Question

我正在按照此示例进行服务的单元测试（获取来自Spring应用程序后端的请求）https://angular.io/guide/testing#testing-http-services

服务类别：

@Injectable()
export class TarifService {

  constructor(private messageService: MessageService, private http: HttpClient) { }

  public getTarifs(): Observable<Tarif[]> {
    return this.http.get<Tarif[]>(tarifffsURL).pipe(
      tap(() => {}),
      catchError(this.handleError('getTarifs', []))
    );
  }
}

单元测试

describe('TarifService', () => {

  let tarifService: TarifService;
  let httpClientSpy: { get: jasmine.Spy };
  let expectedTarifs;

  beforeEach(() => {
    TestBed.configureTestingModule({
      imports: [ToastrModule.forRoot(), HttpClientModule, HttpClientTestingModule],
      providers: [TarifService, HttpClient, MessageService]
    });

    httpClientSpy = jasmine.createSpyObj('HttpClient', ['get']);
    tarifService = new TarifService(<any> MessageService,<any> httpClientSpy);

  });


  it('should be created', inject([TarifService], (service: TarifService) => {
    expect(service).toBeTruthy();
  }));


  it('should return expected tarif (HttpClient called once)', () => {
    const expectedTarifs: Tarif[] =
      [{ id: 1, name: 'Tarif1', value: '20' }, { id: 2, name: 'Tarif2', value:'30' }];

    httpClientSpy.get.and.returnValue(expectedTarifs);

    tarifService.getTarifs().subscribe(
      tarifs => expect(tarifs).toEqual(expectedTarifs, 'expected tarifs'),
      fail
    );
    expect(httpClientSpy.get.calls.count()).toBe(1, 'one call');
  });
});

运行测试时，我一直遇到此错误

TarifService should return expected tarif (HttpClient called once)
TypeError: this.http.get(...).pipe is not a function

这可能是什么原因？

Answer 1

问题在于，调用spy时，它将返回Array，而Array没有pipe函数。您需要从Observable返回spy，就像这样

const expectedTarifs: Tarif[] =
  [{ id: 1, name: 'Tarif1', value: '20' }, { id: 2, name: 'Tarif2', value:'30' }];

httpClientSpy.get.and.returnValue(Observable.of(expectedTarifs));

查看returnValue是Observable.of(expectedTarifs)的方式。 Observable.of创建一个Observable，它会发出一个您指定为自变量的值，一个接一个地发出，然后发出一个完整的通知。 See the docs

希望有帮助

Answer 2

为了使我的工作，我必须这样做：

import { from } from 'rxjs';

然后：

return from([expectedTarifs]);

Angular单元测试TypeError：this.http.get（...）。pipe不是函数

2 个答案: