The class published in the post is the V1 implementation of this idea. It has been upgraded to AOP testing, using PostSharp's Composition Aspect, so in fact, you don't have to inherit any TypeTest class or anything, only mark your test class with an attribute describing what test you want it to run.
I kinda like the mirroring of test attributes, against real-code attributes that we are actually testing.
Do you have any other ideas of tests that can be implemented that way?