If you add the [TestMethod] attribute to methods in a regular class library, they won't show up in the test view or test editor.  You may see a message "no tests are loaded."  This happens because Visual Studio doesn't look for the attribute in projects that don't have special "I am a test" markings.  If you create a test project from scratch and add the code the problem will go away, but if you've spent time customizing a project, its references, etc., fear not; you don't need to start over.  Edit the .csproj (or .vbproj) file manually and add the following XML as a child of the first <PropertyGroup> element that appears: