package qcheck-core

Changes

0.90 (2025-12-19)

• Remove deprecated function generators QCheck.{fun1_unsafe,fun2_unsafe}

• Renamed float generator combinators:

  • Add QCheck.Gen.{float_pos, float_neg} and deprecate QCheck.Gen.{pfloat, nfloat}
  • Add QCheck.{float_pos, float_neg} and deprecate QCheck.{pos_float, neg_float}
  • Add QCheck2.{float_pos, float_neg} and deprecate QCheck2.{pfloat, nfloat}
  • Add QCheck.(--.) as a synonym for QCheck.float_range for consistency
  • Add float_exp to QCheck.Gen, QCheck, and QCheck2.Gen and make the existing exponential binding a synonym for it

• Renamed char generator combinators:

  • Add QCheck.char_range for consistency
  • Add QCheck.{char_printable,printable} and deprecate QCheck.printable_char
  • Add QCheck.{char_numeral,numeral} and deprecate QCheck.numeral_char
  • Add QCheck.Gen.char_printable and make QCheck.Gen.printable an alias for it
  • Add QCheck.Gen.char_numeral and make QCheck.Gen.numeral an alias for it
  • Add QCheck2.char_printable and make QCheck2.printable an alias for it
  • Add QCheck2.char_numeral and make QCheck2.numeral an alias for it
• Deprecate QCheck.Gen.opt and QCheck2.Gen.opt for consistency

• Renamed bytes generator combinators:

  • Add QCheck.bytes_size for consistency
  • Deprecate QCheck.bytes_gen_of_size and QCheck.bytes_of_size
  • Removed optional gen parameter from QCheck.Gen.bytes for consistency (API breaking): To fix it, replace Gen.bytes ~gen:char_gen with Gen.bytes_of char_gen
  • Added QCheck.Gen.bytes_size_of, QCheck.bytes_size_of, and QCheck2.Gen.bytes_size_of for consistency

• Renamed string generator combinators:

  • Add QCheck.string_size for consistency
  • Removed optional gen parameter from QCheck.Gen.string for consistency (API breaking): To fix it, replace Gen.string ~gen:char_gen with Gen.string_of char_gen
  • Add QCheck.Gen.string_size_of, QCheck.string_size_of, and QCheck2.Gen.string_size_of for consistency
  • Deprecate QCheck.Gen.small_string, QCheck.small_string, and QCheck2.small_string
  • Deprecate QCheck.string_gen_of_size
  • Deprecate QCheck.string_gen
  • Deprecate QCheck.string_of_size
  • Deprecate QCheck.printable_string
  • Deprecate QCheck.printable_string_of_size
  • Deprecate QCheck.string_printable_of_size
  • Deprecate QCheck.small_printable_string
  • Deprecate QCheck.string_small_printable
  • Deprecate QCheck.numeral_string
  • Deprecate QCheck.string_numeral
  • Deprecate QCheck.numeral_string_of_size
  • Deprecate QCheck.string_numeral_of_size

• Renamed array generator combinators:

  • Add QCheck.Gen.array_small and deprecate QCheck.Gen.small_array
  • Add QCheck2.Gen.array_small and deprecate QCheck2.Gen.small_array
  • Add QCheck.array_small for consistency
  • Add QCheck.array_size and deprecate QCheck.array_of_size
  • Deprecate badly named QCheck.Gen.array_repeat and QCheck2.Gen.array_repeat

• Renamed list generator combinators:

  • Add QCheck.list_size and deprecate QCheck.list_of_size
  • Add QCheck.Gen.list_small and deprecate QCheck.Gen.small_list
  • Add QCheck.list_small and deprecate QCheck.small_list
  • Add QCheck2.Gen.list_small and deprecate QCheck2.Gen.small_list
  • Deprecate badly named QCheck.Gen.list_repeat and QCheck2.Gen.list_repeat

• Renamed int generator combinators:

