PropEr vs Racket QuickCheck

PropEr is a free, open-source testing tool for Erlang programs. It performs automated, semi-random property-based testing and can generate input data from Erlang type declarations. Functions can be tested automatically from information in their Erlang specifications, while properties are written as Erlang expressions with predefined macros. PropEr also supports model-based random testing for stateful systems and targeted property-based testing using search-based techniques. Failing cases can be shrunk, and the project supports EUnit and Common Test. Constraints that Erlang’s type language cannot express can be handled with custom generators; filtering may keep trying random values until one passes. The generator language differs from Erlang’s type language for list expressions, including support for particular list lengths and element types. PropEr is self-hosted, supports Erlang, and is distributed under GPL version 3 or later. The guide describes installation from GitHub source, with make, or through Homebrew.

Racket QuickCheck is a free package for checking program properties with generated inputs. A property is written as ordinary Racket code, and the package runs it against generated values; if a check fails, it reports a counterexample and the arguments that produced it. Its default configuration runs 100 successful tests, and helpers allow counts of 1,000, 10,000, or a custom number. Built-in generators cover integers, real numbers, characters, lists, vectors, strings, and symbols, and custom generators are supported. The `rackunit/quickcheck` integration raises a RackUnit exception when a check fails and includes the test count and counterexample arguments. Install the package with `raco pkg install quickcheck` or through DrRacket’s GUI package manager. It requires Racket v6.0 or newer. Racket provides installers for Linux, macOS, and Windows. The package listing reports a successful build and passing tests, while also noting missing license metadata. The listed price is free.