xUnit.net is a free, open source, community-focused unit testing tool for the .NET Framework. xUnit.net works with C# and F# inside Visual Studio, Visual Studio Code, NCrunch, ReSharper, and Rider. It is part of the .NET Foundation, and operates under their code of conduct. It is licensed under Apache 2 (an OSI approved license).

Started by @jnewkirk and @bradwilson in 2006 while they were at Microsoft, the first release was in 2007; in 2024, xUnit.net celebrated its 17th anniversary with 16 releases, including the long-anticipated v3 release. Its packages have been downloaded billions of times on NuGet, and is one of the most widely used testing frameworks for .NET.

Despite the wide popularity of the project, the primary work is being done today by just a single person (with the help of community contributions, of course!). @bradwilson retired in 2022, and xUnit.net now is his sole programming outlet.

If you've used xUnit.net in the past and enjoyed it, we would love your support! ❤️