I’m trying to mock/test SendVerificationMail() from my AuthService, which starts by calling the AngularFireAuth method currentUser which returns an angularFire User object, which you can then use to call sendEmailVerification(). I’ve tried a few different mocking methods, but I just end up with the errors below because it can’t find user.sendEmailVerification

Error

    Error: Uncaught (in promise): TypeError: user.sendEmailVerification is not a function
    TypeError: user.sendEmailVerification is not a function

AuthService

  SendVerificationMail() {
    return this.afAuth.currentUser
      .then((user: any) => {user.sendEmailVerification(),})
      .then(() => {
        this.router.navigate(['verify-email-address']);
      });
  }

AngularFireAuth Mock File

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

const authState: User = {
    uid: 'fakeuser',
    email: '[email protected]',
    emailVerified: true
};

export const AngularFireAuthMock: any = {
    createUserWithEmailAndPassword: () => {
        return Promise.resolve(userCredential)
    },

    sendEmailVerification: () => {
        return Promise.resolve()
    },

    AngularFireAuth: jasmine.createSpyObj('AngularFireAuthMock', {
        'sendEmailVerification': {
            function() {
                return Promise.resolve({
                    code: 'auth/user-not-found'
                })
            }
        }
    }

    ),

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

    get user() {
        return this.authState;
    },

    get currentUser() {
        return Promise.resolve(userCredential)
    }
}

auth.service.spec.ts

it('SendVerificationMail() - Functions Called', fakeAsync(() => {
  const spySendEmailVerification = spyOn(AngularFireAuthMock, 'sendEmailVerification')
  service.SendVerificationMail()

  tick();

  expect(spySendEmailVerification).toHaveBeenCalled()
  
}));