Worked on the mathworks/arrow repository to enhance test coverage and stability for core data processing features. Focused on expanding and refining tests for the DayTimeIntervalBuilder, including append operations and constructor variations, to ensure robust time-interval handling. Developed additional R and C++ tests for join and aggregation paths, addressing edge cases such as duplicate column names and incompatible key types. Improved the development workflow by introducing an explicit R dependency mirror, which increased build reproducibility, and cleaned up obsolete tests and documentation. Demonstrated strong skills in C++, R, and software testing, contributing to more reliable and maintainable code releases.