Portable.FluentAssertions (nuget): A very extensive set of extension methods that allow you to more naturally specify the expected outcome of a TDD or        BDD-style unit test. PCL for .NET45, SL4+, WP7+, Xamarin.iOS, Xamarin.Android, Xamarin.Mac. Supports the unit test frameworks NUnit, NUnitLite, XUnit, MBUnit and MSpec.
Keywords: MSTest|xUnit|NUnit|NUnitLite|Portable|MSpec|MbUnit|TDD|BDD|Fluent