From 4c8f024e55f0a85a87307169556a7c6e3be1f906 Mon Sep 17 00:00:00 2001
From: CedarMist <134699267+CedarMist@users.noreply.github.com>
Date: Thu, 19 Oct 2023 14:52:05 +0100
Subject: [PATCH] examples/onchain-signer: fixed example to work with docs

---
 examples/onchain-signer/contracts/Gasless.sol | 15 +++++--------
 examples/onchain-signer/test/CommentBox.ts    | 22 +++++++++++++++++--
 2 files changed, 25 insertions(+), 12 deletions(-)

diff --git a/examples/onchain-signer/contracts/Gasless.sol b/examples/onchain-signer/contracts/Gasless.sol
index 03dccb56e..cb0478888 100644
--- a/examples/onchain-signer/contracts/Gasless.sol
+++ b/examples/onchain-signer/contracts/Gasless.sol
@@ -2,7 +2,6 @@
 pragma solidity ^0.8.19;
 
 import {EIP155Signer} from "@oasisprotocol/sapphire-contracts/contracts/EIP155Signer.sol";
-import {EthereumUtils} from "@oasisprotocol/sapphire-contracts/contracts/EthereumUtils.sol";
 
 struct EthereumKeypair {
     address addr;
@@ -12,14 +11,13 @@ struct EthereumKeypair {
 
 // Proxy for gasless transaction.
 contract Gasless {
-    error KeyPairNotSet();
-
     EthereumKeypair private kp;
 
-    constructor () payable {
-        (kp.addr, kp.secret) = EthereumUtils.generateKeypair();
-
-        payable(kp.addr).transfer(msg.value);
+    constructor (EthereumKeypair memory keypair) payable {
+        kp = keypair;
+        if( msg.value > 0 ) {
+            payable(kp.addr).transfer(msg.value);
+        }
     }
 
     function makeProxyTx(address innercallAddr, bytes memory innercall)
@@ -28,9 +26,6 @@ contract Gasless {
         returns (bytes memory output)
     {
         bytes memory data = abi.encode(innercallAddr, innercall);
-        if (kp.secret == 0) {
-            revert KeyPairNotSet();
-        }
 
         // Call will invoke proxy().
         return
diff --git a/examples/onchain-signer/test/CommentBox.ts b/examples/onchain-signer/test/CommentBox.ts
index 7b7c92b39..f932cc19f 100644
--- a/examples/onchain-signer/test/CommentBox.ts
+++ b/examples/onchain-signer/test/CommentBox.ts
@@ -1,19 +1,37 @@
 import { expect } from 'chai';
-import { ethers } from 'hardhat';
+import { ethers, config } from 'hardhat';
 import { CommentBox, Gasless } from '../typechain-types';
+import { EthereumKeypairStruct } from "../typechain-types/contracts/Gasless"
 import { parseEther } from 'ethers/lib/utils';
+import { HDAccountsUserConfig } from 'hardhat/types';
 
 describe('CommentBox', function () {
   let commentBox: CommentBox;
   let gasless: Gasless;
 
   before(async () => {
+    // Derive the private key of the 1st (counting from 0) builtin hardhat test account.
+    const accounts = config.networks.hardhat
+      .accounts as unknown as HDAccountsUserConfig;
+    const wallet1 = ethers.Wallet.fromMnemonic(
+      accounts.mnemonic,
+      accounts.path + `/1`,
+    );
+
+    // Use it as the relayer private key.
+    // NOTE can be done by the contract with EthereumUtils.generateKeypair()
+    const keypair : EthereumKeypairStruct = {
+      addr: wallet1.address,
+      secret: wallet1.privateKey,
+      nonce: ethers.provider.getTransactionCount(wallet1.address),
+    };
+
     const CommentBoxFactory = await ethers.getContractFactory('CommentBox');
     commentBox = await CommentBoxFactory.deploy();
     await commentBox.deployed();
 
     const GaslessFactory = await ethers.getContractFactory('Gasless');
-    gasless = await GaslessFactory.deploy({value: parseEther('0.1')});
+    gasless = await GaslessFactory.deploy(keypair, {value: parseEther('0.1')});
     await gasless.deployed();
   });