Test Broadcast Service

Hi I am trying to write angular code for a component with an observable but I can't test the broadcast service. I get an error saying the service is not being called. How Should I access the service? Any help would be appreciated. Thank you.

This is my component with the observable:

  ngOnInit(): void {

    this.subscription.add(
      this.broadcastService.subscribe('msal:acquireTokenSuccess', (payload) => {
        // do something here
        this.roleService.checkServerEventReviewers().subscribe(res => {
          this.userService.userDetails.role = res ? 'Data Steward' : 'Mosaic Consumer';
          if (this.isLoggedIn !== true) {
            const redirectUri = sessionStorage.getItem('redirectUri');
            if (redirectUri !== undefined || redirectUri !== null) {
              this.router.navigateByUrl(redirectUri);
            }
          }
          this.isLoggedIn = true;
};

This is my spec file that I am trying:

  describe(':', () => {
    function setup() {
      const fixture = TestBed.createComponent(AppComponent);
      const app = fixture.debugElement.componentInstance;
      const compiled = fixture.debugElement.nativeElement;
      return {fixture, app, compiled};
    }

    it('Init with QA environment', () => {
      const {app} = setup();
      spyOn(app.authService, 'getUser').and.returnValue(mockData.userDetails);
      spyOn(app.authService, 'acquireTokenSilent').and.returnValue('msal:acquireTokenSuccess');
      app.ngOnInit();
      spyOn(app.broadcastService,'subscribe');
      expect(app.broadcastService.subscribe).toHaveBeenCalled();
    );