Fox Documentation

Everything about Fox, the property-based testing tool for Objective-C and Swift.

Besides this documentation, you can also view the source on GitHub.

Getting Started

New to Fox? Or just wanting to have a taste of it? Start here.


Generators are semi-random data producers that are the core to Fox’s capabilities. Follow the links below to learn more in detail.

The Runner

All the guts around configuring and executing Fox’s verification of properties.

Parallel Testing


This section and its API is ALPHA and is subject to change. Alpha APIs are not under semantic versioning and can change freely between versions.

How to use Fox to test stateful code that executes in parallel (across multiple threads). This does not encompass async testing.