src/app/common-components/remove-button/remove-button.component.spec.ts

import { async, ComponentFixture, TestBed } from '@angular/core/testing';

import { RemoveButtonComponent } from './remove-button.component';

describe('RemoveButtonComponent', () => {
  let component: RemoveButtonComponent;
  let fixture: ComponentFixture<RemoveButtonComponent>;

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

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

  it('should set the bound model to null', async(() => {
    let emit = false;
    expect(component).toBeTruthy();
    fixture.detectChanges();
    component.nullableAttribute = 'INIT TEXT';
    component.nullableAttributeChange.subscribe( changedText => emit = ( changedText === null));

    component.clear();

    fixture.whenStable().then( () => {
      expect( emit ).toBeTruthy();

    });
  }));
});