Yufan Kambang enhanced the reliability of the email handling workflow in the UserOfficeProject/user-office-core repository by expanding unit test coverage for the StfcEmailHandler component. Using TypeScript and a disciplined approach to backend development and testing, Yufan implemented tests that addressed both success and error scenarios during call creation events. The work included refactoring test descriptions to improve clarity and maintainability, making the test suite more accessible for future contributors. Although no major bugs were fixed during this period, the improvements reduced production risk and laid the foundation for faster, safer iterations by enabling earlier regression detection through stronger unit testing.