CsCheck vs QCheck

CsCheck is a free C# random testing library inspired by QuickCheck, intended for self-hosted use. Its composable Gen classes shrink generated cases automatically without Arb classes, and a shrunk case includes a seed that can reproduce a failure. The library supports random, model-based, metamorphic, performance, specification, regression, parallel and equality testing. Parallel tests compare outcomes with possible linearizations and support shrinking. Specification checks can enumerate reachable state spaces exhaustively or sample them, and can test whether declared faults are caught. Its Faster function statistically compares methods to assess whether one is faster and can run as a normal test across platforms. Example tests use TUnit, though the project says CsCheck can be used with any testing framework. The project page reports more than 1,000 F# tests using CsCheck in MKL.NET. NuGet lists version 4.9.1 and installation instructions for the .NET CLI and PackageReference. The project notes that generic recursion limits AOT compatibility; its Dbg module is temporary and may change between minor versions.

QCheck is a property-based testing library for OCaml, inspired by QuickCheck. Rather than relying only on hand-picked examples, it provides combinators to generate values such as lists, arrays, tuples, recursive types, and algebraic types for checking properties. When a check fails, generators can be paired with printers and shrinkers to show and reduce counterexamples. QCheck2 builds shrinking into its generators, though the project describes that API as less battle-tested than QCheck. The package family includes qcheck-core, qcheck-ounit, qcheck-alcotest, qcheck, and ppx_deriving_qcheck; the last can derive generators from type declarations. Runner options include QCheck_base_runner in qcheck-core and QCheck_runner with OUnit compatibility in qcheck, with integration layers for OUnit and Alcotest. The project also points to qcheck-stm for sequential and parallel model-based tests and qcheck-lin for sequential consistency testing. Installation is available through opam, and the source can be built with make. The minimal qcheck-core package depends only on unix and dune. QCheck is free and licensed under BSD-2-Clause.