import {TestBed, waitForAsync} from '@angular/core/testing'; import {SongService} from './song.service'; import {SongDataService} from './song-data.service'; import {of} from 'rxjs'; describe('SongService', () => { const songs = [{title: 'title1'}]; const mockSongDataService = { list: () => of(songs), }; beforeEach( () => void TestBed.configureTestingModule({ providers: [{provide: SongDataService, useValue: mockSongDataService}], }) ); it('should be created', () => { const service: SongService = TestBed.inject(SongService); void expect(service).toBeTruthy(); }); it( 'should list songs', waitForAsync(() => { const service: SongService = TestBed.inject(SongService); service.list$().subscribe(s => { void expect(s[0].title).toEqual('title1'); }); }) ); });