  • Add QCheck.Gen.int_small and deprecate QCheck.Gen.small_signed_int
  • Add QCheck.int_small and deprecate QCheck.small_signed_int
  • Add QCheck2.Gen.int_small and deprecate QCheck2.Gen.small_signed_int
  • Add QCheck.Gen.int_pos and deprecate QCheck.Gen.pint
  • Add QCheck2.Gen.int_pos without optional origin and deprecate QCheck2.Gen.pint
  • Add uniformly distributed QCheck.Gen.int_neg and deprecate non-uniform QCheck.Gen.neg_int
  • Add uniformly distributed QCheck.int_neg and deprecate non-uniform QCheck.neg_int
  • Add uniformly distributed QCheck2.Gen.int_neg and deprecate non-uniform QCheck2.Gen.neg_int
  • Add QCheck.Gen.int_small_corners
  • Add QCheck.int_small_corners, expand QCheck.Gen.int_corners, and deprecate unsigned QCheck.small_int_corners
  • Add QCheck2.Gen.int_small_corners, expand QCheck2.Gen.int_corners, and deprecate (unsigned) QCheck2.Gen.small_int_corners
  • Deprecate unused QCheck.Gen.big_nat
  • Deprecate unused QCheck2.Gen.big_nat
  • Add missing QCheck.nat
  • Add QCheck.Gen.int_pos_small and alias QCheck.Gen.nat_small and deprecate QCheck.Gen.small_nat
  • Add QCheck.int_pos_small and alias QCheck.nat_small and deprecate QCheck2.Gen.small_nat
  • Add QCheck2.Gen.int_pos_small and alias QCheck2.Gen.nat_small and deprecate QCheck2.Gen.small_nat
  • Add QCheck.Gen.int_pos_mid alias for QCheck.Gen.nat
  • Add QCheck.int_pos_mid alias for QCheck.nat
  • Add QCheck2.Gen.int_pos_mid and alias QCheck2.Gen.nat_mid

• Renamed monadic and applicative generator combinators:

  • Add missing QCheck.Gen.bind for consistency
  • Add missing QCheck.Gen.ap for consistency

• Renamed flatten combinators:

  • Add QCheck.Gen.flatten_list and deprecate QCheck.Gen.flatten_l
  • Add QCheck.Gen.flatten_array and deprecate QCheck.Gen.flatten_a
  • Add QCheck.Gen.flatten_option and deprecate QCheck.Gen.flatten_opt
  • Add QCheck.Gen.flatten_result and deprecate QCheck.Gen.flatten_res
  • Add QCheck2.Gen.flatten_list and deprecate QCheck2.Gen.flatten_l
  • Add QCheck2.Gen.flatten_array and deprecate QCheck2.Gen.flatten_a
  • Add QCheck2.Gen.flatten_option and deprecate QCheck2.Gen.flatten_opt
  • Add QCheck2.Gen.flatten_result and deprecate QCheck2.Gen.flatten_res

• Renamed shuffle combinators:

  • Add QCheck.Gen.shuffle_array and deprecate in-place QCheck.Gen_shuffle_a
  • Add QCheck.Gen.shuffle_list and deprecate QCheck.Gen_shuffle_l
  • Add QCheck.Gen.shuffle_list_weighted and deprecate QCheck.Gen_shuffle_w_l
  • Add QCheck2.Gen.shuffle_array and deprecate QCheck2.Gen_shuffle_a
  • Add QCheck2.Gen.shuffle_list and deprecate QCheck2.Gen_shuffle_l
  • Add QCheck2.Gen.shuffle_list_weighted and deprecate QCheck2.Gen_shuffle_w_l

• Renamed oneof combinators:

  • Add QCheck.Gen.oneof_list and deprecate QCheck.Gen.oneofl
  • Add QCheck.Gen.oneof_array and deprecate QCheck.Gen.oneofa
  • Add QCheck.oneof_list and deprecate QCheck.oneofl
  • Add QCheck.oneof_array and deprecate QCheck.oneofa
  • Un-deprecate QCheck.oneof with a better specification and optional parameters like QCheck.oneof_weighted and deprecate QCheck.choose for consistency
  • Add QCheck2.Gen.oneof_list and deprecate QCheck2.Gen.oneofl
  • Add QCheck2.Gen.oneof_array and deprecate QCheck2.Gen.oneofa

• Renamed frequency combinators:

  • Add QCheck.Gen.oneof_weighted and deprecate QCheck.Gen.frequency
  • Add QCheck.Gen.oneof_list_weighted and deprecate QCheck.Gen.frequencyl
  • Add QCheck.Gen.oneof_array_weighted and deprecate QCheck.Gen.frequencya
  • Add QCheck.oneof_weighted and deprecate QCheck.frequency
  • Add QCheck.oneof_list_weighted and deprecate QCheck.frequency_list
  • Add QCheck.oneof_array_weighted and deprecate QCheck.frequency_array
  • Add QCheck2.Gen.oneof_weighted and deprecate QCheck2.Gen.frequency
  • Add QCheck2.Gen.oneof_list_weighted and deprecate QCheck2.Gen.frequencyl
  • Add QCheck2.Gen.oneof_array_weighted and deprecate QCheck2.Gen.frequencya
• Add missing QCheck2.Gen.map_keep_input for consistency
• Add QCheck.no_shrink for consistency
• Fix shrinking for QCheck2.Gen.exponential which could shrink to infinity
• Remove deprecation annotations for QCheck.Test.{get,set}* helpers
• Remove deprecation annotation for QCheck2.Gen.add_shrink_invariant

