Worked on the vertexproject/synapse repository to enhance the reliability of the SMTP email validation test suite. Focused on stabilizing test cases by updating them to accurately reflect message content and ensure robust validation of email attributes, directly addressing a bug that previously caused inconsistencies. This effort reduced CI flakiness and improved test coverage for email-related workflows, making future changes to SMTP handling safer and more predictable. Utilized Python and testing frameworks to align test expectations with real validation logic, reinforcing quality gates and supporting maintainable development practices. The work emphasized depth in test reliability rather than feature expansion during the period.