Extension model overview in JUnit - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the purpose of the JUnit Extension Model?

The JUnit Extension Model allows you to add custom behavior to tests, such as setup, teardown, or modifying test execution, without changing the test code itself.

beginner

Name two common extension points in JUnit 5's Extension Model.

Two common extension points are BeforeEachCallback and AfterEachCallback, which run code before and after each test method respectively.

beginner

How do you register an extension in JUnit 5?

You can register an extension by annotating the test class or method with <code>@ExtendWith(YourExtension.class)</code>.

intermediate

What is the difference between BeforeAllCallback and BeforeEachCallback?

BeforeAllCallback runs once before all tests in a class, while BeforeEachCallback runs before each individual test method.

intermediate

Why is the JUnit Extension Model useful for test code maintenance?

It helps keep test code clean by separating reusable setup or teardown logic into extensions, making tests easier to read and maintain.

Which annotation is used to apply a JUnit 5 extension to a test class?

A @ExtendWith

B @TestExtension

C @UseExtension

D @EnableExtension

The correct annotation to register an extension in JUnit 5 is @ExtendWith.

What does the AfterEachCallback interface allow you to do?

A Run code before all tests

B Modify test method parameters

C Run code after each test method

D Skip tests conditionally

AfterEachCallback runs code after each test method finishes.

Which of these is NOT a valid JUnit 5 extension point?

A BeforeAllCallback

B AfterEachCallback

C BeforeTestExecutionCallback

D TestCaseListener

TestCaseListener is not a JUnit 5 extension point.

How often does BeforeAllCallback run in a test class?

A Before each test method

B Once before all test methods

C After each test method

D After all test methods

BeforeAllCallback runs once before all tests in the class.

What is a key benefit of using the JUnit Extension Model?

A Adding reusable behavior without cluttering test code

B Writing tests without assertions

C Automatically generating test data

D Running tests in parallel

Extensions let you add reusable setup or teardown logic cleanly.

Explain how the JUnit Extension Model helps improve test code organization.

Think about how extensions reduce repeated code in tests.

Describe the difference between BeforeEachCallback and BeforeAllCallback in JUnit extensions.

Consider how often each callback runs during testing.