如何对返回 Promise 的异步方法进行单元测试

Question

我正在尝试使用在我的 Angular 应用程序中返回承诺的方法来测试服务。

但我不断收到错误Async 功能未在 5000 毫秒内完成

我的服务看起来像这样

  public async startApp(data) {
    if (data === { }) this.logout()
    const url = environment.API_HOST + environment.ENDPOINT + '/start-app'
    return this.sendRequest<responseType>(url, data).toPromise()
  }

  private sendRequest<T>(url: string, data: any): Observable<T> {
    return this.http.post<T>(
      url, data, { headers: this.headers(), observe: 'response', responseType: 'json' }
    ).pipe(
      map((resp: any) => {
        return resp.body
      }))
  }

我的规范文件如下所示：

describe('MyService', () => {
      let service: MyService

      TestBed.configureTestingModule({ providers: [ MyService ] })

      service = TestBed.get(MyService)
    })

    it('should start app', async (done: DoneFn) => {
       const res = await service.startApp({ data: 'someData' })
       done()
    })

我究竟做错了什么？

如果可能的话，我会避免监视sendRequest因为它是一个私有方法，否则我无法对其进行测试

Answer 1

看到您的应用程序正在执行 http，您需要将其注入到您的配置中。

import { HttpClientTestingModule,
         HttpTestingController } from '@angular/common/http/testing';
......
describe('MyService', () => {
  let httpTestingController: HttpTestingController;
  let service: MyService;

  beforeEach(() => {
    TestBed.configureTestingModule({
      providers: [MyService],
      imports: [HttpClientTestingModule],
    });
    // get a handle on the HTTPController
    httpTestingController = TestBed.get(HttpTestingController);
    service = TestBed.get(CoursesService);
  });

  afterEach(() => {
    // verify no pending requests after each test
    httpTestingController.verify();
  });

  it('should start app and send a post request', async (done: DoneFn) => {
       service.startApp({ data: 'someData' }).then(response => {
         expect(response.body).toBe('helloWorld');
         // put the rest of your assertions here.
         done();
       });
       const mockResponse = { body: 'helloWorld' }; // mock the response to what you would like
       const req = httpTestingController.expectOne(... put here whatever the url, data is/ will resolve to);
       expect(req.request.method).toEqual('POST');
       // for the next HTTP request for that URL, give this as the response
       req.flush(mockResponse);
  });
});

startApp调用一个函数，该函数以可观察的方式进行 API 调用，但您将其转换为承诺，但我很确定我为您提供的内容应该很好。

适合您的链接： https : //medium.com/better-programming/testing-http-requests-in-angular-with-httpclienttestingmodule-3880ceac74cf