# \[ANN\] QCheck 0.24 **URL:** \ **Category:** Community\ **Tags:** qcheck, testing, announce\ **Created:** [February 27, 2025, 6:37pm UTC](https://discuss.ocaml.org/t/ann-qcheck-0-24/16198 "2025-02-27T18:37:14Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![jmid](https://avatars.discourse-cdn.com/v4/letter/j/eada6e/32.png) [@jmid](https://discuss.ocaml.org/u/jmid)\ **Post date:** [February 27, 2025, 6:37pm UTC](https://discuss.ocaml.org/t/ann-qcheck-0-24/16198/1 "2025-02-27T18:37:14Z")
I’m happy to announce the 0.24 release of `qcheck`, `qcheck-core`, `qcheck-alcotest`, and `qcheck-ounit`, along with a 0.6 release of `ppx_deriving_qcheck` πŸŽ‰ `QCheck` is a library for randomized property-based testing, inspired by Haskell’s seminal QuickCheck library. The 0.24 release contains a range of improvements to the integrated shrinking of `QCheck2`, initially introduced in the 0.18 release. As a consequence, its shrinking algorithms should act more predictably, reduce faster, and report smaller counterexamples. In essence, the 0.24 release is what we hoped 0.18 would be. The release also adds missing `result`, `int32`, and `int64` combinators, as well as more documentation. If you’ve previously given `QCheck2`’s integrated shrinking a spin, I encourage you to try it again with the patched 0.24 release. For new users, the 0.24 release is also a good candidate to check out! πŸ˜ƒ Please share any problems you encounter on the `qcheck` repo: [GitHub - c-cube/qcheck: QuickCheck inspired property-based testing for OCaml.](https://github.com/c-cube/qcheck) Full change log: - [qcheck-alcotest] Add an optional `speed_level` parameter to `to_alcotest` - Adjust the `QCheck2.Gen.list` shrinker to produce minimal counterexamples at size 3 too - Replace the `QCheck2` OCaml 4 `Random.State.split` hack with a faster one - Improve the `QCheck2.Gen.list` shrinker heuristic and utilize the improved shrinker in other `QCheck2` `{list,array,bytes,string,function}*` shrinkers - Use `split` and `copy` in `Random.State` underlying `QCheck2` to avoid non-deterministic shrinking behaviour - Add missing documentation strings for `QCheck.{Print,Iter,Shrink,Gen}` and `QCheck2.Gen`. - Add `result` combinators to `QCheck`, `QCheck.{Gen,Print,Shrink,Observable}`, and `QCheck2.{Gen,Print,Observable}`. - Add missing combinators `QCheck{,2}.Print.int{32,64}`, `QCheck.Gen.int{32,64}`, `QCheck{,2}.Observable.int{32,64}`, and deprecate `QCheck.Gen.{ui32,ui64}` - Document `dune` usage in README Happy testing! πŸ˜ƒ ⌨ ---
**Author:** ![jmid](https://avatars.discourse-cdn.com/v4/letter/j/eada6e/32.png) [@jmid](https://discuss.ocaml.org/u/jmid)\ **Post date:** [April 7, 2025, 10:40am UTC](https://discuss.ocaml.org/t/ann-qcheck-0-24/16198/2 "2025-04-07T10:40:48Z")
FYI, QCheck 0.25 is now available from the opam repository πŸ˜ƒ > **[Releases Β· c-cube/qcheck](https://github.com/c-cube/qcheck/releases/)** > > QuickCheck inspired property-based testing for OCaml. - c-cube/qcheck The 0.25 release contains a combination of all-round fixes, documentation, and polishing: - Restore `Test.make`’s `max_fail` parameter which was accidentally broken in 0.18 - Adjust `stats` computation of average and standard deviation to limit precision loss, print both using scientific notation, and workaround MinGW float printing to also pass expect tests - Fix dune snippets missing a language specifier in README.adoc causing `asciidoc` to error - Add a note to `QCheck{,2.Gen}.small_int_corners` and `QCheck{,2}.Gen.graft_corners` about internal state, and fix a range of documentation reference warnings - Reorganize and polish the `README`, rewrite it to use `qcheck-core`, and add a `QCheck2` integrated shrinking example - Document `QCHECK_MSG_INTERVAL` introduced in 0.20 - Add `QCheck{,2}.Gen.map{4,5}` combinators The accompanying `ppx_deriving_qcheck.0.7` release offers: - Support `ppxlib.0.36.0` based on the OCaml 5.2 AST Thanks to @Pat-Lafon and @patricoferris for contributing PRs! πŸŽ‰ Happy testing! πŸ˜ƒ ⌨ ---
