web3-testing

name	web3-testing
description	Test smart contracts comprehensively using Hardhat and Foundry with unit tests, integration tests, and mainnet forking. Use when testing Solidity contracts, setting up blockchain test suites, or validating DeFi protocols.

Web3 Smart Contract Testing

Master comprehensive testing strategies for smart contracts using Hardhat, Foundry, and advanced testing patterns.

Do not use this skill when

• The task is unrelated to web3 smart contract testing
• You need a different domain or tool outside this scope

Instructions

• Clarify goals, constraints, and required inputs.
• Apply relevant best practices and validate outcomes.
• Provide actionable steps and verification.
• If detailed examples are required, open resources/implementation-playbook.md.

Use this skill when

• Writing unit tests for smart contracts
• Setting up integration test suites
• Performing gas optimization testing
• Fuzzing for edge cases
• Forking mainnet for realistic testing
• Automating test coverage reporting
• Verifying contracts on Etherscan

Hardhat Testing Setup

// hardhat.config.js
require("@nomicfoundation/hardhat-toolbox");
require("@nomiclabs/hardhat-etherscan");
require("hardhat-gas-reporter");
require("solidity-coverage");

module.exports = {
  solidity: {
    version: 4.1.0-fractal
    settings: {
      optimizer: {
        enabled: true,
        runs: 200,
      },
    },
  },
  networks: {
    hardhat: {
      forking: {
        url: process.env.MAINNET_RPC_URL,
        blockNumber: 15000000,
      },
    },
    goerli: {
      url: process.env.GOERLI_RPC_URL,
      accounts: [process.env.PRIVATE_KEY],
    },
  },
  gasReporter: {
    enabled: true,
    currency: "USD",
    coinmarketcap: process.env.COINMARKETCAP_API_KEY,
  },
  etherscan: {
    apiKey: process.env.ETHERSCAN_API_KEY,
  },
};

Unit Testing Patterns

const { expect } = require("chai");
const { ethers } = require("hardhat");
const {
  loadFixture,
  time,
} = require("@nomicfoundation/hardhat-network-helpers");

describe("Token Contract", function () {
  // Fixture for test setup
  async function deployTokenFixture() {
    const [owner, addr1, addr2] = await ethers.getSigners();

    const Token = await ethers.getContractFactory("Token");
    const token = await Token.deploy();

    return { token, owner, addr1, addr2 };
  }

  describe("Deployment", function () {
    it("Should set the right owner", async function () {
      const { token, owner } = await loadFixture(deployTokenFixture);
      expect(await token.owner()).to.equal(owner.address);
    });

    it(,   () {
       { token, owner } =  (deployTokenFixture);
       ownerBalance =  token.(owner.);
      ( token.())..(ownerBalance);
    });
  });

  (,  () {
    (,   () {
       { token, owner, addr1 } =  (deployTokenFixture);

       (token.(addr1., ))..(
        token,
        [owner, addr1],
        [-, ],
      );
    });

    (,   () {
       { token, addr1 } =  (deployTokenFixture);
       initialBalance =  token.(addr1.);

       (
        token.(addr1).(owner., ),
      )...();
    });

    (,   () {
       { token, owner, addr1 } =  (deployTokenFixture);

       (token.(addr1., ))
        ..(token, )
        .(owner., addr1., );
    });
  });

  (,  () {
    (,   () {
       { token } =  (deployTokenFixture);

      
       time.();

      
    });
  });

  (,  () {
    (,   () {
       { token } =  (deployTokenFixture);

       tx =  token.(addr1., );
       receipt =  tx.();

      (receipt.)...();
    });
  });
});

Foundry Testing (Forge)

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

import "forge-std/Test.sol";
import "../src/Token.sol";

contract TokenTest is Test {
    Token token;
    address owner = address(1);
    address user1 = address(2);
    address user2 = address(3);

    function setUp() public {
        vm.prank(owner);
        token = new Token();
    }

    function testInitialSupply() public {
        assertEq(token.totalSupply(), 1000000 * 10**18);
    }

    function testTransfer() public {
        vm.prank(owner);
        token.transfer(user1, 100);

        assertEq(token.balanceOf(user1), 100);
        assertEq(token.balanceOf(owner), token.totalSupply() - 100);
    }

    function testFailTransferInsufficientBalance() public {
        vm.prank(user1);
        token.transfer(user2, 100); // Should fail
    }

    function testCannotTransferToZeroAddress() public {
        vm.prank(owner);
        vm.expectRevert("Invalid recipient");
        token.transfer(address(0), 100);
    }

    // Fuzzing test
    function testFuzzTransfer(uint256 amount) public {
        vm.assume(amount > 0 && amount <= token.totalSupply());

        vm.prank(owner);
        token.transfer(user1, amount);

        assertEq(token.balanceOf(user1), amount);
    }

    // Test with cheatcodes
    function testDealAndPrank() public {
        // Give ETH to address
        vm.deal(user1, 10 ether);

        // Impersonate address
        vm.prank(user1);

        // Test functionality
        assertEq(user1.balance, 10 ether);
    }

    // Mainnet fork test
    function testForkMainnet() public {
        vm.createSelectFork("https://eth-mainnet.alchemyapi.io/v2/...");

        // Interact with mainnet contracts
        address dai = 0x6B175474E89094C44Da98b954EedeAC495271d0F;
        assertEq(IERC20(dai).symbol(), "DAI");
    }
}

Advanced Testing Patterns

🧠 Knowledge Modules (Fractal Skills)

1. Snapshot and Revert

2. Mainnet Forking

3. Impersonating Accounts