Unit Testing Patterns Skill

Purpose

Write effective, maintainable unit tests using JUnit 5, Mockito, and AssertJ that achieve 80%+ code coverage.

When to Use

• ✅ Testing business logic in services
• ✅ Testing data validation
• ✅ Testing utility functions
• ✅ Test-driven development (TDD)

JUnit 5 Patterns

Test Structure (AAA Pattern)