During December 2024, Guido focused on enhancing end-to-end test coverage for subscription purchases via RC Paywalls in the purchases-js repository. He developed and integrated a new Purchase Flow Validation Test, which included both a dedicated test function and setup modifications to support the RC Paywall offering ID. Using JavaScript, TypeScript, and Playwright, Guido ensured that the subscription product purchase flow through RC Paywalls is thoroughly validated. This work improved the reliability of production deployments by reducing risk and established a robust foundation for future paywall-related validation tests. The depth of the implementation reflects careful attention to test architecture and maintainability.