CODEWITHSUNDEEP
angularjsjasmine
Jonathan Benevides
Jonathan Benevides

Reputation: 89

How to test an EventEmitter from service

I am new in Angular/Jasmine and need help to test a little peace of code.

My ts file createcustomer.ts My method shoots a boolean event that is listened in another component. I need test if the event below was emitted

export class CreateCustomerComponent {
  constructor(public breadCrumbService: BreadCrumbService) { }
  emit() {
    this.breadCrumbService.createCustomer$.emit(false)
  }
}

createcustomer.spec.ts I wanna test my method above

emit() {
  this.breadCrumbService.createCustomer$.emit(false)
}

My test pass and I know how to test a simple emit in component, but an emit of a service I do know yet.

describe('CreateCustomerComponent ', () => {
  let component: CreateCustomerComponent ;
  let fixture: ComponentFixture<CreateCustomerComponent >;

  beforeEach(async(() => {
    TestBed.configureTestingModule({
      imports: [ ],
      declarations: [
        createCustomerComponent
      ],
      schemas: [
        NO_ERRORS_SCHEMA
      ],
      providers: [
        { provide: BreadCrumbService }
      ]
    })
    .compileComponents();
  }));

  beforeEach(() => {
    fixture = TestBed.createComponent(CreateBotComponent);
    component = fixture.componentInstance;
  });

  it('should create the component CreateCustomerComponent ', () => {
    expect(component).toBeTruthy();
  });

I expect createCustomer$ haveBeenCalledWith(false)

Upvotes: 1

Views: 3244

Answers (1)

Xesenix
Xesenix

Reputation: 2548

describe('CreateCustomerComponent ', () => {
  let component: CreateCustomerComponent ;
  let fixture: ComponentFixture<CreateCustomerComponent >;

  beforeEach(async(() => {
    TestBed.configureTestingModule({
      ...
      providers: [
        {
          provide: BreadCrumbService,
          // use can describe structure of mocked object with useValue or use declare mock class and bind it with useClass
          useValue: { createCustomer$: { emit: jasmine.createSpy('emit') } }
        }
      ]
    })
    .compileComponents();
  }));

  ...
  // what method do we test
  describe('.emit()', () => {
    // expected  behaviors
    it('should emit false via createCustomer$ from breadCrumbService', inject([BreadCrumbService], (service: BreadCrumbService) => {
      component.emit();// or you can play around and try to trigger it via template interactions
      expect(service.createCustomer$.emit).toHaveBeenCalledWith(false);
    }));
  });

Upvotes: 2

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