angular - 如何在 Angular 中正确测试解析器服务的返回

Question

我发现在 Angular 中进行测试非常困难。为了处理尽可能少的样板文件，我尝试进行 jest/spectator 单元测试。

我想测试一个解析器。它应该从 catchError() 返回一个 Contact[] 或 EMPTY 类型的 Observable。结果只有两种。

以下是我到目前为止所拥有的，我知道它很粗糙。

resolve(route: ActivatedRouteSnapshot, state: RouterStateSnapshot): Observable<any> | 
   Observable<never> {
  return this.contactsService.getContacts()
    .pipe(
      catchError(err => EMPTY),
      tap(res => res)
    );

}

describe('ContactsResolverService', () => {
 let spectator: SpectatorService<ContactsResolverService>;

 const createService = createServiceFactory({
   service: ContactsResolverService,
   imports: [HttpClientModule]
 });

 beforeEach(() => {
   spectator = createService();
  });

 it('should call the resolve class method', fakeAsync ( () => {

   const contactsService = spectator.inject(ContactsService);
   contactsService.getContacts.andReturn( of( ['ContactObj', 'ContactObj', 'ContactObj']) );
   const mockSnapshot = createSpyObj<RouterStateSnapshot>('RouterStateSnapshot', 
   ['toString']);
   const mockR = createSpyObj<ActivatedRouteSnapshot>('ActivatedRouteSnapshot', 
   ['toString']);
   flushMicrotasks();
   const r = spectator.service.resolve(mockR, mockSnapshot)
   expect(r).toHaveBeenCalled();
  }));

});