Testing Effects

import { TestBed } from '@angular/core/testing';
import { provideMockActions } from '@ngrx/effects/testing';
import { cold, hot } from 'jasmine-marbles';
import { Observable } from 'rxjs';

import {
  InsertUser,
  InsertUserSuccess,
  InsertUserFail
} from './user.actions';
import { generateUser, generateUserArray } from '../../core/user';
// TODO: Change this path when you move your service file:
import { UserService } from '../../core/user.service';
import { UserEffects } from './user.effects';

describe('UserEffects', () => {
  let actions: Observable<any>;
  let effects: UserEffects;
  let service;

  beforeEach(() => {
    TestBed.configureTestingModule({
      providers: [
        UserEffects,
        provideMockActions(() => actions),
        {
          provide: UserService,
          useValue: { create: jest.fn() }
        },
      ]
    });

    effects = TestBed.get(UserEffects);
    service = TestBed.get(UserService);
  });

  it('should be constructed', () => {
    expect(effects).toBeTruthy();
  });

  // Effect Test
  describe('insert', () => {
    it('should return InsertUserSuccess action with entity on success', () => {
      const entity = generateUser(),
        insertAction = new InsertUser({ user: entity }),
        successAction = new InsertUserSuccess({ result: entity }),
        response = cold('-b|', { b: entity }),
        expected = cold('-s', { s: successAction });

      actions = hot('a-', { a: insertAction });

      service.create = jest.fn(() => response);

      expect(effects.insert).toBeObservable(expected);
    });
  });

  // Effect Test - Failure Path
  it('should return InsertUserFail with error object on failure', () => {
    const entity = generateUser(),
      insertAction = new InsertUser({ user: entity }),
      failAction = new InsertUserFail({ error: 'fail' }),
      response = cold('-#|', {}, { message: 'fail' }),
      expected = cold('-f', { f: failAction });

    actions = hot('i-', { i: insertAction });

    service.create = jest.fn(() => response);

    expect(effects.insert).toBeObservable(expected);
  });
});

Write tests for Tour of Heroes:

https://stackblitz.com/github/jessesanders/tour-of-heroes/tree/ngrx-entity