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

	RSpec https://rspec.info	TestNG https://testng.org/doc/documentation-main.html
Programming language	Ruby	Java
Category	Unit Testing, Intergration Testing	Unit Testing, Intergration Testing, End-to-End 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.	TestNG is a testing framework for the Java programming language inspired by JUnit and NUnit TestNG is similar to JUnit and NUnit but with newer functionalities such as: annotations, test that your code is multithread safe, flexible test configuration, support for data-driven testing (with @DataProvider), support for parameters, powerful execution model (no more TestSuite) and more... It's also designed to cover all categories of tests unit, functional, end-to-end, intergration... etc
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.	No
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 The scope of testing with testNg is wide and you can test various front-end functionalities and behaviours with it
Server-side Allows testing the bahovior of a server-side code	Yes You can test server-side behaviour with Rspec	Yes You can test server-side functionalities and behaviours with TestNg
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 Fixtures are inbuilt into testNG, these are the annotations which are: @BeforeSuite, @AfterSuite, @BeforeTest, @AfterTest, @BeforeGroups, @AfterGroups, @BeforeClass, @AfterClass, @BeforeMethod, @AfterMethod
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 You can use various fixtures to setup environments for group tests
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	Apache License 2.0
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 By Use of an external library like mockit which intergrates well with testNG
Grouping Allows organizing tests in groups	Yes Allows declaring example groups and contexts.	Yes Multiple test cases can be grouped more easily by converting them into testng.xml file, in which you can make priorities which test case should be executed first
Other Other useful information about the testing framework