I’m trying to write a negative test for my AuthService that a property in the constructor is set to null if nothing is returned from angularFireAuth. The positive side of this test case is working, and if I modify my mock file directly I can see the outcomes I want. Even with the spyOnProperty mock I have below, when I subscribe to it I can see in console logs that it’s returning null.

The problem is that I can’t get the actual service constructor to pick up the spyOnProperty returnValue. For a component I would do a fixture.detectChanges but that doesn’t work for a service. Is there some way I have to rebuild the service before the constructor picks up the mocked null value?

AuthService Constructor

{
(this.partyCollectionPath);
    this.afAuth.authState.subscribe((user: User | null) => {
      if (user) {
        this.userData = {
          uid: user.uid,
          email: user.email,
          emailVerified: user.emailVerified
        };
        this.liveUid = user.uid
      } else {
        this.userData = null
      }
    });
  }

AngularFireAuthMock

import { User } from '../shared/interface/user';
import { of } from 'rxjs';

const authState: User = {
    uid: 'fakeuser',
    email: '[email protected]',
    emailVerified: true
};
export const AngularFireAuthMock: any = {
    AngularFireAuth: jasmine.createSpyObj('AngularFireAuth', {
//other functions
}),

get authState() {
    return of(authState);
  },

Test Assertion

  it('userData set to null', () => {

    const spy = spyOnProperty(AngularFireAuthMock, 'authState', 'get');
    spy.and.returnValue(of(null))

    AngularFireAuthMock.authState.subscribe((data: any) => {
      
      console.log('subscribe: ', data)
      
    })
    console.log('userData: ', service.userData) 
    // expect(service.userData).toBeNull()

  });

Console Logs

LOG: ‘subscribe: ‘, null

LOG: ‘userData: ‘, Object{uid: ‘fakeuser’, email: ‘[email protected]’,
emailVerified: true}