CODEWITHSUNDEEP
angularjasminerxjs
Michael Martinez
Michael Martinez

Reputation: 191

Test that a method in an Angular component called subscribe

If I have the following delete method in a component

@Component({
  selector: 'app-heroes',
  templateUrl: './heroes.component.html',
  styleUrls: ['./heroes.component.css']
})
export class HeroesComponent {
  this.heroes = [];

  constructor(private heroService: HeroService) { }

  delete(hero: Hero): void {
    this.heroes = this.heroes.filter(h => h !== hero);
    this.heroService.deleteHero(hero).subscribe();
  }
}

How can I test in Jasmine that the delete hero method has called subscribe in a test.

Here is a test which ensures deleteHero was called with a specific argument, but I'm unsure how to check for a subscription.

// Interaction Test
it('should call deleteHero with the specificed argument', () => {
  // arrange
  mockHeroService.deleteHero.and.returnValue(of(true));
  component.heroes = HEROES;

  // act
  component.delete(HEROES[2]);

  // assert
  expect(mockHeroService.deleteHero).toHaveBeenCalledWith(HEROES[2]);
});

Upvotes: 1

Views: 919

Answers (1)

user4676340
user4676340

Reputation:

You're going to need two spies : 

it('should call deleteHero with the specificed argument', () => {
  const resMock = of(true);
  spyOn(resMock, 'subscribe'); // No need to .and since you do nothing after it
  mockHeroService.deleteHero.and.returnValue(resMock);
  component.heroes = HEROES;

  component.delete(HEROES[2]);

  expect(mockHeroService.deleteHero).toHaveBeenCalledWith(HEROES[2]);
  expect(resMock.subscribe).toHaveBeenCalledWith(); // check if no callback is given
});

Upvotes: 6

Related Questions