check-it is a randomized specification-based test generation tool (à la Haskell's QuickCheck) designed to be used from within other test frameworks. Its flexible value-generation facility can also be used on its own outside of a testing context.


  • Shrinks values to discover a minimum failing case
  • Can be tuned to manage the size of data structures generated from recursive type specifications
  • Can be configured to save previously discovered random failures as deterministic regression tests in future runs of the test suite