This brings to mind a conversation that I've had several times over the years. It goes something like this:

> Wouldn't it be cool if we could have code that would test itself?

> Yeah, if only there were some kind of automated way to encapsulate the requirements of classes and methods that could ensure that they behaved within some known boundaries...?

We've had automated unit tests for quite some time, but they are more often called compiler checks. Want your "automated unit tests" to be more comprehensive? Improve your type system and your compiler!

With all that said, I do not want to be dismissive of peoples' projects. This is fun and neat.