Top 20 NuGet testing Packages

Integration testing against e-mail almost always sucks. EmbeddedMail doesn't remove all of that pain, but it certainly helps it suck less by providing an in-memory SMTP server that you can assert on.
A set of simple assert extensions to give you more choices and easier to read tests
PhantomJS is a headless WebKit scriptable with a JavaScript API. It has fast and native support for various web standards: DOM handling, CSS selector, JSON, Canvas, and SVG.
Abp.TestBase
A unit test library for .NET that allows you to build tests for FluentValidation rules in easy way.
Classes to randomly generate data for unit tests. Powered by AutoFixture.
Extensions and helpers to make unit testing with NUnit a little easier
.NET Unit test helpers for ASP.NET MVC routing and for asserting that ASP.NET MVC controller actions return expected results
Through a fluent, extensible interface, NBuilder allows you to rapidly create test data, automatically assigning values to properties and public fields that are one of the built in .NET data types (e.g. ints and strings). NBuilder allows you to override for properties you are interested in using lam...
Machine.Specifications.Should is a should library for the Context/Specification framework Machine.Specifications
Unit testing framework for Sitecore.
FsCheck.NUnit integrates FsCheck with NUnit by adding a PropertyAttribute that runs FsCheck tests, similar to NUnit TestAttribute. All the options normally available in vanilla FsCheck via configuration can be controlled via the PropertyAttribute.
Easy-to-use test run reporter for MSTest
NUnit console and Visual Studio runner for .NET Core and .NET 4.5.1+
White is a framework for automating rich client applications based on Win32, WinForms, WPF, Silverlight and SWT (Java) platforms. It is .NET based and does not require the use of any proprietary scripting languages. Tests/automation programs using White can be written with whatever .NET language, ID...
Key mouse emulation can be performed on Windows applications at high speed and with high accuracy. This library is built on Friendly Layer.
Specify is a .Net testing library that builds on top of BDDfy from TestStack
Specify is a .Net testing library that builds on top of BDDfy from TestStack
A library for unit testing AspNetCore routes
Additional AutoMapper extension methods for SparkyTestHelpers.Mapping (Unit test helpers for asserting public properties on class instances "mapped" from one type to another have the correct values.)