Contributed to the uutils/coreutils repository by developing a targeted regression test suite for Hungarian locale date formatting, focusing on validating the correctness of date command outputs under localized conditions. This work emphasized expanding test coverage to strengthen internationalization reliability and reduce the risk of locale-specific regressions in critical utilities. Leveraging Rust and test-driven development practices, the developer integrated these tests into the continuous integration workflow, enhancing feedback and release readiness. The approach centered on localization and robust testing methodologies, ensuring that future changes maintain accurate behavior for Hungarian locale users and supporting higher quality standards for internationalized command-line tools.