Worked on the ferrocene/ferrocene repository to enhance the Rust lexer’s resilience by developing a comprehensive whitespace handling test suite. Focused on documenting and validating the lexer’s behavior with vertical tab, zero-width space, and other Pattern_White_Space characters, the work aligned tokenization with both parser and standard library expectations. Leveraged Rust and testing best practices to improve error handling for invalid whitespace, reduce production risk, and support faster debugging of edge cases. Improved project documentation and test hygiene by updating the README and adding explicit run-pass directives, establishing a solid foundation for future improvements in lexical analysis and error reporting.