Worked on the DefinitelyTyped/DefinitelyTyped repository to enhance the reliability of QUnit test definitions by enforcing the requirement of a callback function for 'todo' tests and removing invalid signatures. This update ensured that all 'todo' tests were properly defined and executable, directly improving the stability of continuous integration pipelines and reducing false negatives in test results. The work involved careful review and modification of TypeScript type definitions, with a focus on testing best practices and code maintainability. Demonstrated proficiency in TypeScript, testing methodologies, and collaborative pull request workflows while contributing to the maintainability and onboarding experience for future contributors.