Top 4 mstest open source projects

A very extensive set of extension methods that allow you to more naturally specify the expected outcome of a TDD or BDD-style unit tests. Targets .NET Framework 4.7, .NET Core 2.1 and 3.0, as well as .NET Standard 2.0 and 2.1. Supports the unit test frameworks MSTest2, NUnit3, XUnit2, MSpec, and NSpec3.

#1 .NET BDD Framework. SpecFlow automates your testing & works with your existing code. Find Bugs before they happen. Behavior Driven Development helps developers, testers, and business representatives to get a better understanding of their collaboration

A very simple, yet flexible, "AutoFaker" for FakeItEasy to easily auto generate classes with faked dependencies.

bUnit is a testing library for Blazor components that make tests look, feel, and runs like regular unit tests. bUnit makes it easy to render and control a component under test’s life-cycle, pass parameter and inject services into it, trigger event handlers, and verify the rendered markup from the component using a built-in semantic HTML comparer.