Karrui Lau enhanced the FormSG repository by developing a Chromatic story and comprehensive UI tests for the public form thank-you page. Using JavaScript and TypeScript, Karrui implemented mock responses to simulate both successful submissions and forms without sections, ensuring robust validation of the page’s rendering and the 'submit another form' user flow. The work leveraged Storybook for visual regression testing, which increased quality assurance confidence and reduced the risk of user experience regressions in production. This focused feature improved release readiness for form-facing pages, demonstrating depth in frontend development, mocking strategies, and automated testing within a collaborative open-source environment.