title: Node mocha array should contain an element
body: <p>I want to do a simple assertion of something like</p>
  
  <pre><code>knownArray.should.include('known value')
  </code></pre>
  
  <p>The array is correct, but I simply can't figure out the proper assertion to use to check whether the array has this value (the index doesn't matter).  I also tried <code>should.contain</code> but both of these throw an error that <code>Object #&lt;Assertion&gt; has no method 'contain'</code> (or <code>'include'</code>)</p>
  
  <p>How can I check that an array contains an element using <code>should</code>?</p>