrapper.marketBuyTokensWithEthAsync(signedOrders, feeOrders, makerAssetAmount, {
-                    from: takerAddress,
-                    value: fillAmountWei,
-                }),
-                RevertReason.InvalidTakerAmount,
+        it('should fail if the fee is set too high', async () => {
+            const ordersWithoutFee = [orderWithoutFee];
+            const feeOrders: SignedOrder[] = [];
+            const makerAssetFillAmount = orderWithoutFee.makerAssetAmount.dividedToIntegerBy(2);
+            const ethValue = orderWithoutFee.takerAssetAmount;
+
+            const baseFeePercentage = 6;
+            feePercentage = ForwarderWrapper.getPercentageOfValue(constants.PERCENTAGE_DENOMINATOR, baseFeePercentage);
+            await expectTransactionFailedAsync(
+                forwarderWrapper.marketBuyOrdersWithEthAsync(
+                    ordersWithoutFee,
+                    feeOrders,
+                    makerAssetFillAmount,
+                    {
+                        value: ethValue,
+                        from: takerAddress,
+                    },
+                    { feePercentage, feeRecipient: feeRecipientAddress },
+                ),
+                RevertReason.FeePercentageTooLarge,
+            );
+        });
+        it('should fail if there is not enough ETH remaining to pay the fee', async () => {
+            const ordersWithoutFee = [orderWithoutFee];
+            const feeOrders: SignedOrder[] = [];
+            const makerAssetFillAmount = orderWithoutFee.makerAssetAmount.dividedToIntegerBy(2);
+            const ethValue = orderWithoutFee.takerAssetAmount.dividedToIntegerBy(2);
+
+            const baseFeePercentage = 2;
+            feePercentage = ForwarderWrapper.getPercentageOfValue(constants.PERCENTAGE_DENOMINATOR, baseFeePercentage);
+            await expectTransactionFailedAsync(
+                forwarderWrapper.marketBuyOrdersWithEthAsync(
+                    ordersWithoutFee,
+                    feeOrders,
+                    makerAssetFillAmount,
+                    {
+                        value: ethValue,
+                        from: takerAddress,
+                    },
+                    { feePercentage, feeRecipient: feeRecipientAddress },
+                ),
+                RevertReason.InsufficientEthRemaining,
             );
         });
     });
diff --git a/packages/contracts/test/utils/artifacts.ts b/packages/contracts/test/utils/artifacts.ts
index d3f808218..63bd555a4 100644
--- a/packages/contracts/test/utils/artifacts.ts
+++ b/packages/contracts/test/utils/artifacts.ts
@@ -15,12 +15,13 @@ import * as MultiSigWallet from '../../artifacts/MultiSigWallet.json';
 import * as MultiSigWalletWithTimeLock from '../../artifacts/MultiSigWalletWithTimeLock.json';
 import * as TestAssetProxyDispatcher from '../../artifacts/TestAssetProxyDispatcher.json';
 import * as TestAssetProxyOwner from '../../artifacts/TestAssetProxyOwner.json';
+import * as TestConstants from '../../artifacts/TestConstants.json';
 import * as TestLibBytes from '../../artifacts/TestLibBytes.json';
 import * as TestLibs from '../../artifacts/TestLibs.json';
 import * as TestSignatureValidator from '../../artifacts/TestSignatureValidator.json';
-import * as TestValidator from '../../artifacts/TestValidator.json';
-import * as TestWallet from '../../artifacts/TestWallet.json';
 import * as TokenRegistry from '../../artifacts/TokenRegistry.json';
+import * as Validator from '../../artifacts/Validator.json';
+import * as Wallet from '../../artifacts/Wallet.json';
 import * as EtherToken from '../../artifacts/WETH9.json';
 import * as Whitelist from '../../artifacts/Whitelist.json';
 import * as ZRX from '../../artifacts/ZRXToken.json';
@@ -42,11 +43,12 @@ export const artifacts = {
     MultiSigWalletWithTimeLock: (MultiSigWalletWithTimeLock as any) as ContractArtifact,
     TestAssetProxyOwner: (TestAssetProxyOwner as any) as ContractArtifact,
