Unit Testing Skill

Framework-agnostic unit testing best practices. Apply these patterns regardless of language or test runner.

Core Principles

1. Test behavior, not implementation — tests should survive internal refactoring
2. One behavior per test — not one method per test
3. AAA structure — Arrange / Act / Assert, always
4. Prefer fakes and spies over mocks — less coupling to mocking frameworks
5. Name tests as readable sentences — a non-developer should understand the scenario

Workflow

Writing New Tests

1. Identify the unit of behavior (a business scenario, not a method)
2. Name the test using Subject_Scenario_ExpectedBehavior pattern
3. Structure with AAA — keep each section minimal