Worked on the MetaMask/metamask-mobile repository to modernize the unit testing suite in preparation for React 19 and an upcoming React Native upgrade. Migrated approximately 1,386 unit tests from Enzyme to React Native Testing Library, removing legacy dependencies and updating test patterns to focus on user-visible behavior rather than internal state. Enhanced the test infrastructure by introducing targeted mocks and helpers, which decoupled tests from deep render dependencies and improved reliability. Utilized JavaScript and TypeScript to rewrite tests, refresh snapshots, and streamline maintenance, ultimately reducing technical debt and enabling faster, lower-risk platform upgrades through improved test coverage and feedback.