JUnit 5
JUnit 5 is the next generation of JUnit. The goal is to create an up-to-date foundation for developer-side testing on the JVM. This includes focusing on Java 8 and above, as well as enabling many different styles of testing.
Web: https://junit.org/junit5/
Code: https://github.com/junit-team/junit5
JUnit 4
JUnit is a simple framework to write repeatable tests. It is an instance of the xUnit architecture for unit testing frameworks.
Web: https://junit.org/junit4
Code: https://github.com/junit-team/junit4