import { async , ComponentFixture , TestBed } from '@angular/core/testing' ; import { CounterComponent } from './counter.component' ; describe ( 'CounterComponent' , ( ) => { let component ; let fixture ; beforeEach ( async ( ( ) => { TestBed . configureTestingModule ( { declarations : [ CounterComponent ] } ) . compileComponents ( ) ; } ) ) ; beforeEach ( ( ) => { fixture = TestBed . createComponent ( CounterComponent ) ; component = fixture . componentInstance ; fixture . detectChanges ( ) ; } ) ; it ( 'should display a title' , async ( ( ) => { const titleText = fixture . nativeElement . querySelector ( 'h1' ) . textContent ; expect ( titleText ) . toEqual ( 'Counter' ) ; } ) ) ; it ( 'should start with count 0, then increments by 1 when clicked' , async ( ( ) => { const countElement = fixture . nativeElement . querySelector ( 'strong' ) ; expect ( countElement . textContent ) . toEqual ( '0' ) ; const incrementButton = fixture . nativeElement . querySelector ( 'button' ) ; incrementButton . click ( ) ; fixture . detectChanges ( ) ; expect ( countElement . textContent ) . toEqual ( '1' ) ; } ) ) ; } ) ;