What are JUnit 5 extensions and how do I use them?

What are JUnit 5 extensions and how do I use them?

JUnit 5 extensions are a way to extend the functionality of JUnit tests. They allow you to add custom behavior to your tests, such as modifying the test lifecycle or providing additional features.

Can you give me an example of a common extension?

Sure! One common extension is the @ExtendWith annotation, which allows you to register extensions for a specific test class or method.

How do I create my own custom extension?

To create a custom extension, implement the Extension interface and override the methods you need, such as beforeEach or afterEach.

Are there any built-in extensions I should know about?

Yes, JUnit 5 comes with several built-in extensions like MockitoExtension for mocking and SpringExtension for Spring integration.