feat: Dutch Auction

8 files changed, 482 insertions, 1 deletions

diff --git a/contracts/core/compiler.json b/contracts/core/compiler.json
index c824e4645..a1a60c71d 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/package.json b/contracts/core/package.json
index b20b0ef3f..457625791 100644
--- a/contracts/core/package.json
+++ b/contracts/core/package.json
@@ -34,7 +34,7 @@
     },
     "config": {
         "abis":
-            "generated-artifacts/@(AssetProxyOwner|DummyERC20Token|DummyERC721Receiver|DummyERC721Token|DummyMultipleReturnERC20Token|DummyNoReturnERC20Token|ERC20Token|ERC20Proxy|ERC721Token|ERC721Proxy|Forwarder|Exchange|ExchangeWrapper|IAssetData|IAssetProxy|InvalidERC721Receiver|MixinAuthorizable|MultiAssetProxy|MultiSigWallet|MultiSigWalletWithTimeLock|OrderValidator|ReentrantERC20Token|TestAssetProxyOwner|TestAssetProxyDispatcher|TestConstants|TestExchangeInternals|TestLibBytes|TestLibs|TestSignatureValidator|TestStaticCallReceiver|Validator|Wallet|Whitelist|WETH9|ZRXToken).json"
+            "generated-artifacts/@(AssetProxyOwner|DummyERC20Token|DummyERC721Receiver|DummyERC721Token|DummyMultipleReturnERC20Token|DummyNoReturnERC20Token|DutchAuction|ERC20Token|ERC20Proxy|ERC721Token|ERC721Proxy|Forwarder|Exchange|ExchangeWrapper|IAssetData|IAssetProxy|InvalidERC721Receiver|MixinAuthorizable|MultiAssetProxy|MultiSigWallet|MultiSigWalletWithTimeLock|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 97c1b6209..8a8c5f4d4 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';
@@ -45,6 +46,7 @@ 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 9ca676b56..e9e3f4e79 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/utils/types.ts b/contracts/core/test/utils/types.ts
index 9fc9e1570..d738fcd4e 100644
--- a/contracts/core/test/utils/types.ts
+++ b/contracts/core/test/utils/types.ts
@@ -86,6 +86,7 @@ export enum ContractName {
     ZRXToken = 'ZRXToken',
     DummyERC20Token = 'DummyERC20Token',
     EtherToken = 'WETH9',
+    DutchAuction = 'DutchAuction',
     AssetProxyOwner = 'AssetProxyOwner',
     AccountLevels = 'AccountLevels',
     EtherDelta = 'EtherDelta',
diff --git a/contracts/core/tsconfig.json b/contracts/core/tsconfig.json
index e0f85079a..23b069110 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/packages/contracts/contracts/extensions/DutchAuction/DutchAuction.sol b/packages/contracts/contracts/extensions/DutchAuction/DutchAuction.sol
new file mode 100644
index 000000000..ed4158c25
--- /dev/null
+++ b/packages/contracts/contracts/extensions/DutchAuction/DutchAuction.sol
@@ -0,0 +1,160 @@
+/*
+
+  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";
+
+
+contract DutchAuction {
+    using LibBytes for bytes;
+
+    // solhint-disable var-name-mixedcase
+    IExchange internal EXCHANGE;
+
+    struct AuctionDetails {
+        uint256 beginTime;    // Auction begin time in seconds
+        uint256 endTime;      // Auction end time in seconds
+        uint256 beginPrice;   // Auction begin price
+        uint256 endPrice;     // Auction end price
+        uint256 currentPrice; // Current auction price at block.timestamp
+        uint256 currentTime;  // block.timestamp
+    }
+
+    constructor (address _exchange)
+        public
+    {
+        EXCHANGE = IExchange(_exchange);
+    }
+
+    /// @dev Packs the begin time and price parameters of an auction into uint256.
+    ///      This is stored as the salt value of the sale order.
+    /// @param beginTime Begin time of the auction (32 bits)
+    /// @param beginPrice Starting price of the auction (224 bits)
+    /// @return Encoded Auction Parameters packed into a uint256
+    function encodeParameters(
+        uint256 beginTime,
+        uint256 beginPrice
+    )
+        external
+        view
+        returns (uint256 encodedParameters)
+    {
+        require(beginTime <= 2**32, "INVALID_BEGIN_TIME");
+        require(beginPrice <= 2**224, "INVALID_BEGIN_PRICE");
+        encodedParameters = beginTime;
+        encodedParameters |= beginPrice<<32;
+        return encodedParameters;
+    }
+
+    /// @dev Performs a match of the two orders at the price point given the current block time and the auction
+    ///      start time (encoded in the salt).
+    ///      The Sellers order is a signed order at the lowest price at the end of the auction. Excess from the match
+    ///      is transferred to the seller.
