Hardhat is a powerful development environment for Ethereum that facilitates the creation, testing, and deployment of smart contracts. In a multi-signature wallet project, Hardhat plays a crucial role in managing the development lifecycle, including writing, testing, and deploying the multi-signature wallet smart contract. This guide will explain the role of Hardhat in such a project and provide sample code to demonstrate its usage.

What is a Multi-Signature Wallet?

A multi-signature wallet (or multi-sig wallet) requires multiple signatures (or approvals) to execute transactions. This enhances security by ensuring that no single individual has control over the wallet's funds. Multi-sig wallets are commonly used by organizations and DAOs (Decentralized Autonomous Organizations) to manage funds collectively.

Setting Up Your Hardhat Project

To start, you need to set up a Hardhat project. If you haven't done this yet, follow these steps:

mkdir multi-sig-wallet
cd multi-sig-wallet
npm init --yes
npm install --save-dev hardhat
npx hardhat

When prompted, select "Create a basic sample project" and follow the instructions to set up the project.

Creating the Multi-Signature Wallet Contract

Create a new file in the contracts directory named MultiSigWallet.sol:

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

contract MultiSigWallet {
    event Deposit(address indexed sender, uint amount);
    event Submit(uint indexed txIndex, address indexed owner, address indexed to, uint amount, bytes data);
    event Confirm(uint indexed txIndex, address indexed owner);
    event Revoke(uint indexed txIndex, address indexed owner);
    event Execute(uint indexed txIndex);

    address[] public owners;
    mapping(address => bool) public isOwner;

    struct Transaction {
        address to;
        uint amount;
        bytes data;
        bool executed;
        uint confirmations;
    }

    Transaction[] public transactions;
    mapping(uint => mapping(address => bool)) public isConfirmed;

    modifier onlyOwner() {
        require(isOwner[msg.sender], "Not an owner");
        _;
    }

    constructor(address[] memory _owners) {
        require(_owners.length > 0, "No owners");
        for (uint i = 0; i < _owners.length; i++) {
            require(!isOwner[_owners[i]], "Owner is not unique");
            isOwner[_owners[i]] = true;
            owners.push(_owners[i]);
        }
    }

    receive() external payable {
        emit Deposit(msg.sender, msg.value);
    }

    function submitTransaction(address _to, uint _amount, bytes memory _data) public onlyOwner {
        uint txIndex = transactions.length;
        transactions.push(Transaction({
            to: _to,
            amount: _amount,
            data: _data,
            executed: false,
            confirmations: 0
        }));
        emit Submit(txIndex, msg.sender, _to, _amount, _data);
    }

    function confirmTransaction(uint _txIndex) public onlyOwner {
        require(!isConfirmed[_txIndex][msg.sender], "Transaction already confirmed");
        isConfirmed[_txIndex][msg.sender] = true;
        transactions[_txIndex].confirmations += 1;
        emit Confirm(_txIndex, msg.sender);
    }

    function executeTransaction(uint _txIndex) public onlyOwner {
        Transaction storage transaction = transactions[_txIndex];
        require(transaction.confirmations > 1, "Not enough confirmations");
        require(!transaction.executed, "Transaction already executed");

        transaction.executed = true;
        (bool success, ) = transaction.to.call{value: transaction.amount}(transaction.data);
        require(success, "Transaction failed");
        emit Execute(_txIndex);
    }
}

Writing Tests for the Multi-Signature Wallet

Hardhat provides a testing framework to ensure that your smart contracts behave as expected. Create a new test file in the test directory named MultiSigWallet.test.js:

const { expect } = require("chai");

describe("MultiSigWallet", function () {
    let MultiSigWallet;
    let multiSigWallet;
    let owner1, owner2, owner3, addr1;

    beforeEach(async function () {
        [owner1, owner2, owner3, addr1] = await ethers.getSigners();
        const owners = [owner1.address, owner2.address, owner3.address];
        MultiSigWallet = await ethers.getContractFactory("MultiSigWallet");
 multiSigWallet = await MultiSigWallet.deploy(owners);
        await multiSigWallet.deployed();
    });

    it("should allow owners to submit transactions", async function () {
        await multiSigWallet.submitTransaction(addr1.address, ethers.utils.parseEther("1"), "0x");
        const transaction = await multiSigWallet.transactions(0);
        expect(transaction.to).to.equal(addr1.address);
        expect(transaction.amount).to.equal(ethers.utils.parseEther("1"));
    });

    it("should allow owners to confirm transactions", async function () {
        await multiSigWallet.submitTransaction(addr1.address, ethers.utils.parseEther("1"), "0x");
        await multiSigWallet.connect(owner1).confirmTransaction(0);
        const transaction = await multiSigWallet.transactions(0);
        expect(transaction.confirmations).to.equal(1);
    });

    it("should execute transaction with enough confirmations", async function () {
        await multiSigWallet.submitTransaction(addr1.address, ethers.utils.parseEther("1"), "0x");
        await multiSigWallet.connect(owner1).confirmTransaction(0);
        await multiSigWallet.connect(owner2).confirmTransaction(0);
        await multiSigWallet.executeTransaction(0);
        const balance = await ethers.provider.getBalance(addr1.address);
        expect(balance).to.equal(ethers.utils.parseEther("1"));
    });
});

Deploying the Multi-Signature Wallet

To deploy the multi-signature wallet, create a new deployment script in the scripts directory named deploy.js:

async function main() {
    const [owner1, owner2, owner3] = await ethers.getSigners();
    const owners = [owner1.address, owner2.address, owner3.address];
    const MultiSigWallet = await ethers.getContractFactory("MultiSigWallet");
    const multiSigWallet = await MultiSigWallet.deploy(owners);
    await multiSigWallet.deployed();
    console.log("MultiSigWallet deployed to:", multiSigWallet.address);
}

main()
    .then(() => process.exit(0))
    .catch((error) => {
        console.error(error);
        process.exit(1);
    });

Conclusion

In this guide, we explored the role of Hardhat in developing a multi-signature wallet project. We set up a Hardhat project, created a multi-signature wallet contract, wrote tests to ensure its functionality, and deployed the contract. Hardhat's powerful features streamline the development process, making it easier to build secure and reliable smart contracts.