Fix exchange package build

contracts/test-utils/src/transaction_factory.ts

@@ -1,7 +1,9 @@
 import { generatePseudoRandomSalt, transactionHashUtils } from '@0x/order-utils';
 import { SignatureType, SignedZeroExTransaction } from '@0x/types';
+import { BigNumber } from '@0x/utils';
 import * as ethUtil from 'ethereumjs-util';
 
+import { getLatestBlockTimestampAsync } from './block_timestamp';
 import { signingUtils } from './signing_utils';
 
 export class TransactionFactory {
@@ -16,16 +18,19 @@ export class TransactionFactory {
         this._chainId = chainId;
         this._signerBuff = ethUtil.privateToAddress(this._privateKey);
     }
-    public newSignedTransaction(
+    public async newSignedTransactionAsync(
         data: string,
         signatureType: SignatureType = SignatureType.EthSign,
-    ): SignedZeroExTransaction {
+    ): Promise<SignedZeroExTransaction> {
+        const tenMinutesInSeconds = 10 * 60;
+        const currentBlockTimestamp = await getLatestBlockTimestampAsync();
         const salt = generatePseudoRandomSalt();
         const signerAddress = `0x${this._signerBuff.toString('hex')}`;
         const transaction = {
             salt,
             signerAddress,
             data,
+            expirationTimeSeconds: new BigNumber(currentBlockTimestamp).plus(tenMinutesInSeconds),
             domain: {
                 verifyingContractAddress: this._exchangeAddress,
                 chainId: this._chainId,