Merge pull request #568 from 0xProject/bug/0x.js/trade-simulator-trading-zrx

Execute Taker side in trade simulation

packages/0x.js/src/utils/exchange_transfer_simulator.ts

@@ -5,6 +5,7 @@ import * as _ from 'lodash';
 import { TokenWrapper } from '../contract_wrappers/token_wrapper';
 import { BalanceAndProxyAllowanceLazyStore } from '../stores/balance_proxy_allowance_lazy_store';
 import { ExchangeContractErrs, TradeSide, TransferType } from '../types';
+import { constants } from '../utils/constants';
 
 enum FailureReason {
     Balance = 'balance',
@@ -66,6 +67,13 @@ export class ExchangeTransferSimulator {
         tradeSide: TradeSide,
         transferType: TransferType,
     ): Promise<void> {
+        // HACK: When simulating an open order (e.g taker is NULL_ADDRESS), we don't want to adjust balances/
+        // allowances for the taker. We do however, want to increase the balance of the maker since the maker
+        // might be relying on those funds to fill subsequent orders or pay the order's fees.
+        if (from === constants.NULL_ADDRESS && tradeSide === TradeSide.Taker) {
+            await this._increaseBalanceAsync(tokenAddress, to, amountInBaseUnits);
+            return;
+        }
         const balance = await this._store.getBalanceAsync(tokenAddress, from);
         const proxyAllowance = await this._store.getProxyAllowanceAsync(tokenAddress, from);
         if (proxyAllowance.lessThan(amountInBaseUnits)) {

packages/0x.js/src/utils/order_validation_utils.ts

@@ -124,31 +124,12 @@ export class OrderValidationUtils {
         if (!_.isUndefined(expectedFillTakerTokenAmount)) {
             fillTakerTokenAmount = expectedFillTakerTokenAmount;
         }
-        const fillMakerTokenAmount = OrderValidationUtils._getPartialAmount(
+        await OrderValidationUtils.validateFillOrderBalancesAllowancesThrowIfInvalidAsync(
+            exchangeTradeEmulator,
+            signedOrder,
             fillTakerTokenAmount,
-            signedOrder.takerTokenAmount,
-            signedOrder.makerTokenAmount,
-        );
-        await exchangeTradeEmulator.transferFromAsync(
-            signedOrder.makerTokenAddress,
-            signedOrder.maker,
             signedOrder.taker,
-            fillMakerTokenAmount,
-            TradeSide.Maker,
-            TransferType.Trade,
-        );
-        const makerFeeAmount = OrderValidationUtils._getPartialAmount(
-            fillTakerTokenAmount,
-            signedOrder.takerTokenAmount,
-            signedOrder.makerFee,
-        );
-        await exchangeTradeEmulator.transferFromAsync(
             zrxTokenAddress,
-            signedOrder.maker,
-            signedOrder.feeRecipient,
-            makerFeeAmount,
-            TradeSide.Maker,
-            TransferType.Fee,
         );
     }
     public async validateFillOrderThrowIfInvalidAsync(

packages/0x.js/test/order_validation_test.ts

@@ -68,6 +68,40 @@ describe('OrderValidation', () => {
             );
             await zeroEx.exchange.validateOrderFillableOrThrowAsync(signedOrder);
         });
+        it('should succeed if the maker is buying ZRX and has no ZRX balance', async () => {
+            const makerFee = new BigNumber(2);
+            const takerFee = new BigNumber(2);
+            const signedOrder = await fillScenarios.createFillableSignedOrderWithFeesAsync(
+                makerTokenAddress,
+                zrxTokenAddress,
+                makerFee,
+                takerFee,
+                makerAddress,
+                takerAddress,
+                fillableAmount,
+                feeRecipient,
+            );
+            const zrxMakerBalance = await zeroEx.token.getBalanceAsync(zrxTokenAddress, makerAddress);
+            await zeroEx.token.transferAsync(zrxTokenAddress, makerAddress, takerAddress, zrxMakerBalance);
+            await zeroEx.exchange.validateOrderFillableOrThrowAsync(signedOrder);
+        });
+        it('should succeed if the maker is buying ZRX and has no ZRX balance and there is no specified taker', async () => {
+            const makerFee = new BigNumber(2);
+            const takerFee = new BigNumber(2);
+            const signedOrder = await fillScenarios.createFillableSignedOrderWithFeesAsync(
+                makerTokenAddress,
+                zrxTokenAddress,
+                makerFee,
+                takerFee,
+                makerAddress,
+                constants.NULL_ADDRESS,
+                fillableAmount,
+                feeRecipient,
+            );
+            const zrxMakerBalance = await zeroEx.token.getBalanceAsync(zrxTokenAddress, makerAddress);
+            await zeroEx.token.transferAsync(zrxTokenAddress, makerAddress, takerAddress, zrxMakerBalance);
+            await zeroEx.exchange.validateOrderFillableOrThrowAsync(signedOrder);
+        });
         it('should succeed if the order is asymmetric and fillable', async () => {
             const makerFillableAmount = fillableAmount;
             const takerFillableAmount = fillableAmount.minus(4);
@@ -469,4 +503,4 @@ describe('OrderValidation', () => {
             expect(partialTakerFee).to.be.bignumber.equal(takerPartialFee);
         });
     });
-});
+}); // tslint:disable-line:max-file-line-count