Typescript (Angular): unit test subscription

Question

I have a simple function that does this

ngOnInit() { if (this.session.getToken()) { this.isUserLogged = true; } this.loadingObserver = this.session.loadingObservable.subscribe(loading => this.isLoading = loading); } 

and my test is as follows

 it('Testing ngOnInit() ...', async(() => { let spy = spyOn(services.session, 'getToken').and.returnValue('token'); services.session.loadingObservable.subscribe(any => expect(component.isLoading).toEqual(false)); component.ngOnInit(); expect(component.isUserLogged).toEqual(true); expect(spy).toHaveBeenCalled(); })); 

But in the scope of my application code, the subscription does not apply. In fact, waiting for fake also works.

Do you have any ideas on testing your subscription?