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

JUnit

https://junit.org/junit5/

TestNG

https://testng.org/doc/documentation-main.html
Programming language

Java

Java

Category

Unit Testing, Regression Testing

Unit Testing, Intergration Testing, End-to-End Testing

General info

JUnit is an open source Unit testing framework for java

JUnit is useful for developers to write and run repeatable tests. JUnit has been crucial in the development of test driven development and is partof the xUnit family of unit 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

It is an instance of the xUnit architecture for unit testing frameworks.

No

Client-side
Allows testing code execution on the client, such as a web browser

Yes

You can test front-end components such as individual classes and functions that create the 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 classes and functions that compose the back-end such as database connections and so on

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

JUnit contains a setUp() method, which runs before every test invocation and a tearDown() method, which runs after every test method.

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

You can use setUp() and tearDown() inbuilt functions as group fixtures.

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.

You can use JUnit-quickcheck to generate test data

N/A

Licence
Licence type governing the use and redistribution of the software

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)

JUnit does not support mocking internally but you can use a mock framework like Mockito to generate mock objects.

Yes

By Use of an external library like mockit which intergrates well with testNG
Grouping
Allows organizing tests in groups

Yes

In JUnit you can create a test suite that bundles a few unit test cases and runs them together. You use both @RunWith and @Suite annotation are used to run the suite test.

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