CODEWITHSUNDEEP
angularunit-testingjasmine
Kartheek Sarabu
Kartheek Sarabu

Reputation: 3926

unable to test subscribe in ngOnInit()

I am using Observable for event subscription but I am unable to test it

Here is my code

Service

export class EventService<T> {
    private eventSubject = new Subject<string>();
    eventSubject$ = this.eventSubject.asObservable();

    dispathEvent(name) {
       this.eventSubject.next(name);
    }
}

Component

export class UserComponent implements OnInit{
    getSub: Subscription;
    constructor(private service EventService, private otherService OtherServece)(){}
    ngOnInt(){
      this.getSub = this.service.eventSubject$.subscribe(name =>{
         this.otherService.performAction();
         this.otherService.setVar = name;
      })

    }
}

Spec File

     let mockEventService :any;
     mockEventService = {
  eventSubject: jasmine.createSpyObj('eventSubject', ['next']),
  eventSubject$: jasmine.createSpyObj('eventSubject$', ['subscribe']),
};
     //some code
     providers: [{ provide: EventService, useValue: mockEventService }]
     // some code
     fixture = TestBed.createComponent(UserComponent);
     component = new TeamOvertimeComponent(mockEventService ,mockOtherService);
     ....
      it('should test ngOnInt Service var status', () => {
        expect(mockEventService.eventSubject$['subscribe']).toHaveBeenCalled()
fixture.detectChanges();
//
component.ngOnInit();
      });

I am seeing issue as 

TypeError: this.service.eventSubject$.subscribe is not a function

I tried keeping them in before each but still issue exists

Upvotes: 1

Views: 898

Answers (1)

Poul Kruijt
Poul Kruijt

Reputation: 71961

You need to create a spy from the object that has the subscribe method, in this case the observable:

mockEventService = {
  eventSubject: jasmine.createSpyObj('eventSubject', ['next']),
  eventSubject$: jasmine.createSpyObj('eventSubject$', ['subscribe']),
};

The rest of the code you can keep the same, as far as I can see. And you can spy on it like this:

expect(mockOvertimeService.eventSubject$['subscribe']).toHaveBeenCalled()

To test the subscribe block you can do something like this (untested code):

mockEventService = {
  eventSubject$: { subscribe: jasmine.createSpy().and.callFake((cb) => cb('test')) }
};

otherService = {
  performAction: jasmine.createSpy()
};

fixture.detectChanges();

expect(mockEventService.eventSubject$['subscribe']).toHaveBeenCalled();
expect(otherService.performAction).toHaveBeenCalled();
expect(otherService.setVar).toBe('test');

Upvotes: 2

Related Questions