QuickTheories vs Scala Hedgehog

QuickTheories is a free, open-source property-based testing library for Java 8. It checks general properties and invariants by generating random valid inputs, then automatically searches for smaller or simpler values that still fail a property. The library reports the seed for a falsified property, and tests can use fixed seeds for deterministic runs. Its generator DSL creates common Java types, constrains values, and combines or converts generators for custom types. QuickTheories works with JUnit, TestNG, and other test frameworks; `checkAssert` supports assertion libraries such as AssertJ and Hamcrest. The `forAll` API handles theories over one to four generated values. System properties configure seeds, example counts, and shrink attempts, while named profiles can reuse settings. An experimental coverage feature targets new code paths, but may reduce performance by about 10% and interfere with JaCoCo or other coverage systems. The project uses the Apache-2.0 license.

Scala Hedgehog is a property-based testing system for Scala that generates values to check properties and can simplify failing cases while preserving the generated values’ invariants. Range combinators let developers set the scope of generated numbers and collections. For stateful software, its abstract state machine testing can model systems such as web services and database layers. The project includes an SBT test runner and integration modules for Minitest and MUnit; its documentation also describes Gradle support through a Scala plugin. Documented Scala versions are 2.12, 2.13 and 3.3 or later. Binary dependencies for its modules are published through Maven Central, and the core module has no external dependencies. Scala Hedgehog is free, with no paid plans listed. The project describes its release as early and says its API may change before wider adoption. IntelliJ’s Scala plugin does not list Hedgehog among its built-in test frameworks, though Properties tests can be run as applications. The getting-started documentation assumes SBT; SBT 1.9.1 and later support the testing extension by default, while earlier versions require a testFrameworks setting.