Unit Testing window.keyDown event Angular2 Karma Unit testing

Testing an event is one of the fascinating parts of unit testing. You are creating an event without even going to the screen.

In the series of Event Testing, I am going to tell you about testing a keyDown event on window.

I am not going into a detailed description of creating a component or writing a test file. Just explaining the methods:

In Test-component.ts

// Listen keyboard shortcuts@HostListener('window:keydown', ['$event'])
onKeyDown( event ) {
  // Esc button click  if (event.keyCode === 27 && event.code === 'Escape') {
    this.eventFired = true;
  }
}

In Test-component.spec.ts

it('should fire window keydown event', () => {
    const event: Event = new KeyboardEvent('keydown', {
      'code': 'Escape' //Code for the key
    });
    window.dispatchEvent(event);
    fixture.detectChanges();
    expect(component.eventFired).toBeTruthy();
  });

If you want any detailed description, please tell me in the comments below.