Worked on the NixOS/nix repository to enhance the stability of macOS test scripts, focusing on improving continuous integration reliability. Addressed a persistent issue with intermittent crashes in shell.nix tests by introducing explicit shebangs, ensuring consistent script execution across environments. This targeted bug fix reduced flaky test behavior, accelerated feedback cycles for macOS changes, and lowered maintenance overhead for developers. The work demonstrated careful attention to cross-platform compatibility and maintainable test tooling, utilizing shell scripting and testing expertise in the Nix language. The approach aligned with project goals for resilient infrastructure and contributed to a smoother development experience for macOS users.