Update tests and utils

1 files changed, 35 insertions, 0 deletions

diff --git a/packages/contracts/src/utils/transaction_factory.ts b/packages/contracts/src/utils/transaction_factory.ts
new file mode 100644
index 000000000..3a4f48330
--- /dev/null
+++ b/packages/contracts/src/utils/transaction_factory.ts
@@ -0,0 +1,35 @@
+import { ZeroEx } from '0x.js';
+import { BigNumber } from '@0xproject/utils';
+import * as ethUtil from 'ethereumjs-util';
+
+import { crypto } from './crypto';
+import { signingUtils } from './signing_utils';
+import { SignatureType, SignedTransaction } from './types';
+
+export class TransactionFactory {
+    private _signer: string;
+    private _exchangeAddress: string;
+    private _privateKey: Buffer;
+    constructor(privateKey: Buffer, exchangeAddress: string) {
+        this._privateKey = privateKey;
+        this._exchangeAddress = exchangeAddress;
+        const signerBuff = ethUtil.privateToAddress(this._privateKey);
+        this._signer = `0x${signerBuff.toString('hex')}`;
+    }
+    public newSignedTransaction(
+        data: string,
+        signatureType: SignatureType = SignatureType.Ecrecover,
+    ): SignedTransaction {
+        const salt = ZeroEx.generatePseudoRandomSalt();
+        const txHash = crypto.solSHA3([this._exchangeAddress, salt, ethUtil.toBuffer(data)]);
+        const signature = signingUtils.signMessage(txHash, this._privateKey, signatureType);
+        const signedTx = {
+            exchangeAddress: this._exchangeAddress,
+            salt,
+            signer: this._signer,
+            data,
+            signature: `0x${signature.toString('hex')}`,
+        };
+        return signedTx;
+    }
+}