title: XMLHttpRequest testing in Jest
body: <p>I want to test AJAX methods (vanilla XHR) and I can't find the way to do it with <strong>Jest</strong> framework. I found <code>mock-ajax.js</code> for Jasmine. The problem is I can't find the way to install it.</p>
  <p>Is there maybe a better way to unit test Ajax functions in <strong>Jest</strong>?</p>