     TestAssetProxyDispatcher: (TestAssetProxyDispatcher as any) as ContractArtifact,
+    TestConstants: (TestConstants as any) as ContractArtifact,
     TestLibBytes: (TestLibBytes as any) as ContractArtifact,
     TestLibs: (TestLibs as any) as ContractArtifact,
     TestSignatureValidator: (TestSignatureValidator as any) as ContractArtifact,
-    TestValidator: (TestValidator as any) as ContractArtifact,
-    TestWallet: (TestWallet as any) as ContractArtifact,
+    Validator: (Validator as any) as ContractArtifact,
+    Wallet: (Wallet as any) as ContractArtifact,
     TokenRegistry: (TokenRegistry as any) as ContractArtifact,
     Whitelist: (Whitelist as any) as ContractArtifact,
     ZRX: (ZRX as any) as ContractArtifact,
diff --git a/packages/contracts/test/utils/constants.ts b/packages/contracts/test/utils/constants.ts
index 7dac38f56..65eaee398 100644
--- a/packages/contracts/test/utils/constants.ts
+++ b/packages/contracts/test/utils/constants.ts
@@ -49,4 +49,6 @@ export const constants = {
         takerFee: Web3Wrapper.toBaseUnitAmount(new BigNumber(1), 18),
     },
     WORD_LENGTH: 32,
+    ZERO_AMOUNT: new BigNumber(0),
+    PERCENTAGE_DENOMINATOR: new BigNumber(10).pow(18),
 };
diff --git a/packages/contracts/test/utils/forwarder_wrapper.ts b/packages/contracts/test/utils/forwarder_wrapper.ts
index e39df14b1..ef7476e36 100644
--- a/packages/contracts/test/utils/forwarder_wrapper.ts
+++ b/packages/contracts/test/utils/forwarder_wrapper.ts
@@ -1,5 +1,4 @@
-import { assetDataUtils } from '@0xproject/order-utils';
-import { AssetProxyId, SignedOrder } from '@0xproject/types';
+import { SignedOrder } from '@0xproject/types';
 import { BigNumber } from '@0xproject/utils';
 import { Web3Wrapper } from '@0xproject/web3-wrapper';
 import { Provider, TransactionReceiptWithDecodedLogs, TxDataPayable } from 'ethereum-types';
@@ -12,209 +11,108 @@ import { formatters } from './formatters';
 import { LogDecoder } from './log_decoder';
 import { MarketSellOrders } from './types';
 
-const DEFAULT_FEE_PROPORTION = 0;
-const PERCENTAGE_DENOMINATOR = 10000;
-const ZERO_AMOUNT = new BigNumber(0);
-const INSUFFICENT_ORDERS_FOR_MAKER_AMOUNT = 'Unable to satisfy makerAssetFillAmount with provided orders';
-
 export class ForwarderWrapper {
     private readonly _web3Wrapper: Web3Wrapper;
     private readonly _forwarderContract: ForwarderContract;
     private readonly _logDecoder: LogDecoder;
-    private readonly _zrxAddress: string;
-    private static _createOptimizedSellOrders(signedOrders: SignedOrder[]): MarketSellOrders {
-        const marketSellOrders = formatters.createMarketSellOrders(signedOrders, ZERO_AMOUNT);
-        const assetDataId = assetDataUtils.decodeAssetProxyId(signedOrders[0].makerAssetData);
-        // Contract will fill this in for us as all of the assetData is assumed to be the same
-        for (let i = 0; i < signedOrders.length; i++) {
-            if (i !== 0 && assetDataId === AssetProxyId.ERC20) {
-                // Forwarding contract will fill this in from the first order
-                marketSellOrders.orders[i].makerAssetData = constants.NULL_BYTES;
+    public static getPercentageOfValue(value: BigNumber, percentage: number): BigNumber {
+        const numerator = constants.PERCENTAGE_DENOMINATOR.times(percentage).dividedToIntegerBy(100);
+        const newValue = value.times(numerator).dividedToIntegerBy(constants.PERCENTAGE_DENOMINATOR);
+        return newValue;
+    }
+    public static getWethForFeeOrders(feeAmount: BigNumber, feeOrders: SignedOrder[]): BigNumber {
+        let wethAmount = new BigNumber(0);
+        let remainingFeeAmount = feeAmount;
+        _.forEach(feeOrders, feeOrder => {
+            const feeAvailable = feeOrder.makerAssetAmount.minus(feeOrder.takerFee);
+            if (!remainingFeeAmount.isZero() && feeAvailable.gt(remainingFeeAmount)) {
+                wethAmount = wethAmount
