JUnit 5 Extension Model

Explore the JUnit 5 extension model to understand how it enhances unit testing through flexible extension points such as lifecycle callbacks, conditional execution, parameter resolution, and exception handling. This lesson helps you grasp how to implement and customize extensions that execute at specific events during test execution, allowing more powerful and maintainable Java tests.

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Types of extension points
JUnit 5 extensions

JUnit 5 prefers extension points over features. Instead of putting all the features in the Jupiter module, JUnit 5 offers an extensible mechanism to better cater to developer needs. Creating temporary files and directories, along with verifying exceptions, are a couple of examples of this.

This philosophy is not new to the JUnit project. In JUnit 4, there is support for Rule and Runner APIs. These allow users to implement their extensions. An example of this extension is MockitoRule. It injects mocks into your unit tests.

In contrast, JUnit 5 consists of a single, coherent extension API. It’s a marker interface. This allows developers to work only ...

1.Before We Begin

2.Introduction to JUnit 5

3.Junit 5 Core Concepts

4.Dynamic Tests

5.Dependency Injection in JUnit 5

6.JUnit 5 Extensions

7.Migrating from Junit 4 to Junit 5

8.Appendix

9.BONUS: Useful Assertion Libraries

10.Conclusion

JUnit 5 Extension Model