CogniPrep developers highlight importance of content integrity tests over code validation

CogniPrep, a content-heavy Next.js application, relies on TypeScript registries to manage hundreds of practice tests and pages. These registries have a failure mode where missing entries don't crash but instead create incorrect content or broken links. Developers implemented registration tests that verify file existence and icon consistency across components, catching errors the type checker misses. These tests ensure content promises match actual routes, preventing costly 404 errors in sitemaps. The tests focus on verifying content truthfulness rather than just code behavior.