Top 20 NuGet testing Packages

Acceptance Test Driven Development and Executable Specifications for .Net
FsCheck.Xunit integrates FsCheck with xUnit.NET by adding a PropertyAttribute that runs FsCheck tests, similar to xUnit.NET's FactAttribute. All the options normally available in vanilla FsCheck via configuration can be controlled via the PropertyAttribute.
This package includes the nunit3-console runner and test engine for version 3 of the NUnit unit-testing framework. Any extensions, if needed, may be installed as separate packages.
This extension allows NUnit to recognize and load solutions and projects in Visual Studio format. It supports files of type .sln, .csproj, .vbproj, .vjsproj, .vcproj and .fsproj.
This extension sends specially formatted messages about test progress to TeamCity as each test executes, allowing TeamCity to monitor progress.
ASP.NET Core web server for writing and running tests.
NSubstitute is a friendly substitute for .NET mocking frameworks. It has a simple, succinct syntax to help developers write clearer tests. NSubstitute is designed for Arrange-Act-Assert (AAA) testing and with Test Driven Development (TDD) in mind.
NUnitLite provides a simple way to run NUnit tests, without the overhead of a full NUnit installation. It is suitable for projects that want to have a quick way to run tests using a console runner and don't need all the features of the NUnit engine and console runner. Supported platforms: - .NET Fr...
Cross-platform performance benchmarking and testing framework for .NET applications.
Utilities to streamline unit testing in Dynamics CRM 2016 by faking the IOrganizationService against an In-Memory context which runs blazingly fast.
Utilities to streamline unit testing in Dynamics CRM 365 by faking the IOrganizationService against an In-Memory context which runs blazing fast.
A picture's worth a 1000 tests. Unit testing asserts can be difficult to use. Approval tests simplify this by taking a snapshot of the results, and confirming that they have not changed.
Library for running Xamarin.Forms inside of unit tests
Common helper classes developed with ApprovalTests
Sourcery for SauceLabs - Unlocking SauceLabs capability
The most powerful free mocking library available for .NET developers.
Machine.Specifications (MSpec) adapter for .NET Framework and .NET Core including dotnet cli (dotnet test), Visual Studio IDE, TFS, Visual Studio Online, Visual Studio Team Services.
Advanced testing library for F#
A suite of Roslyn based convention specifications for enforcing code conventions in your codebase
Utilities to streamline unit testing in Dynamics CRM 2015 by faking the IOrganizationService against an In-Memory context which runs blazingly fast.