title: HTML custom attribute not showing?
body: <p>Using a React app, i am currently addind custom attributes to HTML tags or React components for E2E tests (Testcafe)</p>
  <p>I am not sure why the extra <strong>data-test=&quot;burger-menu-btn&quot;</strong> is not showing up in any Element when i inspect the page ?</p>
  <pre><code> import {slide as Menu} from 'react-burger-menu';
   ...
  
   &lt;Menu className=&quot;sidebar-menu&quot; isOpen={menuOpen} data-test=&quot;burger-menu-btn&quot;&gt;
          &lt;Nav.Link onClick={() =&gt; goTo(&quot;/dashboard&quot;)}&gt;
          ...
   &lt;/Menu&gt;
  </code></pre>
  <p>Its also the case for regular HTML tags such as</p>
  <pre><code>&lt;button className={&quot;redirect-button&quot;} data-test=&quot;return-dashboard-btn&quot;&gt;Return&lt;/button&gt;
  </code></pre>
  <p>Thus testcafe is not able to find the button with <code>await Selector('[data-test=&quot;return-dashboard-btn&quot;]');</code></p>
  <p>The app is served either through webpack-dev-server or a webpack bundle</p>
  <p>I don't think webpack removes any HTML attributes, not sure why they are gone.</p>