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

	Cucumber https://github.com/cucumber/cucumber-ruby	TestNG https://testng.org/doc/documentation-main.html
Programming language	Ruby	Java
Category	Acceptance Testing	Unit Testing, Intergration Testing, End-to-End Testing
General info	An automation tool for Behavior-Driven Development The specifications are written in plain texts, which allows them to be easily understandable for all stakeholders. Cucumber Framework also supports languages beyond Ruby e.g. Java, JavaScript and Scala.	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.	No	No
Client-side Allows testing code execution on the client, such as a web browser	Yes You can test the front-end part like the GUI using cucumber and selenium, they integrate well to test your front-end.	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 back-end components such as APIs using rest & soap clients, and databases using whatever client libraries were provided by the libraries that existed in those stacks	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 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 Using the cucumber extension aruba you can create fixures in two steps: 1.Create a fixtures-directory; 2.Create fixture files in this directory	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 You can group your fixtures inside your fixtures directories	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 By using all of RSpec’s supported mocking frameworks (RSpec, Mocha, RR, Flexmock)	Yes By Use of an external library like mockit which intergrates well with testNG
Grouping Allows organizing tests in groups	Yes Cucumber allows the use of tag Cucumber feature files or individual tests to group tests. Then, you can pass a Cucumber tagged expression at test execution that specifies the tag (grouped) tests to run. https://www.toolsqa.com/cucumber/cucumber-tags/	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