title: What is the difference between Moq-ing a class or interface?
body: <p>I've been using <a href="http://code.google.com/p/moq/" rel="noreferrer">moq</a> to mock objects in my unit tests and I've seen on the site about moq that it is able to mock both classes and interfaces.</p>
  
  <p>I had a discussion with one of my work mates the other day and they stated that there is never a reason to mock classes and I should only mock interfaces.</p>
  
  <p>I didn't really have an answer to that....and I can't seem to find any answer to that on the moq site either. </p>
  
  <p>Is it true that one should never mock classes? I'd say no since if that were true then Moq wouldn't even allow it....So then is there a time where it is better to mock a class over an interface? What is the difference between mocking a class vs mocking an interface? Or does it really just a preference thing?</p>