I am in trouble with unit testing in Visual Studio

Question

I am working on a simple project. I added unit test to it. When I choose "run all unit test" at the first time it work. But if I choose "run all unit test" at the second time, it pop ups an alert "Specified cast is not valid". If I made any modification in the test (even just hit a space) and save it then it works fine again. It is a littel bit strange behaviour and very annoying.

Is it a bug? Is there anyone already solved this?

Answer 1

Could be an issue generated by temporary files.

Try right clicking your solution and perform a "Clean solution" and then "Rebuild all".

Answer 2

A similar problem is reported: http://social.msdn.microsoft.com/Forums/vstudio/en-US/175cb376-9846-40fa-9197-50595cd32200/run-all-tests-results-in-specified-cast-is-not-valid?forum=vsunittest