单元测试是软件开发过程中重要的测试防线,在确保应用程序的质量和稳定性方面扮演着关键角色。JavaScript Worker 的运行环境不同于浏览器和 Node.js,因此需要特殊的测试方法来验证其功能。本文将介绍使用 Jest 进行 JavaScript Worker 的单元测试。
使用提前准备好的三个工具函数,可以协助开发者使用 Jest 进行 Worker 单元测试:
setupWorkerTest
:这个函数用于设置Worker测试环境。它会创建一些模拟对象和函数,以便在单元测试中模拟 Worker 的行为;clearWorkerTest
:这个函数用于清除 Worker 测试环境,保证测试环境干净;triggerFetchEvent
:这个函数用于触发fetch
事件,模拟一个Request
对象,然后测试 Worker 是如何处理这个请求的;
以下面的 Worker 代码为例,简单介绍如何编写 Worker 测试用例:
addEventListener("fetch", (event) => {
console.log(event.request.url);
if (event.request.url.includes("test")) {
event.respondWith(new Response("Hello Test!"));
return;
}
event.respondWith(new Response("Hello Worker!"));
});
编写 worker.test.js
对代码进行测试:
// worker.test.js
const path = require('path');
const { setupWorkerTest, clearWorkerTest, triggerFetchEvent } = require('../src');
describe('worker test', () => {
beforeAll(() => {
setupWorkerTest(path.resolve(__dirname, './worker.js'));
});
afterAll(() => {
clearWorkerTest();
});
it('respond with "Hello Worker!"', async () => {
const response = await triggerFetchEvent('http://localhost:8000/');
expect(console.log).toHaveBeenCalledWith('http://localhost:8000/');
expect(response).toBeInstanceOf(Response);
expect(response.status).toBe(200);
const text = await response.text();
expect(text).toBe('Hello Worker!');
});
it('respond with "Hello Test!"', async () => {
const response = await triggerFetchEvent('http://localhost:8000/test');
expect(console.log).toHaveBeenCalledWith('http://localhost:8000/test');
expect(response).toBeInstanceOf(Response);
expect(response.status).toBe(200);
const text = await response.text();
expect(text).toBe('Hello Test!');
});
});
使用 Jest 运行测试:
npm run jest
> [email protected] jest
> jest --coverage
PASS test/worker.test.js
worker test
✓ respond with "Hello Worker!" (2 ms)
✓ respond with "Hello Test!" (1 ms)
-----------|---------|----------|---------|---------|-------------------
File | % Stmts | % Branch | % Funcs | % Lines | Uncovered Line #s
-----------|---------|----------|---------|---------|-------------------
All files | 100 | 100 | 100 | 100 |
worker.js | 100 | 100 | 100 | 100 |
-----------|---------|----------|---------|---------|-------------------
Test Suites: 1 passed, 1 total
Tests: 2 passed, 2 total
Snapshots: 0 total
Time: 0.288 s, estimated 1 s
Ran all test suites.