title: PHPUnit, mocked interfaces, and instanceof
body: <p>Sometimes in my code, I'll check to see if a particular object implements an interface:</p>
  
  <pre><code>if ($instance instanceof Interface) {};
  </code></pre>
  
  <p>However, creating mocks of said interface in PHPUnit, I can't seem to pass that test.</p>
  
  <pre><code> // class name is Mock_Interface_431469d7, does not pass above check
   $instance = $this-&gt;getMock('Interface'); 
  </code></pre>
  
  <p>I understand that having a class named Interface is different from a class implementing Interface, but I'm not sure how to get deal with this.</p>
  
  <p>Am I forced to mock a concrete class that implements Interface? Wouldn't that defeat the purpose of using an interface for portability?</p>
  
  <p>Thanks</p>