angular2 testing using jasmine for subscribe method

Question

I have a spec code to test like this

 it(\'login test\', () => {

      const fixture = TestBed.createComponent(component);
      fixture.detectChanges();         


        

Answer 1

On rxjs v6 you should use of instead of Observable.of or Observable.from e.g

const loginService: any = {
    getUser: () => of(['Adam West']),
};

and import

import { of } from 'rxjs';

Answer 2

Change your spy for the 'login' method on your authService to return an observable instead of a value. You'll need to import:

import 'rxjs/add/observable/from';
import {Observable} from 'rxjs/Observable';

Setup your spy:

const loginResult = '';
const spy = spyOn(authService, 'login').and.callFake(() => {
    return Observable.from([loginResult]);
})

Call login:

fixture.componentInstance.login();

Assert:

expect(spy).toHaveBeenCalled();

Answer 3

You need to mock the login function as follows:

let loginService: any = {
    login(): Observable<any> {
        return Observable.of('you object');
    }
};

you might find the observable.if function undefined, so you need to import the observable this way:

import { Observable } from 'rxjs/Rx';
import 'rxjs/add/observable/of';

Answer 4

You need to return something with a subscribe method, as the component calls subscribe directly from login. A string does not. You could just return an object with a subscribe function and it should work

and.returnValue({ subscribe: () => {} });

Or if you want to pass a real observable, you could

and.returnValue(Observable.of('some value'));

You might need to import rxjs/add/observable/of