junit

When to use this skill

Use this skill whenever the user wants to:

• Write Java/Kotlin unit tests and extensions with JUnit 4/5
• Use assertions, lifecycle, parameterization, and mocks (Mockito, etc.)

How to use this skill

1. Use cases：@Test、@BeforeEach、@AfterEach；Assertions（assertEquals、assertThrows）；@ParameterizedTest。
2. Ecosystem: JUnit 5 + Mockito/AssertJ; Maven/Gradle dependencies and surefire configuration.
3. Run: mvn test, gradle test; IDE run and coverage.

Best Practices

• Unit tests should be independent and repeatable; avoid dependency on order and external services.
• Use mocks to isolate dependencies; keep naming and structure clear.
• Balance coverage and speed; always run in CI.

Keywords

junit, JUnit 5, unit testing, Java, Kotlin