单元测试角度服务，无法通过beforeeach注入依赖项

Question

我正在尝试对具有@viewChild组件和少量其他服务的组件进行单元测试。

以下是我的spec.ts文件。

  beforeEach(() => {
    TestBed.configureTestingModule({
      declarations: [ UpStoryComponent,ExperienceListComponent, MdToHtmlPipe, SafeUrlPipe, FormatUrlPipe, CurrencyFormatPipe, NoCommaPipe, MoneyPipe, SafeHtmlPipe],
      imports: [ FormsModule, HttpClientTestingModule, RouterTestingModule],
      providers: [{ provide: ActivatedRoute, useValue: {'params': Observable.from([{ 'id': 1}])}, ContentfulService, MatchingFlowService, FormDataService, LocalStorageService, ScrollService, Title, UpnorwayLoaderService, MoneyService, DayCalculatorService],
      schemas: [NO_ERRORS_SCHEMA]    
    }).compileComponents();
  });


  beforeEach(() => {
    fixture = TestBed.createComponent(UpStoryComponent);
    component = fixture.componentInstance;     
    component.experienceListComponent = TestBed.createComponent(ExperienceListComponent).componentInstance;
    fixture.detectChanges();
  });

  beforeEach(() => {
    contentfulService = TestBed.get(ContentfulService);
    spyOn(contentfulService, 'getEntryBySlug').and.callFake(function (args) {
      return of(blogPost);
    });
    fixture.detectChanges();
  });


  it('should create', () => { 
    expect(component).toBeTruthy();
  }); 

最后一条beforeeach语句被执行，但未按预期注入服务。如果我将最后一个beforeeach语句放置为第二个beforeeach语句，那么当前的第二个beforeeach语句将无法按预期执行。

ExperienceListComponent和ContentfulService之间没有依赖关系。但是，当通过beforeach语句注入这两个服务时，只有第一个注入有效，而另一个则无效。

这可能是什么原因？感谢您是否可以为此提供解决方案。