Node.js：Jest测试框架

Jest 是一个令人愉快的 JavaScript 测试框架，专注于 简洁明快。

• 官网 https://jestjs.io/
• 中文文档 https://jestjs.io/zh-Hans/
• 国内镜像：https://www.jestjs.cn/
• github: https://github.com/facebook/jest
• npmjs https://www.npmjs.com/package/jest

VS Code插件：Jest

// 如果不想自动运行，可以设置关闭
"jest.autoRun": "off"

基本环境

安装依赖

npm install -D jest babel-jest babel-core babel-preset-env regenerator-runtime

备注：安装babel 为了让jest 支持ES6语法 import/export

package.json

{
  "type": "module",
  "scripts": {
    "test": "jest --verbose"
  },
  "devDependencies": {
    "babel-core": "^6.26.3",
    "babel-jest": "^28.1.3",
    "babel-preset-env": "^1.7.0",
    "jest": "^28.1.3",
    "regenerator-runtime": "^0.13.9"
  }
}

babel 配置文件 .babelrc

{
  "presets": ["env"]
}

测试示例

src/functions.js

export default {
  sum(a, b) {
    return a + b
  },
}

tests/functions.test.js

import functions from '../src/functions'

test('sum(2 + 2) 等于 4', () => {
  expect(functions.sum(2, 2)).toBe(4)
})

运行测试

$ npx jest
 PASS  tests/functions.test.js
  ✓ sum(2 + 2) 等于 4 (1 ms)

Test Suites: 1 passed, 1 total
Tests:       1 passed, 1 total
Snapshots:   0 total
Time:        1.141 s
Ran all test suites.

参考 使用Jest测试JavaScript (入门篇)