时间戳

首页 > 解决方案 > Angular 单元测试 TypeError：this.http.get(...).pipe 不是函数

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

问题描述

我正在按照这个示例对服务进行单元测试（获取来自 Spring 应用后端的请求）https://angular.io/guide/testing#testing-http-services

服务等级：

@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，我一直有这个错误

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？

标签： angularunit-testingtypescriptjasminerxjs

解决方案

问题是，当你spy被调用时，它返回一个Array，并且Array没有pipe函数。Observable你需要从你的返回一个spy，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));

看看returnValue情况如何Observable.of(expectedTarifs)。Observable.of创建一个Observable发出你指定为参数的一些值，一个接一个，然后发出一个完整的通知。查看文档

在最新版本中rxjs我们可以使用of操作符

import { of } from 'rxjs';

//... omitting some code here for brevity 

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

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

希望能帮助到你

推荐阅读