In my component inside ngOnInit I have a subscribe() inside which I call a component function:
ngOnInit(): void {
this.navigationService.itemReset$.subscribe(event => this.resetItem(event));
}
in the navigationService I have:
btnPressed$: Subject<Event> = new Subject();
itemReset$: Observable<Event> = this.btnPressed$.asObservable();
keyDown(event: Event): void {
this.btnPressed$.next(event);
}
I searched a lot about this issue, and tried something like this in my component test:
describe('MyComponent', () => {
let component: MyComponent;
let fixture: ComponentFixture<MyComponent>;
let navigationServiceMock = {
itemReset$: () => of({} as Event),
// tried this: itemReset$: jasmine.createSpy('itemReset$').and.returnValue(of({})),
};
beforeEach(async () => {
await TestBed.configureTestingModule({
declarations: [MyComponent],
providers: [{
provide: navigationService,
useValue: navigationServiceMock
}]
})
.compileComponents();
});
beforeEach(() => {
fixture = TestBed.createComponent(MyComponent);
component = fixture.componentInstance;
fixture.detectChanges();
});
it('should create', () => {
expect(component).toBeTruthy();
});
});but still, get the error
TypeError: this.navigationService.itemReset$.subscribe is not a function
Any idea, why it doesn't work? I would be really grateful for any help!
Ensure that the type of itemReset$ in your fake object matches the type in the implementation.
You need to pass a Observable<Event> but you had a function returning such an observable instead.
let navigationServiceMock = {
itemReset$: of({} as Event),
};
You are close but remember you are mocking:
let navigationServiceMock = {
itemReset$: () => of({} as Event),
// tried this: itemReset$: jasmine.createSpy('itemReset$').and.returnValue(of({})),
};
You have a mocked a function called itemReset$ which returns an observable.
In reality, you want itemReset$ to be the observable.
So change your mock to:
let navigationServiceMock = {
itemReset$: of({} as Event),
};