The reason for establishing a standard for testing microgrid controllers, in the context of enabling interoperability of the different controllers and components needed to operate the controller through cohesive and platform-independent interfaces, is to establish standardized testing procedures. This approach should allow for flexibility and customization of components and control algorithms to be deployed without sacrificing "plug-and-play" or limiting potential functionality, while helping to ensure minimum requirements are met and establishing comparative performance indices. The standardization focuses on testing functional requirements, while recognizing that there are many possible hardware and software implementations of the same microgrid controller generic functions. The interoperability with various Distributed Energy Resources (DER) interfaces and other electrical system interfaces within the microgrid is be considered. A standardized set of testing procedures should facilitate the wide adoption of standard microgrid controller functional and performance requirements by vendors and utilities, including the DSO, for ease of interfacing with the Distribution Management System (DMS). The standard is functionality-driven and focuses on a modular approach to the implementation of the functional requirements.