Question

我试图在ionic4应用程序中对我的一些代码进行单元测试，调用一个端点并将响应映射到一个对象，它还会添加一个抽头，以便我可以从dataservice中将this.faults作为可观察的返回。

fetchFaults(): Observable<Fault[]>
{
return this.http.get<{data: Fault[]}>('https://server/api/faults')
  .pipe(tap((data) => this.faults = data.data) // cache
      , map((data) => data.data)); // return just Fault[] from data.data to the subscriber
}

我正在尝试使用

  describe('fetchFaults', () => {
    it('makes expected calls', () => {
      const httpClientStub: HttpClient = TestBed.get(HttpClient);
      spyOn(httpClientStub, 'get');
      service.fetchFaults();
      expect(httpClientStub.get).toHaveBeenCalled();
    });
  });

但是我收到错误消息无法读取未定义的属性“管道”，我是否需要从httpstub返回任何内容？

Answer 1

这是针对您的服务编写单元测试的正确方法。

import { TestBed, fakeAsync, tick, getTestBed } from '@angular/core/testing';
import { HttpClientTestingModule, HttpTestingController } from '@angular/common/http/testing';

import { FaultService, Fault } from './fault.service';

describe('Program Service Tests', () => {
    let injector: TestBed;
    let service: FaultService;
    let httpMock: HttpTestingController;

    beforeEach(() => {
        TestBed.configureTestingModule({
            imports: [HttpClientTestingModule],
            providers: [
                FaultService
            ]
        });

        injector = getTestBed();
        service = injector.get(FaultService);
        httpMock = injector.get(HttpTestingController);
    });

    afterEach(() => {
        httpMock.verify();
    });

    it('should get the faults', fakeAsync(() => {
        const results = {data: []};

        service.fetchFaults().subscribe(_ => expect(results.data).toBe(_));

        const req = httpMock.expectOne((request: HttpRequest<any>): boolean => {
            expect(request.url).toEqual('https://server/api/faults');
            expect(request.method).toBe('GET');
            return true;
        });
        req.flush(results);
        tick();
    }));
});

出现该错误的原因是您需要告诉间谍调用原始实现。您可以通过链接.and.callThrough()来实现。我上面包含的代码是一种更好，更彻底的测试实现。

测试httpclient调用时无法读取未定义的属性“ pipe”

1 个答案: