Developed and delivered ShadowOS lseek support with file descriptor offset tracking for the robolectric/robolectric repository, enhancing the fidelity of I/O operations in JVM-based Android unit tests. The implementation introduced a per-file-descriptor offset map to accurately maintain file positions, supporting SEEK_SET and SEEK_CUR operations while safely defaulting to the original lseek behavior for other cases. This approach improved test reliability and compatibility for I/O-heavy code paths, enabling broader scenario coverage and reducing test flakiness. The work demonstrated proficiency in Java, Android development, and unit testing, with careful integration into existing ShadowOs logic and attention to robust data structure design.