Merge branch 'development' into feature/contracts-monorepo-2

8 files changed, 698 insertions, 1 deletions

diff --git a/contracts/core/compiler.json b/contracts/core/compiler.json
index ea9e43f12..1ffc26b05 100644
--- a/contracts/core/compiler.json
+++ b/contracts/core/compiler.json
@@ -25,6 +25,7 @@
         "DummyERC721Token",
         "DummyMultipleReturnERC20Token",
         "DummyNoReturnERC20Token",
+        "DutchAuction",
         "ERC20Proxy",
         "ERC20Token",
         "ERC721Token",
diff --git a/contracts/core/contracts/extensions/DutchAuction/DutchAuction.sol b/contracts/core/contracts/extensions/DutchAuction/DutchAuction.sol
new file mode 100644
index 000000000..abe8309cf
--- /dev/null
+++ b/contracts/core/contracts/extensions/DutchAuction/DutchAuction.sol
@@ -0,0 +1,205 @@
+/*
+
+  Copyright 2018 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity 0.4.24;
+pragma experimental ABIEncoderV2;
+
+import "../../protocol/Exchange/interfaces/IExchange.sol";
+import "../../protocol/Exchange/libs/LibOrder.sol";
+import "../../tokens/ERC20Token/IERC20Token.sol";
+import "../../utils/LibBytes/LibBytes.sol";
+import "../../utils/SafeMath/SafeMath.sol";
+
+
+contract DutchAuction is
+    SafeMath
+{
+    using LibBytes for bytes;
+
+    // solhint-disable var-name-mixedcase
+    IExchange internal EXCHANGE;
+
+    struct AuctionDetails {
+        uint256 beginTimeSeconds;    // Auction begin unix timestamp: sellOrder.makerAssetData
+        uint256 endTimeSeconds;      // Auction end unix timestamp: sellOrder.expiryTimeSeconds
+        uint256 beginAmount;         // Auction begin amount: sellOrder.makerAssetData
+        uint256 endAmount;           // Auction end amount: sellOrder.takerAssetAmount
+        uint256 currentAmount;       // Calculated amount given block.timestamp
+        uint256 currentTimeSeconds;  // block.timestamp
+    }
+
+    constructor (address _exchange)
+        public
+    {
+        EXCHANGE = IExchange(_exchange);
+    }
+
+    /// @dev Matches the buy and sell orders at an amount given the following: the current block time, the auction
+    ///      start time and the auction begin amount. The sell order is a an order at the lowest amount
+    ///      at the end of the auction. Excess from the match is transferred to the seller.
+    ///      Over time the price moves from beginAmount to endAmount given the current block.timestamp.
+    ///      sellOrder.expiryTimeSeconds is the end time of the auction.
+    ///      sellOrder.takerAssetAmount is the end amount of the auction (lowest possible amount).
+    ///      sellOrder.makerAssetData is the ABI encoded Asset Proxy data with the following data appended
+    ///      buyOrder.makerAssetData is the buyers bid on the auction, must meet the amount for the current block timestamp
+    ///      (uint256 beginTimeSeconds, uint256 beginAmount).
+    ///      This function reverts in the following scenarios:
+    ///         * Auction has not started (auctionDetails.currentTimeSeconds < auctionDetails.beginTimeSeconds)
+    ///         * Auction has expired (auctionDetails.endTimeSeconds < auctionDetails.currentTimeSeconds)
+    ///         * Amount is invalid: Buy order amount is too low (buyOrder.makerAssetAmount < auctionDetails.currentAmount)
+    ///         * Amount is invalid: Invalid begin amount (auctionDetails.beginAmount > auctionDetails.endAmount)
+    ///         * Any failure in the 0x Match Orders
+    /// @param buyOrder The Buyer's order. This order is for the current expected price of the auction.
+    /// @param sellOrder The Seller's order. This order is for the lowest amount (at the end of the auction).
+    /// @param buySignature Proof that order was created by the buyer.
+    /// @param sellSignature Proof that order was created by the seller.
+    /// @return matchedFillResults amounts filled and fees paid by maker and taker of matched orders.
+    function matchOrders(
+        LibOrder.Order memory buyOrder,
+        LibOrder.Order memory sellOrder,
+        bytes memory buySignature,
+        bytes memory sellSignature
+    )
+        public
+        returns (LibFillResults.MatchedFillResults memory matchedFillResults)
+    {
+        AuctionDetails memory auctionDetails = getAuctionDetails(sellOrder);
+        // Ensure the auction has not yet started
+        require(
+            auctionDetails.currentTimeSeconds >= auctionDetails.beginTimeSeconds,
+            "AUCTION_NOT_STARTED"
+        );
+        // Ensure the auction has not expired. This will fail later in 0x but we can save gas by failing early
+        require(
+            sellOrder.expirationTimeSeconds > auctionDetails.currentTimeSeconds,
+            "AUCTION_EXPIRED"
+        );
+        // Validate the buyer amount is greater than the current auction amount
+        require(
+            buyOrder.makerAssetAmount >= auctionDetails.currentAmount,
+            "INVALID_AMOUNT"
+        );
+        // Match orders, maximally filling `buyOrder`
+        matchedFillResults = EXCHANGE.matchOrders(
+            buyOrder,
+            sellOrder,
+            buySignature,
+            sellSignature
+        );
+        // The difference in sellOrder.takerAssetAmount and current amount is given as spread to the matcher
+        // This may include additional spread from the buyOrder.makerAssetAmount and the currentAmount.
