I have a karma unit test and the test fails with below error.
this.gridApi.getScaleWidth().subscribe is not a function
GridApi.ts
export class GridApi {
private scaleWidthSubject = new BehaviorSubject<{value: number}>({value: 0});
public getScaleWidth(): Observable<{value:number}> {
return this.scaleWidthSubject;
}
}
GridComponent.ts
export class GridComponent implements OnInit, OnDestroy, AfterViewInit {
private subscribeToValueChanges() {
this.scaleWidth$ = this.gridApi.getScaleWidth().subscribe( width => {
this.scaleWidth = width.value;
});
}
}
Component.spec.ts
describe('GridComponent', () => {
beforeEach(async () => {
const mockGridApiService = jasmine.createSpyObj("GridApi", {
getScaleWidth () : Observable<{value: number}> {
let scaleWidthSubject = new BehaviorSubject<{value: number}>({value: 0});
return scaleWidthSubject.asObservable();
}
});
}
await TestBed.configureTestingModule({
providers: [ { provide: GridApi, useValue: mockGridApiService} ],
imports: [
HttpClientModule
],
declarations: [ GridComponent ]
})
}
What should the mock getScaleWidth() return to pass the test. Not sure what I'm missing here.
describe('GridComponent', () => {
const mockGridService = jasmine.createSpyObj<GridApi>('GridApi', ['getScaleWidth'])
beforeEach(() => {
mockGridService.getScaleWidth.and.returnValue(of({ value: 0 }));
});
await TestBed.configureTestingModule({
providers: [ { provide: GridApi, useValue: mockGridService} ],
imports: [HttpClientModule],
declarations: [ GridComponent ]
})
it('should call getScaleWidth from service', () => {
// the component function that triggers the service call is private
// make the call from component
expect(mockGridService.getScaleWidth).toHaveBeenCalled();
mockGridService.getScaleWidth().subscribe(response => {
expect(response.value === 0)
})
})
}