A framework for building, analyzing, systematically testing and debugging asynchronous reactive software. P# is used by engineers in Azure to design, implement and thoroughly test distributed systems and services.

The P# framework provides:

• Language extensions to C# for building event-driven asynchronous applications, writing test harnesses, and specifying safety and liveness properties.
• A systematic testing engine that can capture and control all specified nondeterminism in the system, systematically explore the actual executable code to discover bugs, and report bug traces. A P# bug trace provides a global order of all communication events, and thus is easier to debug.
• Support for replaying bug traces, and debugging them using the Visual Studio debugger.

Read the P# programming guide and then read about various features and topics here.

Follow the instructions to build P# from source, or just install our latest P# NuGet package.

We welcome contributions! However, before you start contributing, please read carefully the development guidelines.

If you are interested in using P# in your project, or have any P# related questions, please send us an email or open a new issue.