title: XNA project unit testing, builds but errors running tests
body: <p>I'm trying to set up some unit tests for an XNA project. After some ordeals with making sure the test project was set to build in the configuration manager and removing references to the XNA content project, I finally got the tests to build.</p>
  
  <p>But the tests still won't run half of the time. If I click "run selection" from the test view I continually get the error "No such interface supported (Exception from HRESULT:0x80004002 (E_NOINTERFACE))." If I instead press the "run all tests in solution" button, it sometimes runs, but usually it gives me this error: "Specific Cast is not Valid." if run all tests does work the first time (this seems to happen after updating from SVN), it stops working immediately after that.</p>
  
  <p>I've found some people with similar issues:</p>
  
  <p><a href="http://connect.microsoft.com/VisualStudio/feedback/details/602985/unit-testing-does-not-work-with-xna-4-0" rel="nofollow">http://connect.microsoft.com/VisualStudio/feedback/details/602985/unit-testing-does-not-work-with-xna-4-0</a></p>
  
  <p><a href="http://social.msdn.microsoft.com/Forums/en-US/vsunittest/thread/175cb376-9846-40fa-9197-50595cd32200/" rel="nofollow">http://social.msdn.microsoft.com/Forums/en-US/vsunittest/thread/175cb376-9846-40fa-9197-50595cd32200/</a></p>
  
  <p>But both seemed to have died without resolutions. Any help would be appreciated.</p>