JUnit 5 framework is a great work done by JUnit team specially how they made it modular and extensible. Backward compatibility makes it a right candidate for software development teams to quickly upgrade their testing framework without migrating their existing tests and start using JUnit Jupiter for new ones. These slides and demos cover some if the features of JUnit 5. Its gives you good starting point to begin learning about this awesome framework. Source code for demos presented is available on github: https://github.com/Rednirus/JUnit5

1. S U R I N D E R
2 2 N D F E B R U A R Y , 2 0 1 9
JUnit 5
Disclaimer : Only for learning and knowledge sharing purposes

2. Agenda
• Motivation for Junit 5
• Architecture of Junit 5
• Features
• Demo
• Questions

3. Motivation
• Modularity-> Big ball of mud(A Junit.jar)
• Test discovery and execution are tightly coupled
• Extensibility-> lot of room for improvement
• Java 8 and beyond?
• Not Composable
• Parameterized and SpringRunner together ? No way

4. How it started
• Junit lambda- Crowdfunding Campaign
• Initiated by Johannes Link and Marc Phillip
• Ran from July to October 2015
• Raised 53,937 Euros from 474 individuals and companies
• 4 companies donated 6 weeks of developer time.
• Created from scratch using java 8

5. Junit 5 in a Nutshell
• Modular
• Extensible
• Modern
• Backward compatible

6. Junit 5 Architecture

7. Junit 5 Architecture cont…

8. Junit Jupiter
• Programming model
• How you write tests
• Test API
• Annotations
• Assertions
• Assumptions
• Type of tests
• Extension Model
Register extensions

9. What does JUnit Jupiter need
• Java 1.8: to use lambdas and streams
• Spring 5: to use SpringExtensions

10. Dependencies

11. JUnit 5 Features

12. Junit 5 Features
• Annotations, Assertions
• Exceptions
• DisplayName for tests
• Timeouts on APIs
• Ordering tests
• Conditional Disabling the tests
• Tagging and Filtering
• Nested Tests
• Dependency Injection to test methods
• Repeated Tests
• Parameterized Tests
• Extensions
• Dynamic Tests

13. Basic APIs

14. Assert exceptions on actual API
Junit 4:
Junit 5:

15. Assert timeouts on actual API
Junit 4:
Junit 5:

16. Disable Tests on Condition

17. Test Display names of your choice

18. Run Test cases in sequence
• Run tests scenarios in order
• Add @TestMethodOrder on test class
• Add Order(sequence number ) on test methods

19. Nested Tests
• Best suited when a file has large no of test cases
• Manage related test scenarios under common heading
• Test case is more readable
• e.g. Logical grouping of test cases for Stack operations

20. Repeated Tests
• Run same test multiple times as desired
• Run lifecycle callback methods just like usual test case
• Access to current and total repetitions

21. Parameterized Tests
• Run a test on different inputs
• Provide various input data providers
• Value Source, Method Source, CsvSource to name a few

22. JUnit Jupiter – Extension model
• Extension
• Marker interface
• Org.junit.Jupiter.api.extension
• Package containing all extension APIs
• Implement as many you like
• @ExtedWith(…)
• Used to register one or more extensions
• Meta annotations

23. Execution Mode
• Same thread, Concurrent
• Enable disable Parallelism
• Can define parallelism strategy: fixed or dynamic
• No of threads configuration based on CPU cores
• Enable above properties from file

24. Where can I find the source code ?
• Source code GitHub repo:
• https://github.com/Rednirus/JUnit5
• Source code for snapshots presented in the slides
• Some additional features not covered in slides
• Repository is public
• Feedback and suggestions ? Inbox me on LinkedIn:
• https://www.linkedin.com/in/surinderkmehra/

25. References
• https://junit.org/junit5/docs/current/user-guide/
• https://www.youtube.com/watch?v=K7g2HUhWbNE
• https://www.youtube.com/watch?v=0qI6_NKFQsY
• https://www.linkedin.com/learning/learning-junit-5
• https://junit.org/junit5/docs/5.0.1/api/overview-summary.html

26. Questions