proptest

Proptest is a property testing framework for Rust, in the QuickCheck family and inspired by the Hypothesis framework for Python. It tests that certain properties of the code hold for arbitrary inputs, and when a failure is found, it automatically finds the minimal test case that reproduces the problem.

Unlike QuickCheck, generation and shrinking are defined per value through strategies rather than per type, which makes them more flexible and simplifies composition. Tests are written with the proptest! macro alongside regular Rust tests, and failing cases are saved so that they are replayed in later runs. A book provides a detailed introduction.

Proptest is free and open source under the Apache 2.0 or MIT licence. The crate is close to feature-complete and mainly sees passive maintenance.