+        // e.g currentAmount is 30, sellOrder.takerAssetAmount is 10 and buyOrder.makerAssetamount is 40.
+        // 10 (40-30) is returned to the buyer, 20 (30-10) sent to the seller and 10 has previously
+        // been transferred to the seller during matchOrders
+        uint256 leftMakerAssetSpreadAmount = matchedFillResults.leftMakerAssetSpreadAmount;
+        if (leftMakerAssetSpreadAmount > 0) {
+            // ERC20 Asset data itself is encoded as follows:
+            //
+            // | Area     | Offset | Length  | Contents                            |
+            // |----------|--------|---------|-------------------------------------|
+            // | Header   | 0      | 4       | function selector                   |
+            // | Params   |        | 1 * 32  | function parameters:                |
+            // |          | 4      | 12      |   1. token address padding          |
+            // |          | 16     | 20      |   2. token address                  |
+            bytes memory assetData = sellOrder.takerAssetData;
+            address token = assetData.readAddress(16);
+            // Calculate the excess from the buy order. This can occur if the buyer sends in a higher
+            // amount than the calculated current amount
+            uint256 buyerExcessAmount = safeSub(buyOrder.makerAssetAmount, auctionDetails.currentAmount);
+            uint256 sellerExcessAmount = safeSub(leftMakerAssetSpreadAmount, buyerExcessAmount);
+            // Return the difference between auctionDetails.currentAmount and sellOrder.takerAssetAmount
+            // to the seller
+            if (sellerExcessAmount > 0) {
+                IERC20Token(token).transfer(sellOrder.makerAddress, sellerExcessAmount);
+            }
+            // Return the difference between buyOrder.makerAssetAmount and auctionDetails.currentAmount
+            // to the buyer
+            if (buyerExcessAmount > 0) {
+                IERC20Token(token).transfer(buyOrder.makerAddress, buyerExcessAmount);
+            }
+        }
+        return matchedFillResults;
+    }
+
+    /// @dev Calculates the Auction Details for the given order
+    /// @param order The sell order
+    /// @return AuctionDetails
+    function getAuctionDetails(
+        LibOrder.Order memory order
+    )
+        public
+        returns (AuctionDetails memory auctionDetails)
+    {
+        uint256 makerAssetDataLength = order.makerAssetData.length;
+        // It is unknown the encoded data of makerAssetData, we assume the last 64 bytes
+        // are the Auction Details encoding.
+        // Auction Details is encoded as follows:
+        //
+        // | Area     | Offset | Length  | Contents                            |
+        // |----------|--------|---------|-------------------------------------|
+        // | Params   |        | 2 * 32  | parameters:                         |
+        // |          | -64    | 32      |   1. auction begin unix timestamp   |
+        // |          | -32    | 32      |   2. auction begin begin amount     |
+        // ERC20 asset data length is 4+32, 64 for auction details results in min length 100
+        require(
+            makerAssetDataLength >= 100,
+            "INVALID_ASSET_DATA"
+        );
+        uint256 auctionBeginTimeSeconds = order.makerAssetData.readUint256(makerAssetDataLength - 64);
+        uint256 auctionBeginAmount = order.makerAssetData.readUint256(makerAssetDataLength - 32);
+        // Ensure the auction has a valid begin time
+        require(
+            order.expirationTimeSeconds > auctionBeginTimeSeconds,
+            "INVALID_BEGIN_TIME"
+        );
+        uint256 auctionDurationSeconds = order.expirationTimeSeconds-auctionBeginTimeSeconds;
+        // Ensure the auction goes from high to low
+        uint256 minAmount = order.takerAssetAmount;
+        require(
+            auctionBeginAmount > minAmount,
+            "INVALID_AMOUNT"
+        );
+        uint256 amountDelta = auctionBeginAmount-minAmount;
+        // solhint-disable-next-line not-rely-on-time
+        uint256 timestamp = block.timestamp;
+        auctionDetails.beginTimeSeconds = auctionBeginTimeSeconds;
+        auctionDetails.endTimeSeconds = order.expirationTimeSeconds;
+        auctionDetails.beginAmount = auctionBeginAmount;
+        auctionDetails.endAmount = minAmount;
+        auctionDetails.currentTimeSeconds = timestamp;
+
+        uint256 remainingDurationSeconds = order.expirationTimeSeconds-timestamp;
+        if (timestamp < auctionBeginTimeSeconds) {
+            // If the auction has not yet begun the current amount is the auctionBeginAmount
+            auctionDetails.currentAmount = auctionBeginAmount;
+        } else if (timestamp >= order.expirationTimeSeconds) {
+            // If the auction has ended the current amount is the minAmount.
