Worked on enhancing the robustness of string formatting in the google/cel-go repository by implementing comprehensive edge-case tests for the String.Format function. Focused on scenarios involving negative integers across binary, octal, and hexadecimal formats, as well as special floating-point values such as NaN and both positive and negative infinity. Leveraged Go for both the core implementation and the testing framework, ensuring that the new tests are tightly integrated with existing workflows. This effort improved the reliability and maintainability of the codebase, reducing the risk of regressions and supporting future refactoring by providing thorough coverage of complex formatting behaviors.