Menu File –> Import –> Maven –> Existing Maven Projects
Browse to your source code location
Click Finish button to finish the importing
Menu File –> Import –> Gradle Project –> Select Project --> Next until finish
Open the JUnit5UserRepositoryImplFileTest.java
Right click -> Run As -> JUnit Test or use the shortcut: Alt+Shift+x, T to start the main method
All the source code are described in: JUnit 5 Basic Introduction