[Haskell-beginners] HUnit - testing for failed pattern match

Hello, Given the following contrived function: giveMeThree x | x == 3 = True How do I test with HUnit that 2 is invalid input? giveMeThreeTests = [ "Likes 3" ~: True ~=? giveMeThree 3 , "Dislikes 2" ~: ..... -- what? ] I couldn't find anything mentioned in the HUnit user guide. References to appropriate documentation appreciated. Cheers, Xavier