QuickTheories vs Rantly
QuickTheories
github.comRantly
github.comSide by side
| Figure | QuickTheories | Rantly |
|---|---|---|
| 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) | 7.3 (#17) |
| License | The repository identifies its license as Apache-2.0. | The project code is published under the MIT License. |
| Purpose | QuickTheories is a property based testing library for Java 8, described as a Java version of QuickCheck. | Rantly generates random test data and provides a Test::Unit extension for property-based testing. |
| Shrinking | It automatically tries to find smaller or simpler values that still falsify a property, without requiring custom shrinking code for each type. | Optional shrinking can reduce failing values; the documented search is limited to at most 1024 shrinking operations and does not fully traverse the failure tree. |
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.