• Renamed corners bindings

  • Deprecate QCheck.Gen.int_corners and QCheck.Gen.int_pos_corners
  • Deprecate QCheck2.Gen.int_corners and QCheck2.Gen.int_pos_corners

0.27 (2025-10-31)

• 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 "-nan" also on Windows and macOS, and correct documentation for QCheck.{float,pos_float,neg_float} in that they may produce nans since #350 from 0.26
• Eta-expand a couple of partial application to compile under OxCaml

0.26 (2025-07-25)

• 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 QCheck/QCheck2 situation in 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

0.25 (2025-04-05)

• 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
• [ppx_deriving_qcheck] Support ppxlib.0.36.0 based on the OCaml 5.2 AST

0.24 (2025-02-17)

• [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

0.23 (2024-12-12)

• Quote and escape in Print.string and Print.char in the QCheck module, mirroring the QCheck2.Print module's behaviour. Also quote and escape Print.bytes in both QCheck and QCheck2.
• Clean-up QCheck and QCheck2 documentation pages
• Add exponential generator to QCheck, QCheck.Gen, and QCheck2.Gen
• Add Shrink.bool and use it in QCheck.bool
• Remove unread fun_gen field from QCheck2's fun_repr_tbl type thereby silencing a compiler warning

0.22 (2024-07-05)

• Remove QCheck2.TestResult.get_instances as retaining previous test inputs cause memory leaks
• Make QCheck2.state.res immutable, silencing a compilation warning

0.21.3 (2023-11-30)

• Drop the dependency on base-bytes as it is provided in all supported versions of the OCaml compiler

0.21.2 (2023-08-25)

• Reintroduce the Shrink.list_spine fix by catching Invalid_argument and falling back on an address comparison.
• Fix #273 by lowering ppx_deriving_qcheck's qcheck dependency to qcheck-core

0.21.1 (2023-05-19)

• Roll back the Shrink.list_spine fix, as it was utilizing polymorphic equality that can raise an exception on function comparison.

0.21 (2023-05-08)

• make Test.check_result, Test.check_cell_exn, and Test.check_exn honor test polarity by raising Test_unexpected_success when a negative test (expected to have a counter example), unexpectedly succeeds.
• fix issue with ppx_deriving_qcheck deriving a generator with unbound gen for recursive types #269 and a related issue when deriving a generator for a record type
• fix #241 causing QCheck.Shrink.int* to emit duplicates, also affecting QCheck.Shrink.{char,string}
• fix a cornercase where Shrink.list_spine would emit duplicates

0.20 (2022-11-07)

• add several new bytes combinators:

  • {QCheck,QCheck2}.Gen.{bytes_size,bytes,bytes_of,bytes_printable,bytes_small,bytes_small_of}
  • QCheck.{Print,Shrink,Observable}.bytes
  • QCheck2.{Print,Shrink}.bytes
  • QCheck.{bytes_gen_of_size,bytes_of,bytes,bytes_small,bytes_small_of,bytes_of_size,bytes_printable}

• add new string combinators and aliases:

  • {QCheck,QCheck2}.Gen.{string_small,string_small_of}
  • QCheck.{string_small,string_small_of,string_of,string_printable,string_printable_of_size,string_small_printable,string_numeral,string_numeral_of_size}
• (QCheck2.small_string character generator argument is no more optional - reverted again due to backwards incompatibility)
• add an optional argument with conservative default to Shrink.string
• fix shrinkers in QCheck.{printable_string,printable_string_of_size,small_printable_string,numeral_string,numeral_string_of_size} #257
• add QCheck2.Gen.set_shrink to modify the generator's shrinker
• add QCheck2.Gen.no_shrink to build a generator with no shrinking
• add an environment variable QCHECK_MSG_INTERVAL to control QCheck_base_runner.time_between_msg
• fix unknown option error message referring to qtest

0.19.1 (2022-07-13)

• fix: allow ~count in Test.make to be 0
• fix: allow ~long_factor in Test.make to be 0

0.19 (2022-07-08)

