Koen Claessen and John Hughes

QuickCheck is a tool for testing Haskell programs automatically. The programmer provides a specification of the program, in the form of properties which functions should satisfy, and QuickCheck then tests that the properties hold in a large number of randomly generated cases. Specifications are expressed in Haskell, using combinators defined in the QuickCheck library. QuickCheck provides combinators to define properties, observe the distribution of test data, and define test data generators.

Resources

• Our paper from ICFP 2000.
• A new paper (presented at the Haskell Workshop 2002) on testing monadic programs, especially in the ST monad.
• An online manual.
• Module QuickCheck (distributed with Hugs and GHC).
• Module ShowFunctions, required with newer versions of Hugs (distributed with GHC).
• quickCheck, a program to invoke quickCheck for all properties in a module (this version invokes ghci, but is easily modified to run hugs instead).
• A warning on problems with random number generation under old versions of Hugs.
• QuickCheckM, which extends QuickCheck with monadic property combinators. This module uses the ST monad, so is not pure Haskell 98. It is the version which our Haskell workshop paper describes.

User Experiences

• Read Tom Moertel's entertaining story about his ICFP Programming Contest entry, including his experiences with QuickCheck.

Current Developments

Other Languages