<div class="child" (click)="testClick($event)"></div>

testClick(event) {
    console.log(event);
}

describe('AppComponent', () => {
  let fixture: ComponentFixture<AppComponent>;
  let app: AppComponent;
  let child: DebugElement;

  beforeEach(async(() => {
    TestBed.configureTestingModule({
      imports: [ ChildModule ],
      declarations: [
        AppComponent
      ],
    }).compileComponents();
  }));
  beforeEach(() => {
    fixture = TestBed.createComponent(AppComponent);
    app = fixture.debugElement.componentInstance;
    child = fixture.debugElement.query(By.css('.child'));
    fixture.detectChanges();
  });

  it(`should create the handle of the joystick'`, async(() => {
    expect(child).toBeTruthy();
  }));

  it(`clicks on the joystick handle and the relative Observable emits`, async(() => {
    setTimeout(() => {
      childHandle.triggerEventHandler('click', 'clicked');
    }, 100);

  }));

});

export class ChildComponent implements AfterViewInit {
  @ViewChild('child') private childElement: ElementRef;

  ngAfterViewInit() {
    const testClick$ = fromEvent(this.childElement.nativeElement, 'click');
    testClick$.subscribe(d => console.log('test click in child', d));
  }
}