Worked on stabilizing large-scale test executions in the microsoft/playwright repository by addressing a RangeError that occurred during extensive test runs. The solution involved reworking the test runner’s approach to creating test groups, enabling more balanced distribution of tests across workers and preventing failures when thousands of tests were executed concurrently. This change improved the reliability and efficiency of continuous integration pipelines, reducing flaky failures and shortening developer feedback loops. The work demonstrated strong skills in TypeScript, software development, and testing, with a focus on concurrency and performance optimization within Node.js-based test infrastructure. No new features were added during this period.