Angular Vitest 测试快速入门 Angular Vitest 测试快速入门 | Zhiwei Li

Angular Vitest 测试快速入门 | AI生成和翻译

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Question: 如何为 Angular 20+ 项目编写并运行简单的 npm test？

Answer:

在 Angular 20+ 中（实际上从 Angular ~v15–16 开始），默认的 test runner 是 Vitest（取代了之前的 Karma + Jasmine）。

以下是在现代 Angular 项目（2025–2026 风格）中设置和编写简单测试最常见且整洁的方法：

1. Angular 20+ 中最常见且推荐的方式 (Vitest + jsdom)

# 运行测试 (这是 "npm test" 实际执行的操作)
npm test

# Watch mode (建议在开发过程中使用)
npm run test:watch

典型的 package.json 脚本如下所示：

"scripts": {
  "test": "ng test",
  "test:watch": "ng test --watch"
}

2. 最简单的测试示例 (2025+ 风格)

src/app/app.component.spec.ts

import { TestBed } from '@angular/core/testing';
import { AppComponent } from './app.component';

describe('AppComponent', () => {
  beforeEach(async () => {
    await TestBed.configureTestingModule({
      imports: [AppComponent],
    }).compileComponents();
  });

  it('should create the app', () => {
    const fixture = TestBed.createComponent(AppComponent);
    const app = fixture.componentInstance;
    expect(app).toBeTruthy();
  });

  it('should render title', () => {
    const fixture = TestBed.createComponent(AppComponent);
    fixture.detectChanges();
    const compiled = fixture.nativeElement as HTMLElement;
    expect(compiled.querySelector('h1')?.textContent).toContain('Welcome');
  });

  it('should have welcome message in component', () => {
    const fixture = TestBed.createComponent(AppComponent);
    const app = fixture.componentInstance;
    expect(app.title).toContain('angular');
  });
});

3. 更简单的方式 – 测试带有 signal input 的组件 (Angular 17+ 风格)

src/app/counter/counter.component.ts

import { Component, input } from '@angular/core';

@Component({
  selector: 'app-counter',
  standalone: true,
  template: `
    <p>Count: {{ count() }}</p>
    <button (click)="increment()">+1</button>
  `
})
export class CounterComponent {
  count = input(0);

  increment() {
    // 通常你会在这里使用 output 或 model()
  }
}

counter.component.spec.ts

import { ComponentFixture, TestBed } from '@angular/core/testing';
import { CounterComponent } from './counter.component';

describe('CounterComponent', () => {
  let component: CounterComponent;
  let fixture: ComponentFixture<CounterComponent>;

  beforeEach(async () => {
    await TestBed.configureTestingModule({
      imports: [CounterComponent]
    }).compileComponents();

    fixture = TestBed.createComponent(CounterComponent);
    component = fixture.componentInstance;
    fixture.detectChanges();
  });

  it('should display initial count', () => {
    expect(fixture.nativeElement.querySelector('p').textContent)
      .toContain('Count: 0');
  });

  it('should display count = 7 when input is set', () => {
    fixture.componentRef.setInput('count', 7);
    fixture.detectChanges();

    expect(fixture.nativeElement.querySelector('p').textContent)
      .toContain('Count: 7');
  });
});

快速清单 – 现代 Angular 测试 (2025+)

需求 推荐方案 命令
默认 Angular 18–20+ 配置 Vitest + jsdom ng test
运行一次 (CI) Headless mode npm test
开发 + watch 交互式 watch mode npm run test:watch
仅测试一个文件 Focus file ng test --include=**/*counter*
跳过组件样式测试 --include=**/*.spec.ts 更快的 CI
使用 Jest 代替？ 可行但不再是默认选项 需要手动配置

总结 – 最简单的开始方式

  1. 直接运行：

    npm test

  2. 或使用 watch mode（强烈推荐）：

    npm run test:watch

  3. 按照上面的示例编写测试 → 它们在 Angular 17/18/19/20+ 中均可正常工作

祝测试愉快！

References:

  • None needed for this Angular core knowledge question
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