CODEWITHSUNDEEP
angularunit-testingtypescriptjasmine
George Edwards
George Edwards

Reputation: 9229

Angular service's properties aren't setup on creation

I am trying to test the following angular (4.1) service:

@Injectable()
export class JobService {
  private answerSource = new Subject<AnswerWrapper>();
  answer$ = this.answerSource.asObservable(); 

  answer(answer: AnswerWrapper) {
    this.answerSource.next(answer);
  }

which I am testing with this unit-test:

  beforeEach(() => {
    TestBed.configureTestingModule({
      providers: [JobService]
    });
  });

  it('should emit $answer on answer()', inject([JobService], (service: JobService) => {
    service.answer$.subscribe(val => expect(val).toEqual('test123'));
    service.answer(('test123' as any))
  }));

However, I get the error:

Cannot read property 'subscribe' of undefined

I really can't see why it would be undefined, as it should be setup on service creation?

Upvotes: 0

Views: 23

Answers (1)

Dean Chalk
Dean Chalk

Reputation: 20471

you need to put this line in a constructor

answer$ = this.answerSource.asObservable();

The answerSource Subject is guaranteed to be initialised before the constructor is run

Upvotes: 1

Related Questions