+                    .plus(feeOrder.takerAssetAmount.times(remainingFeeAmount).dividedToIntegerBy(feeAvailable))
+                    .plus(1);
+                remainingFeeAmount = new BigNumber(0);
+            } else if (!remainingFeeAmount.isZero()) {
+                wethAmount = wethAmount.plus(feeOrder.takerAssetAmount);
+                remainingFeeAmount = remainingFeeAmount.minus(feeAvailable);
             }
-            marketSellOrders.orders[i].takerAssetData = constants.NULL_BYTES;
-        }
-        return marketSellOrders;
+        });
+        return wethAmount;
     }
-    private static _createOptimizedZRXSellOrders(signedOrders: SignedOrder[]): MarketSellOrders {
-        const marketSellOrders = formatters.createMarketSellOrders(signedOrders, ZERO_AMOUNT);
-        // Contract will fill this in for us as all of the assetData is assumed to be the same
-        for (let i = 0; i < signedOrders.length; i++) {
-            marketSellOrders.orders[i].makerAssetData = constants.NULL_BYTES;
-            marketSellOrders.orders[i].takerAssetData = constants.NULL_BYTES;
-        }
-        return marketSellOrders;
+    private static _createOptimizedOrders(signedOrders: SignedOrder[]): MarketSellOrders {
+        _.forEach(signedOrders, (signedOrder, index) => {
+            signedOrder.takerAssetData = constants.NULL_BYTES;
+            if (index > 0) {
+                signedOrder.makerAssetData = constants.NULL_BYTES;
+            }
+        });
+        const params = formatters.createMarketSellOrders(signedOrders, constants.ZERO_AMOUNT);
+        return params;
     }
-    private static _calculateAdditionalFeeProportionAmount(feeProportion: number, fillAmountWei: BigNumber): BigNumber {
-        if (feeProportion > 0) {
-            // Add to the total ETH transaction to ensure all NFTs can be filled after fees
-            // 150 = 1.5% = 0.015
-            const denominator = new BigNumber(1).minus(new BigNumber(feeProportion).dividedBy(PERCENTAGE_DENOMINATOR));
-            return fillAmountWei.dividedBy(denominator).round(0, BigNumber.ROUND_FLOOR);
-        }
-        return fillAmountWei;
+    private static _createOptimizedZrxOrders(signedOrders: SignedOrder[]): MarketSellOrders {
+        _.forEach(signedOrders, signedOrder => {
+            signedOrder.makerAssetData = constants.NULL_BYTES;
+            signedOrder.takerAssetData = constants.NULL_BYTES;
+        });
+        const params = formatters.createMarketSellOrders(signedOrders, constants.ZERO_AMOUNT);
+        return params;
     }
-    constructor(contractInstance: ForwarderContract, provider: Provider, zrxAddress: string) {
+    constructor(contractInstance: ForwarderContract, provider: Provider) {
         this._forwarderContract = contractInstance;
         this._web3Wrapper = new Web3Wrapper(provider);
         this._logDecoder = new LogDecoder(this._web3Wrapper, this._forwarderContract.address);
-        // this._web3Wrapper.abiDecoder.addABI(contractInstance.abi);
-        this._zrxAddress = zrxAddress;
     }
-    public async marketBuyTokensWithEthAsync(
+    public async marketSellOrdersWithEthAsync(
         orders: SignedOrder[],
         feeOrders: SignedOrder[],
-        makerTokenBuyAmount: BigNumber,
         txData: TxDataPayable,
-        opts: { feeProportion?: number; feeRecipient?: string } = {},
+        opts: { feePercentage?: BigNumber; feeRecipient?: string } = {},
     ): Promise<TransactionReceiptWithDecodedLogs> {
-        const params = ForwarderWrapper._createOptimizedSellOrders(orders);
-        const feeParams = ForwarderWrapper._createOptimizedZRXSellOrders(feeOrders);
-        const feeProportion = _.isUndefined(opts.feeProportion) ? DEFAULT_FEE_PROPORTION : opts.feeProportion;
+        const params = ForwarderWrapper._createOptimizedOrders(orders);
+        const feeParams = ForwarderWrapper._createOptimizedZrxOrders(feeOrders);