+            // Auction end time is guaranteed by 0x Exchange due to the order expiration
+            auctionDetails.currentAmount = minAmount;
+        } else {
+            auctionDetails.currentAmount = safeAdd(
+                minAmount,
+                safeDiv(
+                    safeMul(remainingDurationSeconds, amountDelta),
+                    auctionDurationSeconds
+                )
+            );
+        }
+        return auctionDetails;
+    }
+}
diff --git a/contracts/core/package.json b/contracts/core/package.json
index b1249a4b0..504f479bf 100644
--- a/contracts/core/package.json
+++ b/contracts/core/package.json
@@ -33,7 +33,7 @@
         "lint-contracts": "solhint contracts/**/**/**/**/*.sol"
     },
     "config": {
-        "abis": "generated-artifacts/@(AssetProxyOwner|DummyERC20Token|DummyERC721Receiver|DummyERC721Token|DummyMultipleReturnERC20Token|DummyNoReturnERC20Token|ERC20Token|ERC20Proxy|ERC721Token|ERC721Proxy|Forwarder|Exchange|ExchangeWrapper|IAssetData|IAssetProxy|InvalidERC721Receiver|MixinAuthorizable|MultiAssetProxy|OrderValidator|ReentrantERC20Token|TestAssetProxyOwner|TestAssetProxyDispatcher|TestConstants|TestExchangeInternals|TestLibBytes|TestLibs|TestSignatureValidator|TestStaticCallReceiver|Validator|Wallet|Whitelist|WETH9|ZRXToken).json"
+        "abis": "generated-artifacts/@(AssetProxyOwner|DummyERC20Token|DummyERC721Receiver|DummyERC721Token|DummyMultipleReturnERC20Token|DummyNoReturnERC20Token|DutchAuction|ERC20Token|ERC20Proxy|ERC721Token|ERC721Proxy|Forwarder|Exchange|ExchangeWrapper|IAssetData|IAssetProxy|InvalidERC721Receiver|MixinAuthorizable|MultiAssetProxy|OrderValidator|ReentrantERC20Token|TestAssetProxyOwner|TestAssetProxyDispatcher|TestConstants|TestExchangeInternals|TestLibBytes|TestLibs|TestSignatureValidator|TestStaticCallReceiver|Validator|Wallet|Whitelist|WETH9|ZRXToken).json"
     },
     "repository": {
         "type": "git",
diff --git a/contracts/core/src/artifacts/index.ts b/contracts/core/src/artifacts/index.ts
index e2161f3f9..f217adb8e 100644
--- a/contracts/core/src/artifacts/index.ts
+++ b/contracts/core/src/artifacts/index.ts
@@ -6,6 +6,7 @@ import * as DummyERC721Receiver from '../../generated-artifacts/DummyERC721Recei
 import * as DummyERC721Token from '../../generated-artifacts/DummyERC721Token.json';
 import * as DummyMultipleReturnERC20Token from '../../generated-artifacts/DummyMultipleReturnERC20Token.json';
 import * as DummyNoReturnERC20Token from '../../generated-artifacts/DummyNoReturnERC20Token.json';
+import * as DutchAuction from '../../generated-artifacts/DutchAuction.json';
 import * as ERC20Proxy from '../../generated-artifacts/ERC20Proxy.json';
 import * as ERC20Token from '../../generated-artifacts/ERC20Token.json';
 import * as ERC721Proxy from '../../generated-artifacts/ERC721Proxy.json';
@@ -43,6 +44,7 @@ export const artifacts = {
     DummyERC721Token: DummyERC721Token as ContractArtifact,
     DummyMultipleReturnERC20Token: DummyMultipleReturnERC20Token as ContractArtifact,
     DummyNoReturnERC20Token: DummyNoReturnERC20Token as ContractArtifact,
+    DutchAuction: DutchAuction as ContractArtifact,
     ERC20Proxy: ERC20Proxy as ContractArtifact,
     ERC20Token: ERC20Token as ContractArtifact,
     ERC721Proxy: ERC721Proxy as ContractArtifact,
diff --git a/contracts/core/src/wrappers/index.ts b/contracts/core/src/wrappers/index.ts
index 2a73b37ff..06a139209 100644
--- a/contracts/core/src/wrappers/index.ts
+++ b/contracts/core/src/wrappers/index.ts
@@ -4,6 +4,7 @@ export * from '../../generated-wrappers/dummy_erc721_receiver';
 export * from '../../generated-wrappers/dummy_erc721_token';
 export * from '../../generated-wrappers/dummy_multiple_return_erc20_token';
 export * from '../../generated-wrappers/dummy_no_return_erc20_token';
+export * from '../../generated-wrappers/dutch_auction';
 export * from '../../generated-wrappers/erc20_proxy';
 export * from '../../generated-wrappers/erc721_proxy';
 export * from '../../generated-wrappers/erc20_token';
diff --git a/contracts/core/test/extensions/dutch_auction.ts b/contracts/core/test/extensions/dutch_auction.ts
new file mode 100644
index 000000000..c133d8c60
--- /dev/null
+++ b/contracts/core/test/extensions/dutch_auction.ts
@@ -0,0 +1,486 @@
+import { BlockchainLifecycle } from '@0x/dev-utils';
+import { assetDataUtils, generatePseudoRandomSalt } from '@0x/order-utils';
+import { RevertReason, SignedOrder } from '@0x/types';
+import { BigNumber } from '@0x/utils';
+import { Web3Wrapper } from '@0x/web3-wrapper';
+import * as chai from 'chai';
+import ethAbi = require('ethereumjs-abi');
+import * as ethUtil from 'ethereumjs-util';
+import * as _ from 'lodash';
+
+import { DummyERC20TokenContract } from '../../generated-wrappers/dummy_erc20_token';
+import { DummyERC721TokenContract } from '../../generated-wrappers/dummy_erc721_token';
