Migrate from `MSTest.TestFramework` to `xunit`

[JamieMagee]

There are 3 major testing frameworks for .NET: MSTest^1, xunit^2, and NUnit^3. MSTest was (likely) chosen for Component Detection as it was the default test framework when creating a new project in Visual Studio.

Out of the 3 frameworks xunit has the most downloads. Currently MSTest has 146M, NUnit 194M, and xunit has 273M. That alone shows that xunit has more developer mindshare. Some other benefits include:

• [SetUp] and [TearDown] are not included to promote cleaner tests
• Attributes and classes aren't sealed allowing for easy extensibility

References:

• xUnit documentation
• Migrating from MSTest to xUnit.net
• Comparing xUnit.net to other frameworks
• NUnit vs. XUnit vs. MSTest: Comparing Unit Testing Frameworks In C#