+    /// @param buyOrder The Buyer's order
+    /// @param sellOrder The Seller's order
+    /// @param buySignature Proof that order was created by the left maker.
+    /// @param sellSignature Proof that order was created by the right maker.
+    /// @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
+        // solhint-disable-next-line not-rely-on-time
+        require(block.timestamp >= auctionDetails.beginTime, "AUCTION_NOT_STARTED");
+        // Ensure the auction has not expired. This will fail later in 0x but we can save gas by failing early
+        // solhint-disable-next-line not-rely-on-time
+        require(sellOrder.expirationTimeSeconds > block.timestamp, "AUCTION_EXPIRED");
+        // Ensure the auction goes from high to low
+        require(auctionDetails.beginPrice > auctionDetails.endPrice, "INVALID_PRICE");
+        // Validate the buyer amount is greater than the current auction price
+        require(buyOrder.makerAssetAmount >= auctionDetails.currentPrice, "INVALID_PRICE");
+        // Match orders, maximally filling `buyOrder`
+        matchedFillResults = EXCHANGE.matchOrders(
+            buyOrder,
+            sellOrder,
+            buySignature,
+            sellSignature
+        );
+        // Return any spread to the seller
+        uint256 leftMakerAssetSpreadAmount = matchedFillResults.leftMakerAssetSpreadAmount;
+        if (leftMakerAssetSpreadAmount > 0) {
+            bytes memory assetData = sellOrder.takerAssetData;
+            address token = assetData.readAddress(16);
+            address makerAddress = sellOrder.makerAddress;
+            IERC20Token(token).transfer(makerAddress, leftMakerAssetSpreadAmount);
+        }
+        return matchedFillResults;
+    }
+
+    /// @dev Decodes the packed parameters into beginTime and beginPrice.
+    /// @param encodedParameters the encoded parameters
+    /// @return beginTime and beginPrice decoded
+    function decodeParameters(
+        uint256 encodedParameters
+    )
+        public
+        view
+        returns (uint256 beginTime, uint256 beginPrice)
+    {
+        beginTime = encodedParameters & 0x00000000000000000000000fffffffff;
+        beginPrice = encodedParameters>>32;
+        return (beginTime, beginPrice);
+    }
+
+    /// @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)
+    {
+        // solhint-disable-next-line indent
+        (uint256 auctionBeginTimeSeconds, uint256 auctionBeginPrice) = decodeParameters(order.salt);
+        require(order.expirationTimeSeconds > auctionBeginTimeSeconds, "INVALID_BEGIN_TIME");
+        uint256 auctionDurationSeconds = order.expirationTimeSeconds-auctionBeginTimeSeconds;
+        // solhint-disable-next-line not-rely-on-time
+        uint256 currentDurationSeconds = order.expirationTimeSeconds-block.timestamp;
+        uint256 minPrice = order.takerAssetAmount;
+        uint256 priceDiff = auctionBeginPrice-minPrice;
+        uint256 currentPrice = minPrice + (currentDurationSeconds*priceDiff/auctionDurationSeconds);
+
+        auctionDetails.beginTime = auctionBeginTimeSeconds;
+        auctionDetails.endTime = order.expirationTimeSeconds;
+        auctionDetails.beginPrice = auctionBeginPrice;
+        auctionDetails.endPrice = minPrice;
+        auctionDetails.currentPrice = currentPrice;
+        // solhint-disable-next-line not-rely-on-time
+        auctionDetails.currentTime = block.timestamp;
+
+        return auctionDetails;
+    }
+}
diff --git a/packages/contracts/test/extensions/dutch_auction.ts b/packages/contracts/test/extensions/dutch_auction.ts
new file mode 100644
index 000000000..c61faf9d7
--- /dev/null
+++ b/packages/contracts/test/extensions/dutch_auction.ts
@@ -0,0 +1,315 @@
+import { BlockchainLifecycle } from '@0x/dev-utils';
+import { assetDataUtils } from '@0x/order-utils';
+import { SignedOrder } from '@0x/types';
+import { BigNumber } from '@0x/utils';
+import { Web3Wrapper } from '@0x/web3-wrapper';
+import * as chai from 'chai';
+
+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 weth: DummyERC20TokenContract;
+    let zrxToken: DummyERC20TokenContract;
+    let erc20TokenA: DummyERC20TokenContract;
+    let erc721Token: DummyERC721TokenContract;
+    let dutchAuctionContract: DutchAuctionContract;
+    let wethContract: WETH9Contract;
+    let exchangeWrapper: ExchangeWrapper;
+
+    let sellerOrderFactory: OrderFactory;
+    let buyerOrderFactory: OrderFactory;
+    let erc20Wrapper: ERC20Wrapper;
+    let erc20Balances: ERC20BalancesByOwner;
+    let tenMinutesInSeconds: number;
+    let currentBlockTimestamp: number;
+    let auctionBeginTime: BigNumber;
+    let auctionBeginPrice: BigNumber;
+    let encodedParams: BigNumber;
+    let sellOrder: SignedOrder;
+    let buyOrder: SignedOrder;
+    let erc721MakerAssetIds: BigNumber[];
