When to Apply: Reference when writing Java unit tests with JUnit 5, using @MethodSource/@CsvSource for parameterized tests, integrating Mockito for mocking, or creating custom JUnit extensions. Triggers on "JUnit 5", "JUnit", "@Test", "@MethodSource", "Mockito".
Playbook Deep Dive (11 sections): §1 Project Setup & Configuration · §2 Test Lifecycle & Structure · §3 Parameterized Tests · §4 Mockito Integration · §5 Nested & Dynamic Tests · §6 AssertJ Fluent Assertions · §7 Conditional Execution & Assumptions · §8 Custom Extensions · §9 CI/CD Integration · §10 Debugging Table · §11 Best Practices
The agent loads from 2 on-demand reference files (advanced-patterns.md, playbook.md) containing detailed implementation guides, cloud integration patterns, debugging tables, and language-specific best practices.