Worked on the pytest-dev/pytest repository to enhance the reliability of test isolation by refactoring the temporary directory management system. Addressed an established issue by replacing the previous atexit-based cleanup with a more robust ExitStack-based approach, ensuring consistent tmpdir cleanup regardless of test outcomes. Developed and integrated comprehensive tests to validate retention policies and cleanup behavior, reducing the risk of flaky tests and improving continuous integration stability. This work demonstrated strong proficiency in Python, pytest internals, and integration testing, focusing on strengthening the temporary directory lifecycle and contributing collaboratively to the core testing infrastructure over the course of the month.