[ekidd]

That's weird, because Haskell has great unit testing tools. I'm especially fond of QuickCheck, which allows me to define algebraic properties of functions:

xs == reverse (reverse xs)

QuickCheck will generate hundreds of random lists and make sure that the property holds. This can be enormously useful in smoking out odd problems in complex functional code.

For simpler testing scenarios, HUnit is OK, although it sometimes feels a bit clunky.