Test Subscription on ngrx selector inside component constructor

some-menu.service.ts

@Injectable()
export class SomeMenuService {

  buildMobileMainMenu(descData: DataForMenuDescriptions) {
    return { menu: 'menu' };
  }
}

some-store.service.ts

@Injectable()
export class SomeStoreService {
  mobileMenuDescriptions$: Observable<DataForMenuDescriptions> = this._store.select(selectMobileMenuDescriptions);

  constructor(private _store: Store<AppState>) { }
}

some.service.test.ts

import { ActionsSubject } from '@ngrx/store';

const mockData = { somedata: 'somedata' };

const storeServiceStub = {
  mobileMenuDescriptions$: new Subject(),
} as unknown as DashboardStoreService;

const menuMapServiceStub = {
  buildMobileMainMenu: jest.fn().mockImplementation((data) => ({ data })),
} as unknown as MenuMapService;

const actionsSubjectMock = new ActionsSubject();

describe('SomeService', () => {
  const service = new SomeService(
    storeServiceStub,
    menuServiceStub,
    actionsSubjectMock,
  );

  describe('init', () => {
    it('should return properly value on mobileMenuDescSubs$ subscribe', () => {
      const spyMobileMenuNext = jest.spyOn(service.mobileMenu$, 'next');
      (service.store.mobileMenuDescriptions$ as unknown as Subject<DataForMenuDescriptions>).next(mockData as unknown as DataForMenuDescriptions);
      expect(menuServiceStub.buildMobileMainMenu).toHaveBeenCalledWith(mockData);
      expect(spyMobileMenuNext).toHaveBeenCalledWith({ data: mockData });
    });

    it('should return properly value on actionsSubject$ subscribe', () => {
      expect(service.isExternalNavigation).toEqual(false);
      const action = { type: 'GoSomePage' };
      actionsSubjectMock.next(action);
      expect(service.isExternalNavigation).toEqual(true);
    });
  });
        
});

some.service.ts

@Injectable()
export class SomeService {

  private _mobileMenuDescSubs$: Subscription;
  private _mobileMenu$ = new BehaviorSubject<MenuItem[]>([]);
  private _isExternalNavigation = false;

  constructor(
    private _store: SomeStoreService,
    private _menuService: SomeMenuService,
    public _actionsSubject$: ActionsSubject,
  ) {
  
    // TRY TO TEST THIS
    this._mobileMenuDescSubs$ = this._store.mobileMenuDescriptions$.subscribe((dataForDescriptions: DataForMenuDescriptions) => {
      this._mobileMenu$.next(this.buildMobileMenu(dataForDescriptions));
    });
    
    // AND TRY TO TEST THIS
    this._actionsSubject$.subscribe(({ type }) => {
      if (type === 'GoSomePage') {
        this.isExternalNavigation = true;
      }
    });
  }
  
  set isExternalNavigation(value) {
    this._isExternalNavigation = value;
  }

  get isExternalNavigation() {
    return this._isExternalNavigation;
  }
  
  private buildMobileMenu(dataForDescriptions: DataForMenuDescriptions) {
    return this._menuService.buildMobileMenu(dataForDescriptions);
  }
}