QuickTheories vs Rapid
QuickTheories
github.comRapid
pgregory.netSide by side
| Figure | QuickTheories | Rapid |
|---|---|---|
| Price from | Free | Free |
| Free plan | Yes | Yes |
| Free trial | — | — |
| Open source | — | — |
| API | Yes | — |
| Self-hosted | Yes | Yes |
| Plans published | 1 | 1 |
| Spec score · Property-Based Testing Tools | 7.7 (#10) | 7.1 (#18) |
| Configuration | The QT_SEED, QT_EXAMPLES, and QT_SHRINKS system properties configure the random seed, examples per theory, and shrink attempts. | Rapid's options can be set with flags prefixed -rapid. or corresponding RAPID_ environment variables. |
| License | The repository identifies its license as Apache-2.0. | Rapid is licensed under the Mozilla Public License Version 2.0. |
Plans
In their own words
QuickTheories
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.