This is an excellent update to the suite, and includes all the files necessary to test your own provider.
"This suite is used to test the CodeDom within the .NET Framework team. The CodeDom test suite is a collection of tests that enables writers of custom code providers a way to verify that they are generating and compiling code from their provider properly. Each test takes a pre-built CodeDom tree and generates and compiles the tree using the provider supplied to it on the command line. The tests then verify the assembly generated from the code provider through reflection. Also provided next to each CodeDom tree as source code comments is the generated C# code from that tree. This will be useful for those wanting to see what CodeDom constructs match up with which C# constructs.
The test suite has been updated to include the testing of Whidbey CodeDom features, test case extensibility, an improved interface, and source code comments."