RSpec vs NUnit comparison of testing frameworks
What are the differences between RSpec and NUnit?

	RSpec https://rspec.info	NUnit https://nunit.org/
Programming language	Ruby	.NET
Category	Unit Testing, Intergration Testing	Unit Testing
General info	Domain Specific Language (DSL) testing solution for Ruby code It focuses on empowering Test Driven Development (TDD). RSpec contains multiple smaller libraries, which may be independently used with other testing frameworks.	NUnit is an open-source unit testing framework for Microsoft .NET. NUnit was Initially ported from JUnit. Tests can be run from a console runner, within Visual Studio through a Test Adapter or through 3rd party runners. Tests can be run in parallel and has Strong support for data driven tests. Unit supports multiple platforms including .NET Core, Xamarin Mobile, Compact Framework and Silverlight.
xUnit Set of frameworks originating from SUnit (Smalltalk's testing framework). They share similar structure and functionality.	Yes Yes, but it differs from more traiditional xUnit solutions. Its tests are written in a "Tests as Specification" manner. This means that the terminology used in RSpec is adjusted to a language more fitting for specification.	Yes Nunit is one of many programs in the xUnit family
Client-side Allows testing code execution on the client, such as a web browser	Yes RSpec is used to primarily test the behaviour of applications or individual components so it can test front-end behaviour as well - you can use capybara gem with RSpec for that.	Yes You can test front-end components with NUnit since it is a Unit testing framework the application is isolated into diverse modules which are tested independently
Server-side Allows testing the bahovior of a server-side code	Yes You can test server-side behaviour with Rspec	Yes You can test back-end components with NUnit, it is a Unit testing framework hence the application is isolated into diverse modules which are tested independently
Fixtures Allows defining a fixed, specific states of data (fixtures) that are test-local. This ensures specific environment for a single test	Yes RSpec does contain fixture methods	Yes NUnit contains the fixture methods SetUp to initialize your test environment and TearDown method to destroy a test environment
Group fixtures Allows defining a fixed, specific states of data for a group of tests (group-fixtures). This ensures specific environment for a given group of tests.	Yes Group fixture methods are supported	Yes Group fixtures are available in NUnit
Generators Supports data generators for tests. Data generators generate input data for test. The test is then run for each input data produced in this way.	Yes RSpec contains generators for example intergration_'test_name' which will save a spec inside the spec/requests folder	N/A
Licence Licence type governing the use and redistribution of the software	MIT License	MIT License
Mocks Mocks are objects that simulate the behavior of real objects. Using mocks allows testing some part of the code in isolation (with other parts mocked when needed)	Yes Available through rspec-mocks gem.	Yes You can create mock objects using the third party library moq
Grouping Allows organizing tests in groups	Yes Allows declaring example groups and contexts.	Yes You can group tests into suites with NUnit
Other Other useful information about the testing framework