This is QuickCheck 2, a library for random testing of program properties.

Add QuickCheck to your package dependencies to use it in tests or REPL.

The quickcheck-instances 1 companion package provides instances for types in Haskell Platform packages at the cost of additional dependencies.

The make-hugs script makes a Hugs-compatible version of QuickCheck. It may also be useful for other non-GHC implementations.