I have not been able to debug or step through unit test.
Here is my sample test code...
using System;
using System.Text;
using System.Collections.Gen
Maybe simply debugging tests and setting breakpoints works in some kinds of Unit tests but it doesn't if you debug e.g. Web service.
To debug a Web Service (break inside a Unit test) you have to insert this code:
System.Diagnostics.Debugger.Break();
This will show a popup saying the application stopped working and you can choose to debug it.
More here: http://msdn.microsoft.com/en-us/library/ms243172.aspx#DebuggingOnCassini