+import { DutchAuctionContract } from '../../generated-wrappers/dutch_auction';
+import { ExchangeContract } from '../../generated-wrappers/exchange';
+import { WETH9Contract } from '../../generated-wrappers/weth9';
+import { artifacts } from '../../src/artifacts';
+import { expectTransactionFailedAsync } from '../utils/assertions';
+import { getLatestBlockTimestampAsync } from '../utils/block_timestamp';
+import { chaiSetup } from '../utils/chai_setup';
+import { constants } from '../utils/constants';
+import { ERC20Wrapper } from '../utils/erc20_wrapper';
+import { ERC721Wrapper } from '../utils/erc721_wrapper';
+import { ExchangeWrapper } from '../utils/exchange_wrapper';
+import { OrderFactory } from '../utils/order_factory';
+import { ContractName, ERC20BalancesByOwner } from '../utils/types';
+import { provider, txDefaults, web3Wrapper } from '../utils/web3_wrapper';
+
+chaiSetup.configure();
+const expect = chai.expect;
+const blockchainLifecycle = new BlockchainLifecycle(web3Wrapper);
+const DECIMALS_DEFAULT = 18;
+
+describe(ContractName.DutchAuction, () => {
+    let makerAddress: string;
+    let owner: string;
+    let takerAddress: string;
+    let feeRecipientAddress: string;
+    let defaultMakerAssetAddress: string;
+
+    let zrxToken: DummyERC20TokenContract;
+    let erc20TokenA: DummyERC20TokenContract;
+    let erc721Token: DummyERC721TokenContract;
+    let dutchAuctionContract: DutchAuctionContract;
+    let wethContract: WETH9Contract;
+
+    let sellerOrderFactory: OrderFactory;
+    let buyerOrderFactory: OrderFactory;
+    let erc20Wrapper: ERC20Wrapper;
+    let erc20Balances: ERC20BalancesByOwner;
+    let currentBlockTimestamp: number;
+    let auctionBeginTimeSeconds: BigNumber;
+    let auctionEndTimeSeconds: BigNumber;
+    let auctionBeginAmount: BigNumber;
+    let auctionEndAmount: BigNumber;
+    let sellOrder: SignedOrder;
+    let buyOrder: SignedOrder;
+    let erc721MakerAssetIds: BigNumber[];
+    const tenMinutesInSeconds = 10 * 60;
+
+    async function increaseTimeAsync(): Promise<void> {
+        const timestampBefore = await getLatestBlockTimestampAsync();
+        await web3Wrapper.increaseTimeAsync(5);
+        const timestampAfter = await getLatestBlockTimestampAsync();
+        // HACK send some transactions when a time increase isn't supported
+        if (timestampAfter === timestampBefore) {
+            await web3Wrapper.sendTransactionAsync({ to: makerAddress, from: makerAddress, value: new BigNumber(1) });
+        }
+    }
+
+    function extendMakerAssetData(makerAssetData: string, beginTimeSeconds: BigNumber, beginAmount: BigNumber): string {
+        return ethUtil.bufferToHex(
+            Buffer.concat([
+                ethUtil.toBuffer(makerAssetData),
+                ethUtil.toBuffer(
+                    (ethAbi as any).rawEncode(
+                        ['uint256', 'uint256'],
+                        [beginTimeSeconds.toString(), beginAmount.toString()],
+                    ),
+                ),
+            ]),
+        );
+    }
+
+    before(async () => {
+        await blockchainLifecycle.startAsync();
+        const accounts = await web3Wrapper.getAvailableAddressesAsync();
+        const usedAddresses = ([owner, makerAddress, takerAddress, feeRecipientAddress] = accounts);
+
+        erc20Wrapper = new ERC20Wrapper(provider, usedAddresses, owner);
+
+        const numDummyErc20ToDeploy = 2;
+        [erc20TokenA, zrxToken] = await erc20Wrapper.deployDummyTokensAsync(
+            numDummyErc20ToDeploy,
+            constants.DUMMY_TOKEN_DECIMALS,
+        );
+        const erc20Proxy = await erc20Wrapper.deployProxyAsync();
+        await erc20Wrapper.setBalancesAndAllowancesAsync();
+
+        const erc721Wrapper = new ERC721Wrapper(provider, usedAddresses, owner);
+        [erc721Token] = await erc721Wrapper.deployDummyTokensAsync();
+        const erc721Proxy = await erc721Wrapper.deployProxyAsync();
+        await erc721Wrapper.setBalancesAndAllowancesAsync();
+        const erc721Balances = await erc721Wrapper.getBalancesAsync();
+        erc721MakerAssetIds = erc721Balances[makerAddress][erc721Token.address];
+
+        wethContract = await WETH9Contract.deployFrom0xArtifactAsync(artifacts.WETH9, provider, txDefaults);
+        erc20Wrapper.addDummyTokenContract(wethContract as any);
+
+        const zrxAssetData = assetDataUtils.encodeERC20AssetData(zrxToken.address);
+        const exchangeInstance = await ExchangeContract.deployFrom0xArtifactAsync(
+            artifacts.Exchange,
+            provider,
+            txDefaults,
+            zrxAssetData,
+        );
+        const exchangeWrapper = new ExchangeWrapper(exchangeInstance, provider);
+        await exchangeWrapper.registerAssetProxyAsync(erc20Proxy.address, owner);
+        await exchangeWrapper.registerAssetProxyAsync(erc721Proxy.address, owner);
+
+        await erc20Proxy.addAuthorizedAddress.sendTransactionAsync(exchangeInstance.address, {
+            from: owner,
+        });
+        await erc721Proxy.addAuthorizedAddress.sendTransactionAsync(exchangeInstance.address, {
+            from: owner,
+        });
+
+        const dutchAuctionInstance = await DutchAuctionContract.deployFrom0xArtifactAsync(
+            artifacts.DutchAuction,
+            provider,
+            txDefaults,
+            exchangeInstance.address,
+        );
+        dutchAuctionContract = new DutchAuctionContract(
+            dutchAuctionInstance.abi,
+            dutchAuctionInstance.address,
+            provider,
+        );
+
+        defaultMakerAssetAddress = erc20TokenA.address;
+        const defaultTakerAssetAddress = wethContract.address;
+
+        // Set up taker WETH balance and allowance
+        await web3Wrapper.awaitTransactionSuccessAsync(
+            await wethContract.deposit.sendTransactionAsync({
+                from: takerAddress,
+                value: Web3Wrapper.toBaseUnitAmount(new BigNumber(50), DECIMALS_DEFAULT),
+            }),
+        );
+        await web3Wrapper.awaitTransactionSuccessAsync(
+            await wethContract.approve.sendTransactionAsync(
+                erc20Proxy.address,
+                constants.UNLIMITED_ALLOWANCE_IN_BASE_UNITS,
+                { from: takerAddress },
+            ),
+        );
+        web3Wrapper.abiDecoder.addABI(exchangeInstance.abi);
+        web3Wrapper.abiDecoder.addABI(zrxToken.abi);
+        erc20Wrapper.addTokenOwnerAddress(dutchAuctionContract.address);
+
+        currentBlockTimestamp = await getLatestBlockTimestampAsync();
+        // Default auction begins 10 minutes ago
+        auctionBeginTimeSeconds = new BigNumber(currentBlockTimestamp).minus(tenMinutesInSeconds);
+        // Default auction ends 10 from now
+        auctionEndTimeSeconds = new BigNumber(currentBlockTimestamp).plus(tenMinutesInSeconds);
+        auctionBeginAmount = Web3Wrapper.toBaseUnitAmount(new BigNumber(10), DECIMALS_DEFAULT);
+        auctionEndAmount = Web3Wrapper.toBaseUnitAmount(new BigNumber(1), DECIMALS_DEFAULT);
+
+        // Default sell order and buy order are exact mirrors
+        const sellerDefaultOrderParams = {
+            salt: generatePseudoRandomSalt(),
+            exchangeAddress: exchangeInstance.address,
+            makerAddress,
+            feeRecipientAddress,
+            // taker address or sender address should be set to the ducth auction contract
+            takerAddress: dutchAuctionContract.address,
+            makerAssetData: extendMakerAssetData(
+                assetDataUtils.encodeERC20AssetData(defaultMakerAssetAddress),
+                auctionBeginTimeSeconds,
+                auctionBeginAmount,
+            ),
+            takerAssetData: assetDataUtils.encodeERC20AssetData(defaultTakerAssetAddress),
+            makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(200), DECIMALS_DEFAULT),
+            takerAssetAmount: auctionEndAmount,
+            expirationTimeSeconds: auctionEndTimeSeconds,
+            makerFee: constants.ZERO_AMOUNT,
+            takerFee: constants.ZERO_AMOUNT,
+        };
+        // Default buy order is for the auction begin price
+        const buyerDefaultOrderParams = {
+            ...sellerDefaultOrderParams,
+            makerAddress: takerAddress,
+            makerAssetData: sellerDefaultOrderParams.takerAssetData,
+            takerAssetData: sellerDefaultOrderParams.makerAssetData,
+            makerAssetAmount: auctionBeginAmount,
+            takerAssetAmount: sellerDefaultOrderParams.makerAssetAmount,
+        };
+        const makerPrivateKey = constants.TESTRPC_PRIVATE_KEYS[accounts.indexOf(makerAddress)];
+        const takerPrivateKey = constants.TESTRPC_PRIVATE_KEYS[accounts.indexOf(takerAddress)];
+        sellerOrderFactory = new OrderFactory(makerPrivateKey, sellerDefaultOrderParams);
+        buyerOrderFactory = new OrderFactory(takerPrivateKey, buyerDefaultOrderParams);
+    });
+    after(async () => {
+        await blockchainLifecycle.revertAsync();
+    });
+    beforeEach(async () => {
+        await blockchainLifecycle.startAsync();
+        erc20Balances = await erc20Wrapper.getBalancesAsync();
+        sellOrder = await sellerOrderFactory.newSignedOrderAsync();
+        buyOrder = await buyerOrderFactory.newSignedOrderAsync();
+    });
+    afterEach(async () => {
+        await blockchainLifecycle.revertAsync();
+    });
+    describe('matchOrders', () => {
+        it('should be worth the begin price at the begining of the auction', async () => {
+            auctionBeginTimeSeconds = new BigNumber(currentBlockTimestamp + 2);
+            sellOrder = await sellerOrderFactory.newSignedOrderAsync({
+                makerAssetData: extendMakerAssetData(
+                    assetDataUtils.encodeERC20AssetData(defaultMakerAssetAddress),
