This paper outlines some basic testing guidance provided by the Microsoft Dynamics® AX 2009 internal development team in support of Independent Software Vendors (ISV) building product extensions for the product. Much of this guidance also applies to Microsoft Dynamics AX implementation partners and customers who are customizing the application. Ensuring that an ERP application works after it is deployed at a customer site is an extremely challenging endeavor. The base application, which is both broad and deep, has a myriad of modules, features, software and hardware configurations. ISVs extend or modify the base application to provide functionality for specific market needs and verticals. Finally, implementation partners or customers do point customizations to address specific customer needs. This combination of base application, one or more ISV add-ons, and point customizations that operate in a unique hardware and software configuration is what businesses depend on for mission critical financial data and company operations. A challenge, indeed! ISVs and implementation partners typically do not have much guidance or tooling available to help in their efforts to guarantee a quality deployment for customers. This paper is a first step in providing some guidance. Over time, this guidance will evolve and tools will come on-line to better support the AX ecosystem. There are many factors that impact the quality of software. This paper will address only a few factors that are typically associated with the discipline of software testing.