title: How to clear previous expectations on an object?
body: <p>I would like to set up a return value</p>
  
  <pre><code>_stubRepository.Stub(Contains(null)).IgnoreArguments().Return(true);
  </code></pre>
  
  <p>but then in a specific test, override that expectation to return false.  </p>
  
  <p>Something like:</p>
  
  <pre><code>_stubRepository.ClearExpectations();  //&lt;- this does not exist, I'm just making something up
  _stubRepository.Stub(Contains(null)).IgnoreArguments().Return(false);
  </code></pre>
  
  <p>Notice, I do not want the expectation to return false on the second call, I want to override the first expectation.</p>
  
  <p>This would help simplify my testing scenario greatly.</p>