JUnit is generally used to test all of your application's units and components, such as classes and methods. It aids with the creation and execution of repeated automated tests to ensure that your code performs as expected. Selenium automation testing for web apps and webpages may also be done with JUnit.
JUnit is a free and open-source framework for writing and triggering tests. TestNG is a Java-based framework that provides a better way to perform tests. Runs of tests in parallel Parallel testing is not supported by JUnit. TestNG has the ability to execute tests in parallel.
JUnit is an open source unit testing tool for testing code units. It is primarily used for unit testing Java projects, but it may also be used in conjunction with Selenium Webdriver to automate Web application testing. As a result, JUnit may be used to automate the testing of a web application.
It is a collection of unit testing frameworks generally known as xUnit, and it plays a critical part in test-driven development. JUnit advocates the concept of "first testing, then coding," emphasising the importance of preparing test data for a piece of code that may be tested first and then implemented.
Both the Testng and Junit frameworks are used for Unit Testing. JUnit is similar to TestNG. TestNG now has a few extra features that make it more powerful than JUnit.