• use Float.equal for comparing floats in the Observable module underlying function generators.
• add optional debug_shrink parameters in alcotest interface and expose default debug_shrinking_choices in test runners
• add missing ?handler parameter to Test.check_cell_exn
• remove --no-buffer option on dune runtest to avoid garbling the test output
• add an option retries parameter to Test.make et al. for checking a property repeatedly while shrinking. This can be useful when testing non-deterministic code. #212
• add tup2 to tup9 for generators
• add Test.make_neg for negative property-based tests, that are expected not to satisfy the tested property.
• rename Gen.opt to Gen.option but keep the old binding for compatibility.
• add additional expect and unit tests and refactor expect test suite
• fix function generation affecting reproducability #236
• add a shrinker performance benchmark #177
• fix distribution of QCheck2.printable which would omit certain characters

• shrinker changes

  • recursive list shrinker with better complexity
  • string shrinker reuses improved list shrinker and adds char shrinking
  • function shrinker now shrinks default entry first and benefits from list shrinker improvements
  • replacing the linear-time char shrinker with a faster one reusing the bisecting int shrinker algorithm
  • add Shrink.char_numeral and Shrink.char_printable
  • add shrinking for char arbitrarys char, printable_char, and numeral_char

• documentation updates:

  • clarify upper bound inclusion in Gen.int_bound and Gen.int_range
  • clarify printable_char and Gen.printable distributions
  • add missing string_gen_of_size and small_printable_string documentation
  • document QCheck_alcotest.to_alcotest
  • fix documented size distribution for arbitrary generators string_gen, string, printable_string, numeral_string, list, and array
  • fix exception documentation for check_result, check_cell_exn, and check_exn
  • fix documentation for the distribution of Gen.printable and printable_char
  • fix documentation for the shrinking behaviour of QCheck2.printable
• add environment variable QCHECK_LONG_FACTOR similar to QCHECK_COUNT #220
• make test suite run on 32-bit architectures

0.18.1 (2022-02-03)

• fix Gen.{nat,pos}_split{2,}
• fix stack overflow in #156

0.18 (2021-09-03)

This releases marks the addition of QCheck2, a module where generation and shrinking are better integrated. See #109 and #116.

This API is still experimental. The normal QCheck module is still there and hasn't changed much.

deprecations and breakges:

• make QCheck.Test_result.t abstract and add missing getters
• deprecate QCheck.oneof
• deprecate Gen.string_readable in favor of Gen.(string_of char) or the new Gen.string_printable
• require at least OCaml 4.08

other changes:

• unsigned int32 and int64
• rename small_int_corners
• add ?ratio to opt, to modify random distribution of options

0.17 (2021-02-15)

• new function: Gen.delay
• install printer for an internal exception
• fix(runner): use random state independently for each test
• Fixes distribution and min_int issues
• doc: point to @jmid 's website

0.16 (2020-11-04)

• fix(runner): detect more failures in the runner
• fix: catch exceptions in generators and log them. (#99)
• test: add test for #99
• fix doc

0.15 (2020-09-06)

• fix: in main runner, remove reset line in more places if colors=false
• fix: invalid arg in int_range when a<0
• fix(runner): do not use ansi code for random seed if colors=false
• feat: on >=4.08, provide let operators

0.14 (2020-07-30)

• modify int_range to make it accept ranges bigger than max_int.
• less newline-verbose stats
• add int{32,64} shrinkers to arbitrary gens
• add int{32,int64} shrinkers
• move to ounit2 for QCheck_ounit

0.13 (2020-01-24)

• make counter private
• Add debug shrinking log
• fix: small fix related to stdlib/pervasives
• feat: add flatten combinators in gen

0.12 (2019-11-08)

• fix singleton list shrinking
• feat: add Gen.char_range and Gen.(<$>) (credit @spewspews)

0.11 (2019-10-02)

• Add QCheck.Gen.{string_of,string_readable}
• fix int_bound bound inclusiveness problem
• change implementation of int_bound to generate values using Random.State.int for bound < 2^30
• add weighted shuffled lists generator
• add float_range to generate a floating-point number in the given range (inclusive)
• add float_bound_inclusive and float_bound_exclusive to generate floating-point numbers between 0 and a given bound

0.10 (2019-07-15)

• Shrink: decompose Shrink.list into Shrink.list_spine and Shrink.list_elems
• Gen.fix has a more general and useful type
• update README to include Rely section (qcheck now available for reason-native!)
• Fix stat printing
• speed-up list shrinker
• Better int shrinking
• core: modify proba distributions again, add big_nat
• feat: add small_array, modify distributions
• print number of warnings in runner's summary
• refactor: modify type of results to make them more accurate
• feat: warn/fail if too many tests passed only b/c precondition failed

