What problem does it solve? When an AI writes code and then reviews its own work, it carries the same assumptions into both steps, creating systematic blind spots where bugs survive repeated review cycles. This Skill provides testing patterns that mechanically catch AI-introduced regressions, especially sandbox/production path mismatches and incomplete SELECT clauses. ## Core Features & Use Cases - Sandbox-Mode API Testing: Configure Vitest with Next.js App Router to test API routes without a database by forcing sandbox mode via environment variables. - Bug-Driven Regression Tests: Write tests only for bugs that were actually found, naming them after the bug (e.g., "BUG-R1 regression") so the same failure cannot recur. - Bug-Check Workflow Integration: Define a custom command that runs tests and builds before any AI code review, then proposes a regression test for every fix. - Use Case: After an AI assistant fixes an API endpoint four times and misses the sandbox path each time, add a response-shape test that asserts all required fields exist, catching the regression instantly on the next run. ## Quick Start Ask the AI to set up sandbox-mode Vitest regression tests for the API routes where bugs were recently found.
