angular - 使用@testing-library/angular 注入(inject)模拟服务

Question

我正在尝试使用 Kent C Dodds 的 @testing-library/angular 测试 Angular 组件。我的组件依赖于 Angular 服务。我在 api 文档中看不到有关如何注入(inject)模拟服务以为我的单元测试提供模拟数据的信息。

    export class ItemCounterComponent implements OnInit {
  public availableTodoCount: number;

  constructor(private todoProviderService: TodoProviderService) {
    this.todoProviderService.getTodos().subscribe(todos => {
      this.availableTodoCount = todos.filter(todo => !todo.completed).length;
    });
  }

  ngOnInit() {
  }

}

    describe('ItemCounterComponent', () => {

  it('shows the count correctly', async () => {
    const { getByText } = await render(ItemCounterComponent, { componentProperties: { availableTodoCount: 5 } });

    expect (getByText('5 items left'));
  });
});
````````````

Answer 1

您可以使用providers 来提供服务(就像您可以使用 TestBed 一样)

const component = await render(AppComponent, {
    providers: [
      {
        provide: TodoProviderService,
        useValue: { getTodos: ... },
      },
    ],
  });

更多示例位于:https://github.com/testing-library/angular-testing-library/tree/master/src/app/examples