Cannot read property unsubscribe of undefined: Angular2 testing

Question

I am trying to test a component which has ngOnDestroy() method which has all the unsubscribe() method calls. But, while testing, when I run my testing file (spec file) it gives me error saying: ``` cannot read property 'unsubscribe' of undefined ``` I have done the following import in my testing file: ``` import { Subscription } from 'rxjs/Subscription'; ``` so I think this should be enough to get all the methods in Subscription, but still the error is there. Also, I tried adding 'Subscription' to my 'imports', 'declarations' and 'providers' list of the testing file, still the error is there. Below is a code snippet: ``` //component import { Component, OnInit, OnDestroy } from '@angular/core'; import { Subscription } from 'rxjs/Subscription'; import { NinjaService } from '../../../../ninja.service'; @Component({ selector: 'ninja-files', templateUrl: './ninja-files.component.html', styleUrls: ['./ninja-files.component.css'] }) export class ninjaFilesComponent implements OnInit, OnDestr…

Accepted Answer

```
import { Subscription } from 'rxjs/Subscription';
```

All this means is that you can access the `Subscription` class from the `ninjaFilesComponent` class file.

The problem is that the `addFileSubscription` is never initialized. In order for the `ngOnInit` to be called, you need to call

```
fixture.detectChanges();
```

Aside from that, the other problems I see are:

You never add the stub to the providers

```
TestBed.configureTestingModule({
  providers: [
    { provide: NinjaService, useValue: ninjaServiceStub }
  ]
})
```

You need to actually implement something in the stub

```
let ninjaServiceStub = {
  AddedFile$: Observable.of(new FileFormat(...))
}
```

You're not using the service in the component correctly

```
this.NinjaService.AddedFile$
// should be
this.ninjaService.AddedFile$
// lowercase
```

Cannot read property unsubscribe of undefined: Angular2 testing

Solution

Problem