+        const feePercentage = _.isUndefined(opts.feePercentage) ? constants.ZERO_AMOUNT : opts.feePercentage;
         const feeRecipient = _.isUndefined(opts.feeRecipient) ? constants.NULL_ADDRESS : opts.feeRecipient;
-        const txHash: string = await this._forwarderContract.marketBuyTokensWithEth.sendTransactionAsync(
+        const txHash = await this._forwarderContract.marketSellOrdersWithEth.sendTransactionAsync(
             params.orders,
             params.signatures,
             feeParams.orders,
             feeParams.signatures,
-            makerTokenBuyAmount,
-            feeProportion,
+            feePercentage,
             feeRecipient,
             txData,
         );
         const tx = await this._logDecoder.getTxWithDecodedLogsAsync(txHash);
         return tx;
     }
-    public async marketSellEthForERC20Async(
+    public async marketBuyOrdersWithEthAsync(
         orders: SignedOrder[],
         feeOrders: SignedOrder[],
+        makerAssetFillAmount: BigNumber,
         txData: TxDataPayable,
-        opts: { feeProportion?: number; feeRecipient?: string } = {},
+        opts: { feePercentage?: BigNumber; feeRecipient?: string } = {},
     ): Promise<TransactionReceiptWithDecodedLogs> {
-        const assetDataId = assetDataUtils.decodeAssetProxyId(orders[0].makerAssetData);
-        if (assetDataId !== AssetProxyId.ERC20) {
-            throw new Error('Asset type not supported by marketSellEthForERC20');
-        }
-        const params = ForwarderWrapper._createOptimizedSellOrders(orders);
-        const feeParams = ForwarderWrapper._createOptimizedZRXSellOrders(feeOrders);
-        const feeProportion = _.isUndefined(opts.feeProportion) ? DEFAULT_FEE_PROPORTION : opts.feeProportion;
+        const params = ForwarderWrapper._createOptimizedOrders(orders);
+        const feeParams = ForwarderWrapper._createOptimizedZrxOrders(feeOrders);
+        const feePercentage = _.isUndefined(opts.feePercentage) ? constants.ZERO_AMOUNT : opts.feePercentage;
         const feeRecipient = _.isUndefined(opts.feeRecipient) ? constants.NULL_ADDRESS : opts.feeRecipient;
-        const txHash: string = await this._forwarderContract.marketSellEthForERC20.sendTransactionAsync(
+        const txHash = await this._forwarderContract.marketBuyOrdersWithEth.sendTransactionAsync(
             params.orders,
+            makerAssetFillAmount,
             params.signatures,
             feeParams.orders,
             feeParams.signatures,
-            feeProportion,
+            feePercentage,
             feeRecipient,
             txData,
         );
         const tx = await this._logDecoder.getTxWithDecodedLogsAsync(txHash);
         return tx;
     }
-    public async calculateMarketBuyFillAmountWeiAsync(
-        orders: SignedOrder[],
-        feeOrders: SignedOrder[],
-        feeProportion: number,
-        makerAssetFillAmount: BigNumber,
-    ): Promise<BigNumber> {
-        const assetProxyId = assetDataUtils.decodeAssetProxyId(orders[0].makerAssetData);
-        switch (assetProxyId) {
-            case AssetProxyId.ERC20: {
-                const fillAmountWei = this._calculateMarketBuyERC20FillAmountAsync(
-                    orders,
-                    feeOrders,
-                    feeProportion,
-                    makerAssetFillAmount,
-                );
-                return fillAmountWei;
-            }
-            case AssetProxyId.ERC721: {
-                const fillAmountWei = await this._calculateMarketBuyERC721FillAmountAsync(
-                    orders,
-                    feeOrders,
-                    feeProportion,
-                );
-                return fillAmountWei;
-            }
-            default:
-                throw new Error(`Invalid Asset Proxy Id: ${assetProxyId}`);
-        }
-    }
-    private async _calculateMarketBuyERC20FillAmountAsync(
-        orders: SignedOrder[],
-        feeOrders: SignedOrder[],
-        feeProportion: number,