+
+    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);
+        weth = new DummyERC20TokenContract(wethContract.abi, wethContract.address, provider);
+        erc20Wrapper.addDummyTokenContract(weth);
+
+        const zrxAssetData = assetDataUtils.encodeERC20AssetData(zrxToken.address);
+        const exchangeInstance = await ExchangeContract.deployFrom0xArtifactAsync(
+            artifacts.Exchange,
+            provider,
+            txDefaults,
+            zrxAssetData,
+        );
+        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);
+        tenMinutesInSeconds = 10 * 60;
+        currentBlockTimestamp = await getLatestBlockTimestampAsync();
+        auctionBeginTime = new BigNumber(currentBlockTimestamp).minus(tenMinutesInSeconds);
+        auctionBeginPrice = Web3Wrapper.toBaseUnitAmount(new BigNumber(10), DECIMALS_DEFAULT);
+        encodedParams = await dutchAuctionContract.encodeParameters.callAsync(auctionBeginTime, auctionBeginPrice);
+
+        const sellerDefaultOrderParams = {
+            salt: encodedParams, // Set the encoded params as the salt for the seller order
+            exchangeAddress: exchangeInstance.address,
+            makerAddress,
+            feeRecipientAddress,
+            senderAddress: dutchAuctionContract.address,
+            makerAssetData: assetDataUtils.encodeERC20AssetData(defaultMakerAssetAddress),
+            takerAssetData: assetDataUtils.encodeERC20AssetData(defaultTakerAssetAddress),
+            makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(200), DECIMALS_DEFAULT),
+            takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(2), DECIMALS_DEFAULT),
+            makerFee: Web3Wrapper.toBaseUnitAmount(new BigNumber(0), DECIMALS_DEFAULT),
+            takerFee: Web3Wrapper.toBaseUnitAmount(new BigNumber(0), DECIMALS_DEFAULT),
+        };
+        const buyerDefaultOrderParams = {
+            ...sellerDefaultOrderParams,
+            makerAddress: takerAddress,
+            makerAssetData: sellerDefaultOrderParams.takerAssetData,
+            takerAssetData: sellerDefaultOrderParams.makerAssetData,
+            makerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(10), DECIMALS_DEFAULT),
+            takerAssetAmount: Web3Wrapper.toBaseUnitAmount(new BigNumber(200), DECIMALS_DEFAULT),
+        };
+        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();
+        tenMinutesInSeconds = 10 * 60;
+        currentBlockTimestamp = await getLatestBlockTimestampAsync();
+        auctionBeginTime = new BigNumber(currentBlockTimestamp).minus(tenMinutesInSeconds);
+        auctionBeginPrice = Web3Wrapper.toBaseUnitAmount(new BigNumber(10), DECIMALS_DEFAULT);
+        encodedParams = await dutchAuctionContract.encodeParameters.callAsync(auctionBeginTime, auctionBeginPrice);
+        sellOrder = await sellerOrderFactory.newSignedOrderAsync();
+        buyOrder = await buyerOrderFactory.newSignedOrderAsync();
+    });
+    afterEach(async () => {
+        await blockchainLifecycle.revertAsync();
+    });
+    describe('matchOrders', () => {
+        it('should encode and decode parameters', async () => {
+            const [decodedBegin, decodedBeginPrice] = await dutchAuctionContract.decodeParameters.callAsync(
+                encodedParams,
+            );
+            expect(decodedBegin).to.be.bignumber.equal(auctionBeginTime);
+            expect(decodedBeginPrice).to.be.bignumber.equal(auctionBeginPrice);
+        });
+        it('should be worth the begin price at the begining of the auction', async () => {
+            // TODO this is flakey
+            currentBlockTimestamp = await web3Wrapper.getBlockTimestampAsync('latest');
+            await web3Wrapper.increaseTimeAsync(1);
+            auctionBeginTime = new BigNumber(currentBlockTimestamp + 2);
+            encodedParams = await dutchAuctionContract.encodeParameters.callAsync(auctionBeginTime, auctionBeginPrice);
+            sellOrder = await sellerOrderFactory.newSignedOrderAsync({
+                salt: encodedParams,
+            });
+            const auctionDetails = await dutchAuctionContract.getAuctionDetails.callAsync(sellOrder);
+            expect(auctionDetails.currentPrice).to.be.bignumber.equal(auctionBeginPrice);
+            expect(auctionDetails.beginPrice).to.be.bignumber.equal(auctionBeginPrice);
+        });
+        it('should match orders and send excess to seller', async () => {
+            const txHash = await dutchAuctionContract.matchOrders.sendTransactionAsync(
+                buyOrder,
+                sellOrder,
+                buyOrder.signature,
+                sellOrder.signature,
+                {
+                    from: takerAddress,
+                },
+            );
+            await web3Wrapper.awaitTransactionSuccessAsync(txHash);
