Developed a robust testing infrastructure for the GoodBooks backend, focusing on financial data transfer objects within the medhatelmasry/GoodBooks repository. Leveraging C#, xUnit, and CI/CD practices, the work introduced a dedicated unit test project that validates serialization, deserialization, and data integrity for critical financial flows. The continuous integration pipeline was updated to automatically execute these backend tests on every build, providing earlier feedback and improving code confidence. This approach enhanced maintainability and test coverage for financial components, reducing production risk and enabling faster regression detection. The work demonstrates a methodical approach to backend quality and automated testing in C# environments.