I\'m testing a class that is part of a hierarchy. I\'ve been setting up my test classes with the object under test, and a PrivateObject to allow access to that
As André Pena wrote. Why would you like to test private members of the Baseclass through the Subclass. You wouldn't have access to these members in normal code of your Subclass either. You have to make the Properties members protected to have access to them from the Subclass.
Then you can also test these Members with the PrivateObject.