title: Angular: How I can test @HostListener in jasmine?
body: <p>I have the next code in angular's component:</p>
  
  <pre><code>@HostListener('window:scroll', []) onWindowScroll() {
    this.showScrollToTop = false;
  }
  </code></pre>
  
  <p>How can I test this in jasmine? How to to initiate window scroll event?</p>