**Author:** ![jmid](https://avatars.discourse-cdn.com/v4/letter/j/eada6e/32.png) [@jmid](https://discuss.ocaml.org/u/jmid)\ **Post date:** [July 12, 2025, 9:07am UTC](https://discuss.ocaml.org/t/ann-qcheck-0-24/16198/3 "2025-07-12T09:07:29Z")
QCheck 0.26 is now available from your favorite opam repository! πŸŽ‰ > **[Releases Β· c-cube/qcheck](https://github.com/c-cube/qcheck/releases)** > > QuickCheck inspired property-based testing for OCaml. - c-cube/qcheck The 0.26 release adjusts the `QCheck` and `QCheck2` `float` generator distributions, which was previously confined to a subset of floating point numbers. Users may experience that existing tests known to pass start to fail with the new and broader distribution. In addition the release contains a number of other fixes and documentation improvements, incl. the removal of an annoying newline which would cause the test suite to fail on OCaml 5.4.0: - Align printed `collect` statistics and also add a percentage - Fix `QCheck{,2}.Gen.float` generator which would only generate numbers with an exponent between 2^{-21} and 2^{22} - Elaborate on the `QCheck`/`QCheck2` situation in the README - Add a missing `description` field to the \*.opam files - Document `Shrink` invariants in the `QCheck` module - Fix a `qcheck-ounit` test suite failure on OCaml 5.4, removing a needless extra newline - Fix `QCheck2` `float_range` operator which would fail on negative bounds - Fix `QCHECK_MSG_INTERVAL` not being applied to the first in-progress message Thanks to @Pat-Lafon, @rmonat, and @kit-ty-kate for contributing! πŸ™ ---
**Author:** ![jmid](https://avatars.discourse-cdn.com/v4/letter/j/eada6e/32.png) [@jmid](https://discuss.ocaml.org/u/jmid)\ **Post date:** [November 3, 2025, 4:08pm UTC](https://discuss.ocaml.org/t/ann-qcheck-0-24/16198/4 "2025-11-03T16:08:10Z")
QCheck 0.27 is now available from the opam repository πŸ₯³ > **[Release 0.27 Β· c-cube/qcheck](https://github.com/c-cube/qcheck/releases/tag/v0.27)** > > The 0.27 release is focused on improving the float shrinking support and also contains a small patch to make the package compile with OxCaml: > > Add QCheck.Shrink.float and enable shrinking for QChec... The 0.27 release is focused on improving the `float` shrinking support and also contains a small patch to make the package compile with OxCaml: - Add `QCheck.Shrink.float` and enable shrinking for `QCheck.float` - Add `QCheck.Shrink.float_bound` and enable shrinking for `QCheck.float_bound_inclusive` and `QCheck.float_bound_exclusive` - Add `QCheck.Shrink.float_range` and enable shrinking for `QCheck.float_range` - Enable shrinking for `QCheck.{pos_float,neg_float,exponential}` - Patch `QCheck.Print.float` and `QCheck2.Print.float` to print negative nans consistently as β€œ-nan” also on Windows and macOS, and correct documentation for `QCheck.{float,pos_float,neg_float}` in that they may produce `nan`s since #350 from 0.26 - Eta-expand a couple of partial application to compile under OxCaml Happy testing! πŸ˜ƒ