[Haskell-cafe] how do i use quickcheck in the IO monad?

[Don Stewart]

aeyakovenko:
> If i have functions in the IO monad, is there a way to use quickcheck
> to test them?  I have a bunch of C bindings that unfortunately are not
> "safe".  But i would like to be able to use QuickCheck to test them.
> 

Typically, via unsafePerformIO, and check the invariants that need to
hold for that to be safe by hand.

E.g.

prop_foo x = unsafePerformIO $ do
                writeFile "f" x
                y <- readFile "f"
                return (x == y)

-- Don