+                    auctionBeginTimeSeconds,
+                    auctionBeginAmount,
+                ),
+            });
+            const auctionDetails = await dutchAuctionContract.getAuctionDetails.callAsync(sellOrder);
+            expect(auctionDetails.currentAmount).to.be.bignumber.equal(auctionBeginAmount);
+            expect(auctionDetails.beginAmount).to.be.bignumber.equal(auctionBeginAmount);
+        });
+        it('should be be worth the end price at the end of the auction', async () => {
+            auctionBeginTimeSeconds = new BigNumber(currentBlockTimestamp - tenMinutesInSeconds * 2);
+            auctionEndTimeSeconds = new BigNumber(currentBlockTimestamp - tenMinutesInSeconds);
+            sellOrder = await sellerOrderFactory.newSignedOrderAsync({
+                makerAssetData: extendMakerAssetData(
+                    assetDataUtils.encodeERC20AssetData(defaultMakerAssetAddress),
+                    auctionBeginTimeSeconds,
+                    auctionBeginAmount,
+                ),
+                expirationTimeSeconds: auctionEndTimeSeconds,
+            });
+            const auctionDetails = await dutchAuctionContract.getAuctionDetails.callAsync(sellOrder);
+            expect(auctionDetails.currentAmount).to.be.bignumber.equal(auctionEndAmount);
+            expect(auctionDetails.beginAmount).to.be.bignumber.equal(auctionBeginAmount);
+        });
+        it('should match orders at current amount and send excess to buyer', async () => {
+            const beforeAuctionDetails = await dutchAuctionContract.getAuctionDetails.callAsync(sellOrder);
+            buyOrder = await buyerOrderFactory.newSignedOrderAsync({
+                makerAssetAmount: beforeAuctionDetails.currentAmount.times(2),
+            });
+            await web3Wrapper.awaitTransactionSuccessAsync(
+                await dutchAuctionContract.matchOrders.sendTransactionAsync(
+                    buyOrder,
+                    sellOrder,
+                    buyOrder.signature,
+                    sellOrder.signature,
+                    {
+                        from: takerAddress,
+                    },
+                ),
+            );
+            const afterAuctionDetails = await dutchAuctionContract.getAuctionDetails.callAsync(sellOrder);
+            const newBalances = await erc20Wrapper.getBalancesAsync();
+            expect(newBalances[dutchAuctionContract.address][wethContract.address]).to.be.bignumber.equal(
+                constants.ZERO_AMOUNT,
+            );
+            // HACK gte used here due to a bug in ganache where the timestamp can change
+            // between multiple calls to the same block. Which can move the amount in our case
+            // ref: https://github.com/trufflesuite/ganache-core/issues/111
+            expect(newBalances[makerAddress][wethContract.address]).to.be.bignumber.gte(
+                erc20Balances[makerAddress][wethContract.address].plus(afterAuctionDetails.currentAmount),
+            );
+            expect(newBalances[takerAddress][wethContract.address]).to.be.bignumber.gte(
+                erc20Balances[takerAddress][wethContract.address].minus(beforeAuctionDetails.currentAmount),
+            );
+        });
+        it('should have valid getAuctionDetails at some block in the future', async () => {
+            let auctionDetails = await dutchAuctionContract.getAuctionDetails.callAsync(sellOrder);
+            const beforeAmount = auctionDetails.currentAmount;
+            await increaseTimeAsync();
+            auctionDetails = await dutchAuctionContract.getAuctionDetails.callAsync(sellOrder);
+            const currentAmount = auctionDetails.currentAmount;
+            expect(beforeAmount).to.be.bignumber.greaterThan(currentAmount);
+
+            buyOrder = await buyerOrderFactory.newSignedOrderAsync({
+                makerAssetAmount: currentAmount,
+            });
+            const txHash = await dutchAuctionContract.matchOrders.sendTransactionAsync(
+                buyOrder,
+                sellOrder,
+                buyOrder.signature,
+                sellOrder.signature,
+                {
+                    from: takerAddress,
+                    // HACK geth seems to miscalculate the gas required intermittently
+                    gas: 400000,
+                },
+            );
+            await web3Wrapper.awaitTransactionSuccessAsync(txHash);
+            const newBalances = await erc20Wrapper.getBalancesAsync();
+            expect(newBalances[makerAddress][wethContract.address]).to.be.bignumber.equal(
+                erc20Balances[makerAddress][wethContract.address].plus(currentAmount),
+            );
+        });
+        it('maker fees on sellOrder are paid to the fee receipient', async () => {
+            sellOrder = await sellerOrderFactory.newSignedOrderAsync({
