title: Evaluate color change with TestCafe
body: <p>To be independent of static text I want to check the RGB value of a selector.
  I found</p>
  
  <pre><code>const opacity = await selector.getStyleProperty('opacity');
  await t.expect(opacity).eql(1, {timeout: 5000})
  </code></pre>
  
  <p>The element to that will change is:</p>
  
  <pre><code>&lt;div class="cl-asset-wfstate" style="background-color: rgb(244, 159, 79);"&gt;&lt;/div&gt;
  
  &lt;div class="cl-asset-wfstate" style="background-color: rgb(92, 195, 55);"&gt;&lt;/div&gt;
  </code></pre>
  
  <p>So I tried </p>
  
  <pre><code>const bgcolour = await Selector('div.cl-asset-wfstate').getStyleProperty('background-color');
  await t.expect(bgcolour).eql('rgb(92, 195, 55)', {timeout: 5000})
  </code></pre>
  
  <p>But this does not work. The assertion will never be resolved.
  Any suggestion?</p>