-        makerAssetFillAmount: BigNumber,
-    ): Promise<BigNumber> {
-        const makerAssetData = assetDataUtils.decodeAssetDataOrThrow(orders[0].makerAssetData);
-        const makerAssetToken = makerAssetData.tokenAddress;
-        const params = formatters.createMarketBuyOrders(orders, makerAssetFillAmount);
-
-        let fillAmountWei;
-        if (makerAssetToken === this._zrxAddress) {
-            // If buying ZRX we buy the tokens and fees from the ZRX order in one step
-            const expectedBuyFeeTokensFillResults = await this._forwarderContract.calculateMarketBuyZrxResults.callAsync(
-                params.orders,
-                makerAssetFillAmount,
-            );
-            if (expectedBuyFeeTokensFillResults.makerAssetFilledAmount.lessThan(makerAssetFillAmount)) {
-                throw new Error(INSUFFICENT_ORDERS_FOR_MAKER_AMOUNT);
-            }
-            fillAmountWei = expectedBuyFeeTokensFillResults.takerAssetFilledAmount;
-        } else {
-            const expectedMarketBuyFillResults = await this._forwarderContract.calculateMarketBuyResults.callAsync(
-                params.orders,
-                makerAssetFillAmount,
-            );
-            if (expectedMarketBuyFillResults.makerAssetFilledAmount.lessThan(makerAssetFillAmount)) {
-                throw new Error(INSUFFICENT_ORDERS_FOR_MAKER_AMOUNT);
-            }
-            fillAmountWei = expectedMarketBuyFillResults.takerAssetFilledAmount;
-            const expectedFeeAmount = expectedMarketBuyFillResults.takerFeePaid;
-            if (expectedFeeAmount.greaterThan(ZERO_AMOUNT)) {
-                const expectedFeeFillFillAmountWei = await this._calculateMarketBuyERC20FillAmountAsync(
-                    feeOrders,
-                    [],
-                    DEFAULT_FEE_PROPORTION,
-                    expectedFeeAmount,
-                );
-                fillAmountWei = fillAmountWei.plus(expectedFeeFillFillAmountWei);
-            }
-        }
-        fillAmountWei = ForwarderWrapper._calculateAdditionalFeeProportionAmount(feeProportion, fillAmountWei);
-        return fillAmountWei;
-    }
-    private async _calculateMarketBuyERC721FillAmountAsync(
-        orders: SignedOrder[],
-        feeOrders: SignedOrder[],
-        feeProportion: number,
-    ): Promise<BigNumber> {
-        // Total cost when buying ERC721 is the total cost of all ERC721 orders + any fee abstraction
-        let fillAmountWei = _.reduce(
-            orders,
-            (totalAmount: BigNumber, order: SignedOrder) => {
-                return totalAmount.plus(order.takerAssetAmount);
-            },
-            ZERO_AMOUNT,
-        );
-        const totalFees = _.reduce(
-            orders,
-            (totalAmount: BigNumber, order: SignedOrder) => {
-                return totalAmount.plus(order.takerFee);
-            },
-            ZERO_AMOUNT,
-        );
-        if (totalFees.greaterThan(ZERO_AMOUNT)) {
-            // Calculate the ZRX fee abstraction cost
-            const emptyFeeOrders: SignedOrder[] = [];
-            const expectedFeeAmountWei = await this._calculateMarketBuyERC20FillAmountAsync(
-                feeOrders,
-                emptyFeeOrders,
-                DEFAULT_FEE_PROPORTION,
-                totalFees,
-            );
-            fillAmountWei = fillAmountWei.plus(expectedFeeAmountWei);
-        }
-        fillAmountWei = ForwarderWrapper._calculateAdditionalFeeProportionAmount(feeProportion, fillAmountWei);
-        return fillAmountWei;
+    public async withdrawERC20Async(
+        tokenAddress: string,
+        amount: BigNumber,
+        txData: TxDataPayable,
+    ): Promise<TransactionReceiptWithDecodedLogs> {
+        const txHash = await this._forwarderContract.withdrawERC20.sendTransactionAsync(tokenAddress, amount, txData);
+        const tx = await this._logDecoder.getTxWithDecodedLogsAsync(txHash);
+        return tx;
     }
 }