創建hardhat工程, 用于Solidity測驗

? ? hardhat是一個專門用來進行Solidity智能合約開發、部署和測驗的軟體工具集，它既可以像ganache一樣，在本地自動化部署一個以太坊網路，又可以像truffle一樣，快捷的部署、測驗和除錯Solidity智能合約，即 hardhat = ganache + truffle，
? ? 下面，介紹hardhat的工程創建流程，這里以onehat工程為例，

1、創建檔案夾并初始化

mkdir onehat
npm init -y

2、修改package.json

? ? 修改package.json，主要是添加devDependencies欄位：
? ? //package.json

{
  "name": "onehat",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "keywords": [],
  "author": "",
  "license": "ISC",
  "devDependencies": {
    "@nomiclabs/hardhat-ethers": "^2.0.2",
    "@nomiclabs/hardhat-waffle": "^2.0.1",
    "chai": "^4.3.4",
    "ethereum-waffle": "^3.4.0",
    "ethers": "^5.4.7",
    "hardhat": "^2.6.5"
  }
}

? ? 安裝依賴包

npm install

3、創建hardhat組態檔

? ? 在onehat目錄下， 新建一個hardhat.config.js檔案

touch hardhat.config.js

? ? hardhat.config.js的內容如下：
? ? // onehat/harhat.config.js

/**
 * @type import('hardhat/config').HardhatUserConfig
 */

require("@nomiclabs/hardhat-waffle");

module.exports = {
  solidity: "0.6.12",
};

4、撰寫.sol智能合約

? ? 新建一個智能合約檔案onehat/contracts/Token.sol

mkdir contracts
cd contracts
touch Token.sol

? ? Token.sol的內容如下：
? ? // onehat/contracts/Token.sol

//SPDX-License-Identifier: MIT
pragma solidity ^0.6.0;


// This is the main building block for smart contracts.
contract Token {
    // Some string type variables to identify the token.
    // The `public` modifier makes a variable readable from outside the contract.
    string public name = "My Hardhat Token";
    string public symbol = "MBT";

    // 固定發行量，保存在一個無符號整型里
    uint256 public totalSupply = 1000000;

    // An address type variable is used to store ethereum accounts.
    address public owner;

    // A mapping is a key/value map. Here we store each account balance.
    mapping(address => uint256) balances;

    /**
     * 合約建構式
     *
     * The `constructor` is executed only once when the contract is created.
     */
    constructor() public {
        // The totalSupply is assigned to transaction sender, which is the account
        // that is deploying the contract.
        balances[msg.sender] = totalSupply;
        owner = msg.sender;
    }

    /**
     * 代幣轉賬.
     *
     * The `external` modifier makes a function *only* callable from outside
     * the contract.
     */
    function transfer(address to, uint256 amount) external {
        // Check if the transaction sender has enough tokens.
        // If `require`'s first argument evaluates to `false` then the
        // transaction will revert.
        require(balances[msg.sender] >= amount, "Not enough tokens");

        // Transfer the amount.
        balances[msg.sender] -= amount;
        balances[to] += amount;
    }

    /**
     * 回傳賬號的代幣余額，只讀函式，
     *
     * The `view` modifier indicates that it doesn't modify the contract's
     * state, which allows us to call it without executing a transaction.
     */
    function balanceOf(address account) external view returns (uint256) {
        return balances[account];
    }
}

5、編譯智能合約

## 進入工程檔案夾
cd onehat

## 編譯智能合約
npx hardhat compile

6、工程的目錄結構

7、測驗智能合約

7.1 新建.js測驗腳本

? ? 新建一個測驗腳本: onehat/test/token.js

cd onehat
mkdir test
cd test
touch token.js

? ? token.js的內容如下：
? ? //token.js

// We import Chai to use its asserting functions here.
const { expect } = require("chai");

// `describe` is a Mocha function that allows you to organize your tests. It's
// not actually needed, but having your tests organized makes debugging them
// easier. All Mocha functions are available in the global scope.

