Visual Studio 2013 doesn't discover unit tests

Question

I have a simple solution in visual studio 2013 that is composed by one web project, one library project and one unit test project. When I open the solution and try to run th

Answer 1

For the Visual Studio 2013.5, clearing the \TestResults directory in the solution helped. Visual Studio corrupted the mdf file in which it stores the discovered tests, thus preventing the discovery of unit tests.