+                makerFee: new BigNumber(1),
+            });
+            const txHash = await dutchAuctionContract.matchOrders.sendTransactionAsync(
+                buyOrder,
+                sellOrder,
+                buyOrder.signature,
+                sellOrder.signature,
+                {
+                    from: takerAddress,
+                },
+            );
+            await web3Wrapper.awaitTransactionSuccessAsync(txHash);
+            const afterAuctionDetails = await dutchAuctionContract.getAuctionDetails.callAsync(sellOrder);
+            const newBalances = await erc20Wrapper.getBalancesAsync();
+            expect(newBalances[makerAddress][wethContract.address]).to.be.bignumber.gte(
+                erc20Balances[makerAddress][wethContract.address].plus(afterAuctionDetails.currentAmount),
+            );
+            expect(newBalances[feeRecipientAddress][zrxToken.address]).to.be.bignumber.equal(
+                erc20Balances[feeRecipientAddress][zrxToken.address].plus(sellOrder.makerFee),
+            );
+        });
+        it('maker fees on buyOrder are paid to the fee receipient', async () => {
+            buyOrder = await buyerOrderFactory.newSignedOrderAsync({
+                makerFee: new BigNumber(1),
+            });
+            const txHash = await dutchAuctionContract.matchOrders.sendTransactionAsync(
+                buyOrder,
+                sellOrder,
+                buyOrder.signature,
+                sellOrder.signature,
+                {
+                    from: takerAddress,
+                },
+            );
+            await web3Wrapper.awaitTransactionSuccessAsync(txHash);
+            const newBalances = await erc20Wrapper.getBalancesAsync();
+            const afterAuctionDetails = await dutchAuctionContract.getAuctionDetails.callAsync(sellOrder);
+            expect(newBalances[makerAddress][wethContract.address]).to.be.bignumber.gte(
+                erc20Balances[makerAddress][wethContract.address].plus(afterAuctionDetails.currentAmount),
+            );
+            expect(newBalances[feeRecipientAddress][zrxToken.address]).to.be.bignumber.equal(
+                erc20Balances[feeRecipientAddress][zrxToken.address].plus(buyOrder.makerFee),
+            );
+        });
+        it('should revert when auction expires', async () => {
+            auctionBeginTimeSeconds = new BigNumber(currentBlockTimestamp - tenMinutesInSeconds * 2);
+            auctionEndTimeSeconds = new BigNumber(currentBlockTimestamp - tenMinutesInSeconds);
+            sellOrder = await sellerOrderFactory.newSignedOrderAsync({
+                expirationTimeSeconds: auctionEndTimeSeconds,
+                makerAssetData: extendMakerAssetData(
+                    assetDataUtils.encodeERC20AssetData(defaultMakerAssetAddress),
+                    auctionBeginTimeSeconds,
+                    auctionBeginAmount,
+                ),
+            });
+            return expectTransactionFailedAsync(
+                dutchAuctionContract.matchOrders.sendTransactionAsync(
+                    buyOrder,
+                    sellOrder,
+                    buyOrder.signature,
+                    sellOrder.signature,
+                    {
+                        from: takerAddress,
+                    },
+                ),
+                RevertReason.AuctionExpired,
+            );
+        });
+        it('cannot be filled for less than the current price', async () => {
+            await increaseTimeAsync();
+            buyOrder = await buyerOrderFactory.newSignedOrderAsync({
+                makerAssetAmount: sellOrder.takerAssetAmount,
+            });
+            return expectTransactionFailedAsync(
+                dutchAuctionContract.matchOrders.sendTransactionAsync(
+                    buyOrder,
+                    sellOrder,
+                    buyOrder.signature,
+                    sellOrder.signature,
+                    {
+                        from: takerAddress,
+                    },
+                ),
+                RevertReason.AuctionInvalidAmount,
+            );
+        });
+        it('auction begin amount must be higher than final amount ', async () => {
+            sellOrder = await sellerOrderFactory.newSignedOrderAsync({
+                takerAssetAmount: auctionBeginAmount.plus(1),
+            });
+            return expectTransactionFailedAsync(
+                dutchAuctionContract.matchOrders.sendTransactionAsync(
+                    buyOrder,
+                    sellOrder,
+                    buyOrder.signature,
+                    sellOrder.signature,
+                    {
+                        from: takerAddress,
+                    },
+                ),
+                RevertReason.AuctionInvalidAmount,
+            );
+        });
+        it('begin time is less than end time', async () => {
