scenario-testinglisted

# Scenario-Driven Testing for AI Code Generation ## Core Principle **The Iron Law**: "NO FEATURE IS VALIDATED UNTIL A SCENARIO PASSES WITH REAL DEPENDENCIES" Mocks create false confidence. Only scenarios exercising real systems validate that code works. ## The Truth Hierarchy 1. **Scenario tests** (real system, real data) = **truth** 2. **Unit tests** (isolated) = human comfort only 3. **Mocks** = lies hiding bugs As stated in the principle: "A test that uses mocks is not testing your system. It's testing your assumptions about how dependencies behave." ## When to Use This Skill - Validating new functionality - Before declaring work complete - When tempted to use mocks - After fixing bugs requiring verification - Any time you need to prove code works ## Required Practices ### 1. Write Scenarios in `.scratch/` - Use any language appropriate to the task - Exercise the real system end-to-end - Zero mocks allowed - Must be in `.gitignore` (never commit) ### 2. Promote Patterns to `scenarios.jsonl` - Extract recurring scenarios as documented specifications - One JSON line per scenario - Include: name, description, given/when/then, validates - This file IS committed ### 3. Use Real Dependencies External APIs must hit actual services (sandbox/test mode acceptable). Mocking any dependency invalidates the scenario. ### 4. Independence Requirement Each scenario must run standalone without depending on prior executions. This enables: - Parallel execution - Prevents hidd