Jasmine/Angular2 testing Observable passing unexpectedly

Question

I'm trying to test a class that makes HTTP calls, mocking out the calls. I haven't actually set up my mock HTTP call yet so I would expect the test to fail, but it passes. How do I get the test to fail if the Observable doesn't return anything?

Here's my test:

describe('my service', () => {
  beforeEach(() => {
    TestBed.configureTestingModule({
      imports: [HttpModule],
      providers: [
        MyService,
        { provide: XHRBackend, useClass: MockBackend }
      ]
    });
  });

  it('should return a Candidate', async(inject([MyService], (service: MySerivce) => {
    // given
    const candidateId = 'test@test.com';

    // when
    service.getCandidate(candidateId).subscribe(candidate => {
        expect(candidate.Id).toBe(candidateId);
        // will have some other assertions here
    });
  })));
});

The MyService.getCandidate method does something like this:

public getCandidate(candidateId: string): Observable<Candidate> {
  const url = '<my url>';
  return this.http.get(url)
    .map(this.parseCandidate);
}