Automated test for links between models

Hey, I've got plenty of models that are interconnected by methods:

belongs_to has_many has_one and :through

I've created all of the models first, and now I have the headache to test that all of the links work properly. I've been wondering if there's any gem or plugin that would do it automatically? By just specifying the links with some meta language and than it would automatically build all the tests? Any suggestions?

Cheers,

michau