title: How can I check if an element's class is active in protractor?
body: <p>I have the following code:</p>
  
  <p>View:</p>
  
  <pre><code>&lt;li class="active"&gt; 
      &lt;a href="#public1' data-toggle="tab"&gt; All Stacks &lt;/a&gt;
  &lt;/li&gt;
  </code></pre>
  
  <p>I can locate the element (tab) in the following manner:</p>
  
  <pre><code>var allStacksTab = element(by.linkText("All Stacks"));
  </code></pre>
  
  <p>Now how can I test, using the expect() --to see if that element/tab has the active class?</p>