AI Regression Testing Testing patterns specifically designed for AI-assisted development, where the same model writes code and reviews it — creating systematic blind spots that only automated tests can catch. When to Activate - AI agent (Claude Code, Cursor, Codex) has modified API routes or backend logic - A bug was found and fixed — need to prevent re-introduction - Project has a sandbox/mock mode that can be leveraged for DB-free testing - Running or similar review commands after code changes - Multiple code paths exist (sandbox vs production, feature flags, etc.) The Core Problem When an…