Test Data Skill

Bad test data leads to flaky tests, test interdependence, and production data leaking into dev. Good test data is isolated, realistic, and generated programmatically.

When to Activate

• Setting up test infrastructure for a new project
• Tests are slow because they share state
• Tests fail when run in different order (order-dependent tests)
• Writing integration tests that need DB rows
• Creating realistic seed data for development
• Replacing hard-coded fixture JSON files with programmatic factory functions
• Ensuring production data is anonymized before being restored to a staging or development environment
• Choosing between transaction rollback, truncation, or unique-ID strategies for test isolation

Core Principles