title: "Collection was modified; enumeration operation may not execute." in Unit Test Project
body: <p>I have an asp.net MVC project hosting a silverlight application.</p>
  
  <p>I just started rebuilding this project so there isn't much in it, just an authentication class and my entities classes(self tracking).</p>
  
  <p>The project runs, however as soon as I add a unit test to the asp.net project it fails with the following error
  "Collection was modified; enumeration operation may not execute."</p>
  
  <p>I'm familiar with this error, however I don't have any collections that I'm modifying, and the error is happening at compile time rather than run time. There is no line number or column, the error occurs in the Unit Test project. There are no other errors or warnings.</p>
  
  <p>I've deleted all my tests and I still get the error. I've deleted the test project and recreated it which hasn't helped. If I delete the .accessor file under test reference the project will build but as soon as I add another test the file is recreated and the error happens again.</p>
  
  <p>Anyone have any idea what the problem is?</p>