+            const newBalances = await erc20Wrapper.getBalancesAsync();
+            expect(newBalances[dutchAuctionContract.address][weth.address]).to.be.bignumber.equal(
+                constants.ZERO_AMOUNT,
+            );
+            expect(newBalances[makerAddress][weth.address]).to.be.bignumber.equal(
+                erc20Balances[makerAddress][weth.address].plus(buyOrder.makerAssetAmount),
+            );
+        });
+        it('should have valid getAuctionDetails at a block in the future', async () => {
+            let auctionDetails = await dutchAuctionContract.getAuctionDetails.callAsync(sellOrder);
+            const beforePrice = auctionDetails.currentPrice;
+            // Increase block time
+            await web3Wrapper.increaseTimeAsync(60);
+            auctionDetails = await dutchAuctionContract.getAuctionDetails.callAsync(sellOrder);
+            const currentPrice = auctionDetails.currentPrice;
+            expect(beforePrice).to.be.bignumber.greaterThan(currentPrice);
+            buyOrder = await buyerOrderFactory.newSignedOrderAsync({
+                makerAssetAmount: currentPrice,
+            });
+            const txHash = await dutchAuctionContract.matchOrders.sendTransactionAsync(
+                buyOrder,
+                sellOrder,
+                buyOrder.signature,
+                sellOrder.signature,
+                {
+                    from: takerAddress,
+                },
+            );
+            await web3Wrapper.awaitTransactionSuccessAsync(txHash);
+            const newBalances = await erc20Wrapper.getBalancesAsync();
+            expect(newBalances[makerAddress][weth.address]).to.be.bignumber.equal(
+                erc20Balances[makerAddress][weth.address].plus(currentPrice),
+            );
+        });
+        it('should revert when auction expires', async () => {
+            // Increase block time
+            await web3Wrapper.increaseTimeAsync(tenMinutesInSeconds);
+            return expectTransactionFailedAsync(
+                dutchAuctionContract.matchOrders.sendTransactionAsync(
+                    buyOrder,
+                    sellOrder,
+                    buyOrder.signature,
+                    sellOrder.signature,
+                    {
+                        from: takerAddress,
+                    },
+                ),
+                'AUCTION_EXPIRED' as any,
+            );
+        });
+        it('cannot be filled for less than the current price', async () => {
+            // Increase block time
+            await web3Wrapper.increaseTimeAsync(60);
+            buyOrder = await buyerOrderFactory.newSignedOrderAsync({
+                makerAssetAmount: sellOrder.takerAssetAmount,
+            });
+            return expectTransactionFailedAsync(
+                dutchAuctionContract.matchOrders.sendTransactionAsync(
+                    buyOrder,
+                    sellOrder,
+                    buyOrder.signature,
+                    sellOrder.signature,
+                    {
+                        from: takerAddress,
+                    },
+                ),
+                'INVALID_PRICE' as any,
+            );
+        });
+        describe('ERC721', () => {
+            it('should match orders when ERC721', async () => {
+                const makerAssetId = erc721MakerAssetIds[0];
+                sellOrder = await sellerOrderFactory.newSignedOrderAsync({
+                    makerAssetAmount: new BigNumber(1),
+                    makerAssetData: assetDataUtils.encodeERC721AssetData(erc721Token.address, makerAssetId),
+                });
+                buyOrder = await buyerOrderFactory.newSignedOrderAsync({
+                    takerAssetAmount: new BigNumber(1),
+                    takerAssetData: assetDataUtils.encodeERC721AssetData(erc721Token.address, makerAssetId),
+                });
+                const txHash = await dutchAuctionContract.matchOrders.sendTransactionAsync(
+                    buyOrder,
+                    sellOrder,
+                    buyOrder.signature,
+                    sellOrder.signature,
+                    {
+                        from: takerAddress,
+                    },
+                );
+                await web3Wrapper.awaitTransactionSuccessAsync(txHash);
+                const newBalances = await erc20Wrapper.getBalancesAsync();
+                expect(newBalances[makerAddress][weth.address]).to.be.bignumber.equal(
+                    erc20Balances[makerAddress][weth.address].plus(buyOrder.makerAssetAmount),
+                );
+                const newOwner = await erc721Token.ownerOf.callAsync(makerAssetId);
+                expect(newOwner).to.be.bignumber.equal(takerAddress);
+            });
+        });
+    });
+});