Angular2 unit test service with Http call in constructor - unit-testing

Question

I am struggling to unit test Angular2 service which has async Http call in the constructor (now I wonder should it be here in the first place).
Example code below - the mocked call never seems to have been executed and I am not sure where should I put it in. The test fails as the property I am asserting is undefined at the time of execution. I tried with fakeAsync and tick() but that didnt work neither.
Service class:
#Injectable
export class Service {
private data: any; //some object that will be returned from server
constructor(private http: Http) {
this.http.get('url')
.map( (res: Response) => res.json())
.subscribe(res => this.data = res);
}
getId() {
return data.id;
}
}
The unit test:
describe('service test...', () => {
let service: Service;
let backend: MockBackend;
let result = { id: 123 };
beforeEach(() => {
TestBed.configureTestingModule({
imports: [HttpModule],
providers: [
Service,
{
provide: Http,
useFactory: (mockBackend, options) => {
return new Http(mockBackend, options);
},
deps: [MockBackend, BaseRequestOptions]
},
MockBackend,
BaseRequestOptions
]
});
});
beforeEach(inject([Service, MockBackend], (s, mb) => {
service = s;
backend = mb;
backend.connections.subscribe((conn) => {
conn.mockRespond(new Response(new ResponseOptions({body: result})));
});
}));
describe('test...', () => {
it('should have id of 123...', async(() => {
expect(service.getId()).toEqual(123);
}));
});
});