A property-based testing library

Version on this page:1.1.1@rev:1
LTS Haskell 18.0:1.2.1
Stackage Nightly 2021-06-21:1.2.1
Latest on Hackage:1.2.1

See all snapshots smallcheck appears in

BSD-3-Clause licensed by Colin Runciman, Roman Cheplyaka
Maintained by Roman Cheplyaka
This version can be pinned in stack with:smallcheck-1.1.1@sha256:b19c841b12cc34f6379c2b72bc4c250da9b0346c46690dae419caaa0310478fa,1135

Module documentation for 1.1.1

SmallCheck: a property-based testing library for Haskell

SmallCheck is a testing library that allows to verify properties for all test cases up to some depth. The test cases are generated automatically by SmallCheck.

Usefulness of such an approach to testing is based on the following observation:

If a program fails to meet its specification in some cases, it almost always fails in some simple case.

To get started with SmallCheck:



Version 1.1.1

Export some auxiliary functions from T.S.Series, and document how to express consN and altsN for N > 4.


Documentation fixes

Version 1.1

  • Add a Serial instance for Ratio
  • Add the NonEmpty wrapper for lists
  • Add listM (the monadic version of list)
  • Add optional explanation for test outcomes

Version 1.0.4

Fix compatibility with GHC 7.4.1

Version 1.0.3

Fix a bug where no test cases were generated for some functional types (#19).

Version 1.0.2

Fix a bug in the generic instance

Version 1.0.1

Make SmallCheck build with GHC 7.4

Version 1.0

This is a major incompatible release of SmallCheck. Virtually every function has changed its name, type, semantics or module. So please carefully read the docs when upgrading.

For some highlights, see this blog post.

Version 0.6.2

  • Derive Typeable Property instance
  • Add smallCheckPure

Version 0.6.1

  • Documentation improvements
  • Make the package build with GHC 7.4.1

Version 0.6

  • Default Generic implementation of Serial instance (by Bas van Dijk)
  • The code is split into modules
  • Convert much of README into haddock documentation
  • Many small API changes
  • Remove impure Testable (IO a) instance

Version 0.5

Make the package build with GHC 7.2. Some cosmetic changes.

Version 0.4

The module SmallCheck is now Test.SmallCheck. Packaged with Cabal.

Version 0.3

Existential quantifiers now have unique variants for which two witnesses are reported when uniqueness fails. The over-generating coseries method for functions of functional arguments has been replaced; now ‘coseries’ and the ‘alts’ family take a series argument. Test counters are now Integers, not Ints. Ord and Eq are now derived for the N types. Examples extended.

Version 0.2

The ‘smallCheck’ driver now takes an argument d and runs test series at depths 0..d without interaction, stopping if any test fails. The interactive variant is still available as ‘smallCheckI’. All Prelude numeric types now have Serial instances, including floating-point types. Serial types Nat and Natural are also defined. Examples extended.

Version 0.1

The differences from 0.0 are two fixes (space-fault, output buffering), an ‘unsafe’ but sometimes useful Testable (IO a) instance and additional examples.