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.
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Master comprehensive testing strategies for smart contracts using Hardhat, Foundry, and advanced testing patterns.
// hardhat.config.js
require("@nomicfoundation/hardhat-toolbox");
require("@nomiclabs/hardhat-etherscan");
require("hardhat-gas-reporter");
require("solidity-coverage");
module.exports = {
solidity: {
version: "0.8.19",
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,
},
};
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("Should assign total supply to owner", async function () {
const { token, owner } = await loadFixture(deployTokenFixture);
const ownerBalance = await token.balanceOf(owner.address);
expect(await token.totalSupply()).to.equal(ownerBalance);
});
});
describe("Transactions", function () {
it("Should transfer tokens between accounts", async function () {
const { token, owner, addr1 } = await loadFixture(deployTokenFixture);
await expect(token.transfer(addr1.address, 50)).to.changeTokenBalances(
token,
[owner, addr1],
[-50, 50],
);
});
it("Should fail if sender doesn't have enough tokens", async function () {
const { token, addr1 } = await loadFixture(deployTokenFixture);
const initialBalance = await token.balanceOf(addr1.address);
await expect(
token.connect(addr1).transfer(owner.address, 1),
).to.be.revertedWith("Insufficient balance");
});
it("Should emit Transfer event", async function () {
const { token, owner, addr1 } = await loadFixture(deployTokenFixture);
await expect(token.transfer(addr1.address, 50))
.to.emit(token, "Transfer")
.withArgs(owner.address, addr1.address, 50);
});
});
describe("Time-based tests", function () {
it("Should handle time-locked operations", async function () {
const { token } = await loadFixture(deployTokenFixture);
// Increase time by 1 day
await time.increase(86400);
// Test time-dependent functionality
});
});
describe("Gas optimization", function () {
it("Should use gas efficiently", async function () {
const { token } = await loadFixture(deployTokenFixture);
const tx = await token.transfer(addr1.address, 100);
const receipt = await tx.wait();
expect(receipt.gasUsed).to.be.lessThan(50000);
});
});
});
// 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");
}
}
describe("Complex State Changes", function () {
let snapshotId;
beforeEach(async function () {
snapshotId = await network.provider.send("evm_snapshot");
});
afterEach(async function () {
await network.provider.send("evm_revert", [snapshotId]);
});
it("Test 1", async function () {
// Make state changes
});
it("Test 2", async function () {
// State reverted, clean slate
});
});
describe("Mainnet Fork Tests", function () {
let uniswapRouter, dai, usdc;
before(async function () {
await network.provider.request({
method: "hardhat_reset",
params: [
{
forking: {
jsonRpcUrl: process.env.MAINNET_RPC_URL,
blockNumber: 15000000,
},
},
],
});
// Connect to existing mainnet contracts
uniswapRouter = await ethers.getContractAt(
"IUniswapV2Router",
"0x7a250d5630B4cF539739dF2C5dAcb4c659F2488D",
);
dai = await ethers.getContractAt(
"IERC20",
"0x6B175474E89094C44Da98b954EedeAC495271d0F",
);
});
it("Should swap on Uniswap", async function () {
// Test with real Uniswap contracts
});
});
it("Should impersonate whale account", async function () {
const whaleAddress = "0x...";
await network.provider.request({
method: "hardhat_impersonateAccount",
params: [whaleAddress],
});
const whale = await ethers.getSigner(whaleAddress);
// Use whale's tokens
await dai
.connect(whale)
.transfer(addr1.address, ethers.utils.parseEther("1000"));
});
More detailed templates and worked examples live in references/details.md. Read that file for the full pattern library.
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Create or update AgentSkills. Use when designing, structuring, or packaging skills with scripts, references, and assets.
Create or update AgentSkills. Use when designing, structuring, or packaging skills with scripts, references, and assets.
Set up and use 1Password CLI (op). Use when installing the CLI, enabling desktop app integration, signing in (single or multi-account), or reading/injecting/running secrets via op.
CLI to manage emails via IMAP/SMTP. Use `himalaya` to list, read, write, reply, forward, search, and organize emails from the terminal. Supports multiple accounts and message composition with MML (MIME Meta Language).