Heroes: Testing initial heroes state

heroes.container.spec.ts

describe('emits all heroes', () => {
  it('all heroes are emitted after subscribing', () => {
    expect(observer).toHaveBeenCalledWith(femaleMarvelHeroes);
  });

  it(`delegates to ${HeroService.name}`, () => {
    expect(heroServiceStub.getHeroes).toHaveBeenCalledTimes(1);
  });
});