In a specific project, all of the tests can be executed successfully from Visual Studio. In Test Studio Standalone there are 4 tests deep in a hierarchy of folders that during test execution fail with the following message. For some reason building the DLL misses their code-behind.

System.ArgumentException: Unable to find the test class type 'MyNamespace.MyClass' in your test assembly. Please make sure your test code behind is compiled with your latest changes.   at ArtOfTest.WebAii.Design.Execution.ExecutionUtils.EnsureTypeExists(Assembly assm, String typeName)   at ArtOfTest.WebAii.Design.Execution.ExecutionUtils.CreateCodedTestInstance(Test test, TestResult result, String binariesFolder)   at ArtOfTest.WebAii.Design.Execution.ExecutionEngine.InternalExecuteTest(Test test, TestResult initializationResult)   at ArtOfTest.WebAii.Design.Execution.TestExecuteProxy.ExecuteTest(ExecuteTestCommand command)

In order to workaround this issue, you need to move these test files in a parent folder.