GitHub repository: mhejle/fluentassertions
Primary language: C#
Description: Fluent Assertions is a set of .NET extension methods that allow you to more naturally specify the expected outcome of a TDD or BDD-style test. We currently use it in all our internal and client projects, and it is used in many open-source projects. It runs on .NET 4.0, 4.5, 4.6, CoreClr, .NET Native, Windows 8.1, Silverlight 5, Windows Phone 8.0 and UWP. It supports the unit test frameworks MSTest, MSTest2, NUnit, XUnit, MBUnit, Gallio, NSpec and MSpec.