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

Selenium

https://pypi.org/project/selenium/

JUnit

https://junit.org/junit5/
Programming language

Python

Java

Category

Web Automation

Unit Testing, Regression Testing

General info

Selenium is an open source tool used to test web applications

Selenium is a powerful testing tool which can send standard Python commands to different browsers, despite variations in browser design. It also provides extensions to emulate user interaction with browsers, a distribution server for scaling browser allocation, and the infrastructure for implementations of the W3C WebDriver specification that lets you write interchangeable code for all major web browsers

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
xUnit
Set of frameworks originating from SUnit (Smalltalk's testing framework). They share similar structure and functionality.

No

Yes

It is an instance of the xUnit architecture for unit testing frameworks.
Client-side
Allows testing code execution on the client, such as a web browser

Yes

It is primarily a browser automation tool which tests front-end components and functionality

Yes

You can test front-end components such as individual classes and functions that create the front-end
Server-side
Allows testing the bahovior of a server-side code

Yes

It can perform Unit tests and can test various components and behaviours in the backend using a BDD or TDD approach

Yes

You can test classes and functions that compose the back-end such as database connections and so on
Fixtures
Allows defining a fixed, specific states of data (fixtures) that are test-local. This ensures specific environment for a single test

Yes

By writing your Selenium WebDriver tests in PyTest, this gives you access to Pytest's powerful fixture model

Yes

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

One can group fixtures if accessing Pytest's fixture model

Yes

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

By using a library such as Faker or Fake-factory

You can use JUnit-quickcheck to generate test data
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)

Yes

It includes support for mocking

JUnit does not support mocking internally but you can use a mock framework like Mockito to generate mock objects.
Grouping
Allows organizing tests in groups

Yes

By using the TestNG feature with which we can create groups and maintain them easily

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.
Other
Other useful information about the testing framework