During June 2025, Mas Noble developed comprehensive Web Platform CookieStore Domain Parsing Tests for the mozilla/gecko-dev repository, focusing on robust cookie management and domain parsing validation. Using JavaScript and HTML, Mas expanded Web Platform Test coverage for cookieStore.set, targeting a range of host types including IDNA, IP addresses, and mixed-case domains. This work aimed to ensure correct cookie handling and prevent cross-domain regressions by verifying domain parsing logic under varied scenarios. Although no high-severity bugs were addressed, the depth of testing improved long-term reliability and maintainability of cookie-related features, strengthening the overall quality of the web platform’s cookie infrastructure.