0.9 (2018-09-18)

• add qcheck-ounit sublibrary
• use environment variables to configure qcheck-alcotest tests
• alcotest backend for qcheck
• make qcheck.ounit tests verbose by default
• make qcheck is a compatibility library, depends on qcheck-core
• split lib into qcheck and qcheck.ounit
• add TestResult.is_success helper
• give access to list of instances in test results
• allow setting time_between_msg in runner
• chore: remove submodule
• chore: add travis support
• doc: explanations about qcheck.ounit runners
• doc: update readme

0.8 (2018-02-03)

• migrate to jbuilder
• fix warnings
• add some useful functions
• update oasis files (close #48)
• update copyright header (closes #47)

0.7 (2017-08-21)

• switch to BSD license, make it more explicit (close #43)
• improve multi-line message printing in ounit (closes #46)
• fix complexity of add_stat
• allow negative entries in statistics (see #40)
• add a way for tests to report messages to the user (see #39)
• add QCheck.Shrink.int_aggressive and make default int shrinker faster
• shrinker for map_keep_input
• add QCheck.set_gen, missing for some reason
• more compact verbose output (see #33)
• better handling of dynamic progress line
• Add colors to checkmarks in verbose mode
• improve statistics display for runner
• recover exception of shrunk input
• print status line before the solving starts

0.6 (2017-05-29)

• add find_example and find_example_gen to synthesize values from properties (see #31)
• add QCheck.gen for accessing the random generator easily
• colorful runners, with --no-colors to disable them
• add more generator (for corner cases)
• better generation of random functions (see #8), using Observable and an efficient internal representation using heterogeneous tuples, printing, and shrinking. deprecate old hacks.
• add statistics gathering and display (see #30)
• better printing of Tuple
• improve Shrink.{array,list} (see #32)
• Change asserts to raise Invalid_arg (following the doc), and update doc
• Change Gen.{int_bount,int_range} to support up to 2^62

0.5.3.1 (2017-01-27)

• fix regression in runner output (print results of collect)
• update the @since tags

0.5.3 (2017-01-25)

• missing char in Gen.char (close #23)
• add test and doc to opam
• add small_list generator
• add ~long_factor to tests and runner, for long tests
• add more examples in readme, better doc for runners
• improved reporting when running qcheck tests
• add Test.get_count on test cells

0.5.2 (2017-01-11)

• Add cli option for backtraces in QCheck_runner
• Add test case for raising exception
• Better handling of backtraces
• All tests now have a name
• Add step function called on each instance in a test
• make small_int a deprecated alias to small_nat
• add small_signed_int
• remove some warnings
• use safe-string, and fix related bug
• Add long tests options to QCheck_runner
• Add length specification for to_ounit2_test
• Added paragraph in README about long tests

0.5.1 (2017-01-08)

• document exceptions
• add small_nat, change small_int semantics (close #10)
• add QCheck.assume_fail
• add QCheck.assume; explain preconditions a bit (close #9)
• Polish documentation
• Added quad support uniformly

0.5 (2016-12-16)

• merge back from qtest: big changes in API, shrinking, use 'a arbitrary type that combines printer, generator, shrinker, etc. (see git log)
• merlin file
• reorganize sources, _oasis, .merlin, etc.

0.4 (2015-06-09)

• bugfix in fix_fuel
• if verbose enabled, print each test case
• add QCheck.run_main
• QCheck_ounit.~::
• add (>:::)
• add qcheck_ounit ml{lib,dylib}
• trivial ounit integration
• make test_cell.name optional
• Arbitrary.fix_fuel(_gen): add a recursive case
• Arbitrary.fix_fuel_gen, similar to fix_fuel but threading a state bottom-up to make choices depend on the path
• Arbitrary.fail_fix to fail in a fixpoint
• helper cases for Arbitrary.fix_fuel

0.3 (2014-11-14)

• get rid of submodule generator
• Arbitrary.fix_fuel, to generate complex recursive structures
• new combinators (infix map, applicative funs, shuffle)
• remove generator/Generator, and a deprecation warning
• output of printers of lists/arrays now parsable by ocaml toplevel

0.2 (2013-11-07)

• integrate Gabriel Scherer's Generator into QCheck
• add |||
• add Prop.raises
• print the faulty instance in case of error (if a printer is available)
• some combinators for QCheck.Arbitrary
• QCheck.mk_test takes more arguments

0.1 (2013-10-06)

• oasis based build system
• source files