Karoly Gerner developed and refactored end-to-end test suites and GUI modules for product measurement units across the spryker/cypress-tests, spryker-shop/b2b-demo-marketplace, and spryker-shop/b2b-demo-shop repositories. He focused on enhancing test reliability and maintainability by introducing repository-pattern selectors, dynamic fixtures, and shared test helpers using JavaScript, TypeScript, and Cypress. His work included building a new measurement units GUI module, integrating it into multiple shop environments, and improving test data management. By stabilizing dependencies and refining the page object model, Karoly enabled faster, more reliable UI iterations and robust release cycles, addressing both backend and frontend testing requirements.