Unit Tests In Angular2 - part 2 (The Component)

Testing The Component

In previous post we've learned how to test the model (Simple javascript object) and the Service in angular2. Now I think' we ready for next step:

How To Test The Component

Lets say we have a User Component which should display the full name of some user:
(user-component.ts):

import { Component,  Input} from '@angular/core';
import {UserModel} from './user-model'
@Component({
    selector: 'user-component',
    template:   `{{ user.fullname() }}`
})
export class UserComponent {
    @Input() user:UserModel;
}

This component contains @input annotation - which means the parameter from outside (named user) should be set

The Test

As in case of Service we should start with setup the module with testBed util:
(user-component.spec.ts):

import {UserComponent} from './user-component'
import {UserModel} from './user-model'
import { async, ComponentFixture, TestBed } from '@angular/core/testing';
import { By }           from '@angular/platform-browser';
import { DebugElement } from '@angular/core';

describe('UserComponent tests', function () {
  let de: DebugElement;
  let comp: UserComponent;
  let fixture: ComponentFixture;

  beforeEach(async(() => {
    TestBed.configureTestingModule({
      declarations: [  UserComponent ]
    })
    .compileComponents();
  }));

  beforeEach(() => {
    fixture = TestBed.createComponent(UserComponent);
    comp = fixture.componentInstance;
    comp.user = new UserModel('Vasia','Kozlov')// <--here we passing the outer parameter
    de = fixture.debugElement.query(By.css('span'));
  });

  it('should create component', () => expect(comp).toBeDefined() );

  it('should have fullname of user displayed inside "span" tag', () => {
    fixture.detectChanges();
    const h1 = de.nativeElement;
    expect(h1.innerText).toMatch(/Vasia Kozlov/i,
      ' should state user Full Name');
  });
});

As you can see - the outer parameter passed using fixture.componentInstance helper
You can view the running code on the plunker