More example.

[Moondee]

Could you provide more concrete examples on feature, probably some challenging cases that gentest could catch?

[graue]

I'd like to at some point, yes.

In the meantime, @eventualbuddha wrote up a nice example here using a pow() function. (The example uses a small wrapper Brian wrote around gentest to run the tests; something similar will soon be built into gentest itself.)

I would also recommend the talk Testing the Hard Stuff and Staying Sane by John Hughes, one of the inventors of the original QuickCheck, and Powerful Testing with test.check by Reid Draper, about the Clojure test.check library that gentest is heavily influenced by and works similarly to. While not about gentest specifically, these talks may give you some inspiration on what kind of tests you can write.