Typescript 单元测试 | Jest | Mocha | Chai | Test | Supertest

使用 Mocha 和 Chai 进行单元测试

安装依赖
```
npm install mocha chai --save-dev
```
如果你需要运行测试,可以在 package.json 中添加测试脚本
```
{
  "scripts": {
    "test": "mocha"
  }
}
```

编写待测试的代码

// calculator.js
function add(a, b) {
  return a + b;
}

module.exports = { add };

编写单元测试

// test/calculator.test.js
const { expect } = require('chai');
const { add } = require('../calculator'); // 引入要测试的函数

describe('Calculator', function() {
  it('should add two numbers correctly', function() {
    const result = add(2, 3);
    expect(result).to.equal(5); // 断言结果应该为 5
  });

  it('should add negative numbers correctly', function() {
    const result = add(-2, -3);
    expect(result).to.equal(-5); // 断言结果应该为 -5
  });

  it('should add a positive and a negative number correctly', function() {
    const result = add(2, -3);
    expect(result).to.equal(-1); // 断言结果应该为 -1
  });
});

运行测试
```
npm test
```

输出测试用例

Calculator
    ✓ should add two numbers correctly
    ✓ should add negative numbers correctly
    ✓ should add a positive and a negative number correctly


  3 passing (10ms)

2. 使用 Jest 进行单元测试

Jest 是一个自带断言库、模拟功能和测试运行器的测试框架,因此不需要额外安装断言库.

安装 Jest
```
npm install --save-dev jest
```
如果你需要运行测试,可以在 package.json 中添加测试脚本
```
{
  "scripts": {
    "test": "jest"
  }
}
```

编写待测试的代码

// calculator.js
function add(a, b) {
  return a + b;
}

module.exports = { add };

编写单元测试

函数测试

// test/calculator.test.js
// calculator.test.js
const { add } = require('./calculator');

test('should add two numbers correctly', () => {
  expect(add(2, 3)).toBe(5);
});

test('should add negative numbers correctly', () => {
  expect(add(-2, -3)).toBe(-5);
});

test('should add a positive and a negative number correctly', () => {
  expect(add(2, -3)).toBe(-1);
});

API 测试, 安装npm install jest supertest

import request from 'supertest';
import app from './app';

describe('API Tests', () => {
  it('GET /api/hello should return "Hello World!"', async () => {
    const res = await request(app).get('/api/hello');
    expect(res.statusCode).toBe(200);
    expect(res.body).toEqual({ message: 'Hello World!' });
  });
});

运行测试
```
npm test
```

输出测试用例

PASS  ./calculator.test.js
    ✓ should add two numbers correctly (3 ms)
    ✓ should add negative numbers correctly (1 ms)
    ✓ should add a positive and a negative number correctly (1 ms)

PASS  ./app.test.js
    ✓ GET /api/hello should return "Hello World!" (40 ms)

  Test Suites: 2 passed, 2 total
  Tests:       4 passed, 4 total
  Snapshots:   0 total
  Time:        0.639 s, estimated 2 s