+            auctionBeginTimeSeconds = new BigNumber(auctionEndTimeSeconds).plus(tenMinutesInSeconds);
+            sellOrder = await sellerOrderFactory.newSignedOrderAsync({
+                expirationTimeSeconds: auctionEndTimeSeconds,
+                makerAssetData: extendMakerAssetData(
+                    assetDataUtils.encodeERC20AssetData(defaultMakerAssetAddress),
+                    auctionBeginTimeSeconds,
+                    auctionBeginAmount,
+                ),
+            });
+            return expectTransactionFailedAsync(
+                dutchAuctionContract.matchOrders.sendTransactionAsync(
+                    buyOrder,
+                    sellOrder,
+                    buyOrder.signature,
+                    sellOrder.signature,
+                    {
+                        from: takerAddress,
+                    },
+                ),
+                RevertReason.AuctionInvalidBeginTime,
+            );
+        });
+        it('asset data contains auction parameters', async () => {
+            sellOrder = await sellerOrderFactory.newSignedOrderAsync({
+                makerAssetData: assetDataUtils.encodeERC20AssetData(defaultMakerAssetAddress),
+            });
+            return expectTransactionFailedAsync(
+                dutchAuctionContract.matchOrders.sendTransactionAsync(
+                    buyOrder,
+                    sellOrder,
+                    buyOrder.signature,
+                    sellOrder.signature,
+                    {
+                        from: takerAddress,
+                    },
+                ),
+                RevertReason.InvalidAssetData,
+            );
+        });
+        describe('ERC721', () => {
+            it('should match orders when ERC721', async () => {
+                const makerAssetId = erc721MakerAssetIds[0];
+                sellOrder = await sellerOrderFactory.newSignedOrderAsync({
+                    makerAssetAmount: new BigNumber(1),
+                    makerAssetData: extendMakerAssetData(
+                        assetDataUtils.encodeERC721AssetData(erc721Token.address, makerAssetId),
+                        auctionBeginTimeSeconds,
+                        auctionBeginAmount,
+                    ),
+                });
+                buyOrder = await buyerOrderFactory.newSignedOrderAsync({
+                    takerAssetAmount: new BigNumber(1),
+                    takerAssetData: sellOrder.makerAssetData,
+                });
+                await web3Wrapper.awaitTransactionSuccessAsync(
+                    await dutchAuctionContract.matchOrders.sendTransactionAsync(
+                        buyOrder,
+                        sellOrder,
+                        buyOrder.signature,
+                        sellOrder.signature,
+                        {
+                            from: takerAddress,
+                        },
+                    ),
+                );
+                const afterAuctionDetails = await dutchAuctionContract.getAuctionDetails.callAsync(sellOrder);
+                const newBalances = await erc20Wrapper.getBalancesAsync();
+                // HACK gte used here due to a bug in ganache where the timestamp can change
+                // between multiple calls to the same block. Which can move the amount in our case
+                // ref: https://github.com/trufflesuite/ganache-core/issues/111
+                expect(newBalances[makerAddress][wethContract.address]).to.be.bignumber.gte(
+                    erc20Balances[makerAddress][wethContract.address].plus(afterAuctionDetails.currentAmount),
+                );
+                const newOwner = await erc721Token.ownerOf.callAsync(makerAssetId);
+                expect(newOwner).to.be.bignumber.equal(takerAddress);
+            });
+        });
+    });
+});
diff --git a/contracts/core/tsconfig.json b/contracts/core/tsconfig.json
index be552e5a3..57ab35732 100644
--- a/contracts/core/tsconfig.json
+++ b/contracts/core/tsconfig.json
@@ -13,6 +13,7 @@
         "./generated-artifacts/DummyERC721Token.json",
         "./generated-artifacts/DummyMultipleReturnERC20Token.json",
         "./generated-artifacts/DummyNoReturnERC20Token.json",
+        "./generated-artifacts/DutchAuction.json",
         "./generated-artifacts/ERC20Proxy.json",
         "./generated-artifacts/ERC20Token.json",
         "./generated-artifacts/ERC721Proxy.json",
diff --git a/contracts/test-utils/src/types.ts b/contracts/test-utils/src/types.ts
index 9fc9e1570..d738fcd4e 100644
--- a/contracts/test-utils/src/types.ts
+++ b/contracts/test-utils/src/types.ts
@@ -86,6 +86,7 @@ export enum ContractName {
     ZRXToken = 'ZRXToken',
     DummyERC20Token = 'DummyERC20Token',
     EtherToken = 'WETH9',
+    DutchAuction = 'DutchAuction',
     AssetProxyOwner = 'AssetProxyOwner',
     AccountLevels = 'AccountLevels',
     EtherDelta = 'EtherDelta',