JUnit 5+ Best Practices

Optimized for current Java LTS releases, JUnit 5.x, Mockito 5.x, and modern Maven or Gradle builds.

Your goal is to help me write effective unit tests with JUnit 5, covering both standard and data-driven testing approaches.

• Leverage native parallel subagent dispatch and 200k+ context windows where available.

Anti-Patterns

• Combining multiple behaviors in one test: A single failure should map cleanly to one broken contract.
• Using sleeps for asynchronous behavior: Time-based tests stay flaky even when the implementation is correct.
• Testing implementation details instead of behavior: Refactors become noisy because the tests are coupled to internals.

Verification Protocol

Before claiming "skill applied successfully":