Yuan Zhou worked on the IBM/velox repository, focusing on refining the build system to improve test reliability and CI efficiency. He implemented a targeted fix that gated the DWIO test builds behind the VELOX_BUILD_TESTING flag, ensuring that these tests are only built when testing is explicitly enabled. By restructuring the build configuration and moving DWIO tests into a dedicated subdirectory, Yuan addressed issues where tests were unintentionally built when the GPU was enabled. Utilizing C++, CMake, and CI/CD practices, his work aligned the build process with intended testing configurations, reducing unnecessary CI time and enhancing determinism in the testing workflow.