// `describe` receives the name of a section of your test suite, and a callback.
// The callback must define the tests of that section. This callback can't be
// an async function.
describe("Token contract", function () {
  // Mocha has four functions that let you hook into the the test runner's
  // lifecyle. These are: `before`, `beforeEach`, `after`, `afterEach`.

  // They're very useful to setup the environment for tests, and to clean it
  // up after they run.

  // A common pattern is to declare some variables, and assign them in the
  // `before` and `beforeEach` callbacks.

  let Token;
  let hardhatToken;
  let owner;
  let addr1;
  let addr2;
  let addrs;

  // `beforeEach` will run before each test, re-deploying the contract every
  // time. It receives a callback, which can be async.
  beforeEach(async function () {
    // Get the ContractFactory and Signers here.
    Token = await ethers.getContractFactory("Token");
    [owner, addr1, addr2, ...addrs] = await ethers.getSigners();

    // To deploy our contract, we just have to call Token.deploy() and await
    // for it to be deployed(), which happens onces its transaction has been
    // mined.
    hardhatToken = await Token.deploy();
  });

  // You can nest describe calls to create subsections.
  describe("Deployment", function () {
    // `it` is another Mocha function. This is the one you use to define your
    // tests. It receives the test name, and a callback function.

    // If the callback function is async, Mocha will `await` it.
    it("Should set the right owner", async function () {
      // Expect receives a value, and wraps it in an Assertion object. These
      // objects have a lot of utility methods to assert values.

      // This test expects the owner variable stored in the contract to be equal
      // to our Signer's owner.
      expect(await hardhatToken.owner()).to.equal(owner.address);
    });

    it("Should assign the total supply of tokens to the owner", async function () {
      const ownerBalance = await hardhatToken.balanceOf(owner.address);
      expect(await hardhatToken.totalSupply()).to.equal(ownerBalance);
    });
  });

  describe("Transactions", function () {
    it("Should transfer tokens between accounts", async function () {
      // Transfer 50 tokens from owner to addr1
      await hardhatToken.transfer(addr1.address, 50);
      const addr1Balance = await hardhatToken.balanceOf(addr1.address);
      expect(addr1Balance).to.equal(50);

      // Transfer 50 tokens from addr1 to addr2
      // We use .connect(signer) to send a transaction from another account
      await hardhatToken.connect(addr1).transfer(addr2.address, 50);
      const addr2Balance = await hardhatToken.balanceOf(addr2.address);
      expect(addr2Balance).to.equal(50);
    });

    it("Should fail if sender doesn’t have enough tokens", async function () {
      const initialOwnerBalance = await hardhatToken.balanceOf(owner.address);

      // Try to send 1 token from addr1 (0 tokens) to owner (1000 tokens).
      // `require` will evaluate false and revert the transaction.
      await expect(
        hardhatToken.connect(addr1).transfer(owner.address, 1)
      ).to.be.revertedWith("Not enough tokens");

      // Owner balance shouldn't have changed.
      expect(await hardhatToken.balanceOf(owner.address)).to.equal(
        initialOwnerBalance
      );
    });

    it("Should update balances after transfers", async function () {
      const initialOwnerBalance = await hardhatToken.balanceOf(owner.address);

      // Transfer 100 tokens from owner to addr1.
      await hardhatToken.transfer(addr1.address, 100);

      // Transfer another 50 tokens from owner to addr2.
      await hardhatToken.transfer(addr2.address, 50);

      // Check balances.
      const finalOwnerBalance = await hardhatToken.balanceOf(owner.address);
      expect(finalOwnerBalance).to.equal(initialOwnerBalance - 150);

      const addr1Balance = await hardhatToken.balanceOf(addr1.address);
      expect(addr1Balance).to.equal(100);

      const addr2Balance = await hardhatToken.balanceOf(addr2.address);
      expect(addr2Balance).to.equal(50);
    });
  });
});

7.2 運行測驗腳本

npx hardhat test test/token.js

? ? 效果如下：

? ? 如圖(2)所示，5個單元測驗，都測驗成功，

參考文獻

hardhat使用手冊