Worked on stabilizing time-based tests for the birdnet-go repository, focusing on improving the reliability of nighttime filtering logic across multiple time zones. Addressed test flakiness by setting test dates to UTC midnight and dynamically deriving longitude from the local timezone offset, ensuring that solar times align with local noon regardless of region. Verified consistent test behavior in environments such as CDT, UTC, NZST, JST, HST, Europe/London, and Americas/Buenos_Aires. All improvements were isolated to the test suite, leaving production filtering logic unchanged. Utilized Go for implementation, applying skills in data filtering, testing, and timezone handling throughout the process.