Racket QuickCheck vs Rapid

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.

Rapid has no write-up on Specifiction yet; its figures are above.