Unit test within async using fixture.detectChanges() fails

Riproduci il fallimento con npm run test-ci dopo aver esaminato src/app/app.component.spec.ts e src/app/app.component.ts, incluso l’async test e la configurazione di rootPage. Traccia il rifiuto non valido di Page1 attraverso la configurazione dei test Angular/Ionic; il lavoro è completato quando fixture.detectChanges() nell’async test mostrato non produce più l’errore di una promise non gestita.

Hello,

This is the issue description:
Using the method from ComponentFixture .detectChanges() is failing when you use it within an async() unit test.

How to reproduce:

1. Clone this repo: git clone https://github.com/ionic-team/ionic-unit-testing-example.git
2. Install packages: cd ionic-unit-testing-example && sudo npm install
3. Add the following unit test to the src/app/app.component.spec.ts:

  it( 'example test async with fixture.detectChanges()', async(() => {
    fixture.detectChanges();
  }));

4. Run tests: npm run test-ci

After running the tests, it fails with the following error:

..ERROR: 'Unhandled Promise rejection:', 'invalid link: Page1', '; Zone:', 'angular', '; Task:', 'Promise.then', '; Value:', 'invalid link: Page1', undefined

ERROR: 'Unhandled Promise rejection:', 'invalid link: Page1', '; Zone:', 'angular', '; Task:', 'Promise.then', '; Value:', 'invalid link: Page1', undefined
Chrome 65.0.3325 (Linux 0.0.0) MyApp Component example test async with fixture.detectChanges() FAILED
        Failed: Uncaught (in promise): invalid link: Page1
        Error: Uncaught (in promise): invalid link: Page1
            at resolvePromise (webpack:///node_modules/zone.js/dist/zone.js:824:0 <- test-config/karma-test-shim.js:117151:31)
            at Object.reject (webpack:///node_modules/zone.js/dist/zone.js:746:0 <- test-config/karma-test-shim.js:117073:17)
            at NavControllerBase._fireError (webpack:///node_modules/ionic-angular/navigation/nav-controller-base.js:223:0 <- test-config/karma-test-shim.js:51342:16)
            at NavControllerBase._failed (webpack:///node_modules/ionic-angular/navigation/nav-controller-base.js:216:0 <- test-config/karma-test-shim.js:51335:14)
            at webpack:///node_modules/ionic-angular/navigation/nav-controller-base.js:263:44 <- test-config/karma-test-shim.js:51382:59
            at ZoneDelegate.invoke (webpack:///node_modules/zone.js/dist/zone.js:392:0 <- test-config/karma-test-shim.js:116719:26)
............

Expected result should be at least not to throw this error when using fixture.detectChanges().

The full src/app/app.component.spec.ts file would be as the following:

import { async, TestBed, fakeAsync, ComponentFixture, tick } from '@angular/core/testing';
import { IonicModule, Platform, MenuController, Menu } from 'ionic-angular';

import { StatusBar } from '@ionic-native/status-bar';
import { SplashScreen } from '@ionic-native/splash-screen';

import { MyApp } from './app.component';
import {
  PlatformMock,
  StatusBarMock,
  SplashScreenMock
} from '../../test-config/mocks-ionic';
import { Page } from 'ionic-angular/navigation/nav-util';
import { By } from '@angular/platform-browser';

describe('MyApp Component', () => {
  let fixture;
  let component;

  beforeEach(async(() => {
    TestBed.configureTestingModule({
      declarations: [MyApp],
      imports: [
        IonicModule.forRoot(MyApp)
      ],
      providers: [
        { provide: StatusBar, useClass: StatusBarMock },
        { provide: SplashScreen, useClass: SplashScreenMock },
        { provide: Platform, useClass: PlatformMock }
      ]
    });
  }));

  beforeEach(() => {
    fixture = TestBed.createComponent(MyApp);
    component = fixture.componentInstance;
  });

  it('should be created', () => {
    expect(component instanceof MyApp).toBe(true);
  });

  it('should have two pages', () => {
    expect(component.pages.length).toBe(2);
  });

  it( 'example test async with fixture.detectChanges()', async(() => {
    fixture.detectChanges();
  }));

});

Doest anyone at least know why this could be happenning? I don't know if this could even be an Angular bug with lazy loading or whatever.

The only reference to Page1 is inside src/app/app.component.ts in order to set up the page as the rootPage of the app:

import { Component, ViewChild } from '@angular/core';
import { SplashScreen } from '@ionic-native/splash-screen';
import { StatusBar } from '@ionic-native/status-bar';
import { Nav, Platform, Menu } from 'ionic-angular';


@Component({
  templateUrl: 'app.html'
})
export class MyApp {
  @ViewChild(Nav) nav: Nav;

  rootPage: any = 'Page1';

  pages: Array<{ title: string, component: any }>;


  constructor(public platform: Platform, public statusBar: StatusBar, public splashScreen: SplashScreen) {
    // used for an example of ngFor and navigation
    this.pages = [
      { title: 'Page One', component: 'Page1' },
      { title: 'Page Two', component: 'Page2' }
    ];

  }

  ionViewDidLoad() {
    this.platform.ready().then(() => {
      // Okay, so the platform is ready and our plugins are available.
      // Here you can do any higher level native things you might need.
      this.statusBar.styleDefault();
      this.splashScreen.hide();
    });
  }

  openPage(page) {
    // Reset the content nav to have just this page
    // we wouldn't want the back button to show in this scenario
    this.nav.setRoot(page.component);
  }

}

Thank you in advance.

Regards,

David.