Worked on the apple/container repository to enhance the stability and reliability of the UI ProgressBar component using Swift and testing best practices. Addressed a crash issue that occurred when negative progress values were provided by implementing logic to clamp the bar length to non-negative values, ensuring the UI remained robust under edge cases. Added targeted regression tests to verify that negative inputs no longer caused crashes, thereby improving overall code health and reducing crash reports. Focused on bug fixing and thorough test coverage, the work emphasized maintaining a stable user experience and preventing similar regressions in future updates to the component.