Working towards maker signature validation

contracts/staking/test/utils/ApprovalFactory.ts

@@ -0,0 +1,42 @@
+import { signingUtils } from '@0x/contracts-test-utils';
+import { SignatureType } from '@0x/types';
+import { BigNumber } from '@0x/utils';
+import * as ethUtil from 'ethereumjs-util';
+
+import { hashUtils } from './hash_utils';
+import { SignedStakingPoolApproval } from './types';
+
+export class ApprovalFactory {
+    private readonly _privateKey: Buffer;
+    private readonly _verifyingContractAddress: string;
+    private readonly _chainId: number;
+
+    constructor(privateKey: Buffer, verifyingContractAddress: string, chainId: number) {
+        this._privateKey = privateKey;
+        this._verifyingContractAddress = verifyingContractAddress;
+        this._chainId = chainId;
+    }
+
+    public newSignedApproval(
+        poolId: string,
+        makerAddress: string,
+        signatureType: SignatureType = SignatureType.EthSign,
+    ): SignedStakingPoolApproval {
+        const approvalHashBuff = hashUtils.getStakingPoolApprovalHashBuffer(
+            poolId,
+            makerAddress,
+            this._verifyingContractAddress,
+            this._chainId
+        );
+        console.log('*** APPROVAL HASH ***\n', approvalHashBuff);
+        const signatureBuff = signingUtils.signMessage(approvalHashBuff, this._privateKey, signatureType);
+        const signedApproval = {
+            makerAddress,
+            poolId,
+            verifyingContractAddress: this._verifyingContractAddress,
+            chainId: this._chainId,
+            signature: ethUtil.addHexPrefix(signatureBuff.toString('hex')),
+        };
+        return signedApproval;
+    }
+}