Dean Smith enhanced instrumentation testing capabilities for Android projects in the facebook/buck2 and facebook/buck2-prelude repositories. He developed features allowing tests to simulate actions as a secondary user, controlled by the RUN_AS_SECONDARY_USER environment variable, while maintaining default primary-user behavior. This approach improved test coverage and realism, enabling more comprehensive and reliable CI workflows. Dean aligned testing frameworks across both repositories, ensuring consistent behavior and easier maintenance. His work leveraged Java and Kotlin, focusing on Android development and robust testing practices. The depth of these changes addressed cross-repo parity and maintainability, with thorough documentation and governance artifacts supporting long-term sustainability.