Angular 2 unit testing "Cannot read property 'unsubscribe' of undefined"

Question

I have sample TestComp with ngOnInit and ngOnDestroy methods and ActivatedRoute subscription.

@Component({
    selector: 'test',
    template: '',
})
export class TestComp implements OnInit, OnDestroy {

    constructor (
        private route: ActivatedRoute
    ) {
    }

    ngOnInit() {
        this.subscription = this.route.data
            .subscribe(data => {
                console.log('data', data.name);
            })
        ;
    }

    ngOnDestroy() {
        this.subscription.unsubscribe();
    }
}

I am getting "Cannot read property 'unsubscribe' of undefined" when I call ngOnDestroy method from spec file (or when I am running multiple tests).

My spec file:

describe('TestComp', () => {
    let comp: TestComp;
  let fixture: ComponentFixture<TestComp>;

  beforeEach(async(() => {
    TestBed
    .configureTestingModule({
      declarations: [TestComp],
      imports: [RouterTestingModule],
      providers: [
        {
        provide: ActivatedRoute,
        useValue: {
          data: {
            subscribe: (fn: (value: Data) => void) => fn({
              name: 'Stepan'
            })
          }
        }
      }
        // { //Also tried this
        //   provide: ActivatedRoute,
        //   useValue: {
        //     params: Observable.of({name: 'Stepan'})
        //   }
        // }
      ]
    })
    .compileComponents()
    .then(() => {
          fixture = TestBed.createComponent(TestComp);        
          fixture.detectChanges();
    })
    }));

  it('TestComp successfully initialized', () => {
    fixture.componentInstance.ngOnInit();
    expect(fixture.componentInstance).toBeDefined()
    fixture.componentInstance.ngOnDestroy();
  });
});

I am passing ActivatedRoute value based on answers here, but I am getting error. So my question is - what should I pass as ActivatedRoute to make it possible to subscribe and unsubscribe? Example Plunker.

it's a good practice to put a conditional `if (this.subscription)` around the unsubscription. I've just tried the testcode and put a `setTimeout` of 500ms on the ngOnDestroy function call in your test and then the test passes. I guess it takes some time until the subscription is actually initialised. — Jacob Notte, Feb 10 '17 at 07:38
@JacobNotte This worked for me! Had just to ensure that `this.subscription` was not `undefined`! — SrAxi, Mar 01 '17 at 13:23

score 2 · Accepted Answer · answered Feb 10 '17 at 08:24

2

Just use observer when mock your service:

{
    provide: ActivatedRoute,
    useValue: { data: Observable.of({ name: 'Stepan' }) }
}

answered Feb 10 '17 at 08:24

VadimB

5,533
2
34
48

Thanks for answer, I tried ``params: Observable.of({name: 'Stepan'})`` instead of ``data: Observable.of({ name: 'Stepan' })``, now its working fine. – styopdev Feb 10 '17 at 11:05

score 1 · Answer 2 · answered Feb 10 '17 at 08:18

1

You should import Subscription first.

import { Subscription } from 'rxjs/Subscription';

answered Feb 10 '17 at 08:18

Mertcan Diken

14,483
2
26
33

Angular 2 unit testing "Cannot read property 'unsubscribe' of undefined"

2 Answers2