Faillure in Test Driven Development

Ionic Framework ionic-v3
1

Hello every one,

i train ionic framework using videos tutorial on youtube, i’m blocked in faillure error in my page tdd, this is the code of my app.component.spec.ts :

import { CUSTOM_ELEMENTS_SCHEMA } from '@angular/core';
import { TestBed } from '@angular/core/testing';

import { RouterModule } from '@angular/router';

import { AppComponent } from './app.component';

describe('AppComponent', () => {


  beforeEach(async () => {

    await TestBed.configureTestingModule({
      declarations: [AppComponent],
      schemas: [CUSTOM_ELEMENTS_SCHEMA],
      imports: [RouterModule.forRoot([])],
    }).compileComponents();
  });

  it('should create the app', () => {
    const fixture = TestBed.createComponent(AppComponent);
    const app = fixture.componentInstance;
    expect(app).toBeTruthy();
  });

  // TODO(ROU-10799): Fix the flaky test.
  xit('should have menu labels', () => {
    const fixture = TestBed.createComponent(AppComponent);
    fixture.detectChanges();
    const app = fixture.nativeElement;
    const menuItems = app.querySelectorAll('ion-label');
    expect(menuItems.length).toEqual(12);
    expect(menuItems[0].textContent).toContain('Inbox');
    expect(menuItems[1].textContent).toContain('Outbox');
  });

  it('should have urls', () => {
    const fixture = TestBed.createComponent(AppComponent);
    fixture.detectChanges();
    const app = fixture.nativeElement;
    const menuItems = app.querySelectorAll('ion-item');
    expect(menuItems.length).toEqual(12);
    expect(menuItems[0].getAttribute('ng-reflect-router-link')).toEqual('/folder/inbox');
    expect(menuItems[1].getAttribute('ng-reflect-router-link')).toEqual('/folder/outbox');
  });

});

and this is html page tdd errors :

4.6.1Options
finished in 0.803s
11 specs, 1 failure, 1 pending spec, randomized with seed 95927
Spec List | Failures
AppComponent > should have urls
Expected 0 to equal 12.
    at <Jasmine>
    at UserContext.apply (http://localhost:9876/_karma_webpack_/webpack:/src/app/app.component.spec.ts:42:30)
    at _ZoneDelegate.invoke (http://localhost:9876/_karma_webpack_/webpack:/node_modules/zone.js/fesm2015/zone.js:369:28)
    at ProxyZoneSpec.onInvoke (http://localhost:9876/_karma_webpack_/webpack:/node_modules/zone.js/fesm2015/zone-testing.js:2081:39)
    at _ZoneDelegate.invoke (http://localhost:9876/_karma_webpack_/webpack:/node_modules/zone.js/fesm2015/zone.js:368:34)
TypeError: Cannot read properties of undefined (reading 'getAttribute')
    at UserContext.apply (http://localhost:9876/_karma_webpack_/webpack:/src/app/app.component.spec.ts:43:25)
    at _ZoneDelegate.invoke (http://localhost:9876/_karma_webpack_/webpack:/node_modules/zone.js/fesm2015/zone.js:369:28)
    at ProxyZoneSpec.onInvoke (http://localhost:9876/_karma_webpack_/webpack:/node_modules/zone.js/fesm2015/zone-testing.js:2081:39)
    at _ZoneDelegate.invoke (http://localhost:9876/_karma_webpack_/webpack:/node_modules/zone.js/fesm2015/zone.js:368:34)
    at ZoneImpl.run (http://localhost:9876/_karma_webpack_/webpack:/node_modules/zone.js/fesm2015/zone.js:111:43)
    at runInTestZone (http://localhost:9876/_karma_webpack_/webpack:/node_modules/zone.js/fesm2015/zone-testing.js:216:38)
    at UserContext.<anonymous> (http://localhost:9876/_karma_webpack_/webpack:/node_modules/zone.js/fesm2015/zone-testing.js:234:32)
    at <Jasmine>

could you help me to resolve theses errors.