Worked on enhancing the reliability of the ceph/s3-tests repository by addressing issues related to S3 Select test cases. Focused on backend development and testing using Python, the work involved implementing a fix to handle empty result sets in S3 Select operations, ensuring that assertion failures no longer occurred in rare edge cases. The solution included logic to set aggregation sums to zero when no rows matched, thereby improving test coverage for scenarios with zero-count results. These changes contributed to a more robust test suite and increased CI stability, reducing the occurrence of flaky failures and supporting more dependable automated testing.