0.19

This release brings a range of new features and improvements, detailed below.

• new features and feature extensions

  • 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
  • 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.
  • add environment variable QCHECK_LONG_FACTOR similar to QCHECK_COUNT #220
  • rename Gen.opt to Gen.option but keep the old binding for compatibility.
  • 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

• bug fixes

  • fix function generation affecting reproducability #236
  • fix distribution of QCheck2.printable which would omit certain characters
  • use Float.equal for comparing floats in the Observable module underlying function generators.

• 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

• internal and test suite changes

  • add additional expect and unit tests and refactor expect test suite
  • add a shrinker performance benchmark #177
  • remove --no-buffer option on dune runtest to avoid garbling the test output
  • make test suite run on 32-bit architectures