Developed the External Configuration Unit Testing API for the microsoft/winget-cli repository, introducing both synchronous and asynchronous testing capabilities for configuration units through the COM interface. Leveraging C++ and IDL, the work exposed new TestUnit and TestUnitAsync methods on the ConfigurationProcessor, allowing external systems to automate configuration testing and reducing manual QA effort. The updated interface definitions and test hooks improved maintainability and set a foundation for future extensibility. This feature enhanced integration reliability and enabled broader automation, supporting more robust CI/CD workflows and partner integrations. The work demonstrated depth in C++ development, COM API design, and configuration management.