[Angular Unit Testing] Debug unit testing -- component rendering

If sometime you want to log out the comonent html to see whether the html render correctly, you can do :

import {TestBed, async, ComponentFixture} from '@angular/core/testing';
import {AppComponent} from './app.component';
import {AuFaInputComponent} from './lib/au-fa-input/au-fa-input.component';
import {InputRefDirective} from './lib/common/input-ref.directive';
import {DebugElement} from '@angular/core';
import {By} from '@angular/platform-browser';
 
describe('AppComponent', () => {
 
  let component: AppComponent,
    fixture: ComponentFixture<AppComponent>,
    el: DebugElement,
    emailField: DebugElement;
 
  beforeEach(async(() => {
    TestBed.configureTestingModule({
      declarations: [
        AppComponent, AuFaInputComponent, InputRefDirective
      ],
    }).compileComponents();
  }));
 
  beforeEach(() => {
 
    fixture = TestBed.createComponent(AppComponent);
    component = fixture.debugElement.componentInstance;
    el = fixture.debugElement;
    emailField = el.query(By.css('#email-field'));
 
    fixture.detectChanges();
  });
 
  it('should include the correct email icon inside the email input', async() => {
    // debug a component html
    console.log(emailField.nativeElement.outerHTML);
    expect(emaailField.query(By.css('i.icon.fa.fa-envelope'))).toBeTruthy();
  });
});

If you found that some tmeplate binding doesn't render, you might should add :

fixture.detectChanges();

to trigger change detection.