When working with advanced settings and rules, especially things like database calls, it’s very efficient to be able to test the settings without having to run through a complete deployment. Luckily, MDT enables you to perform a simulated deployment
by running the Gather process by itself. The simulation works best when you are using a domain-joined machine (client or server).
This script performs the Microsoft Deployment Toolkit (MDT) Gather process in a simulated MDT 2013 environment. This allows you to test the MDT gather process and check to see if it is working correctly without performing a full Windows deployment.
For more information on MDT 2013, and to download the free toolkit, see Microsoft Deployment Toolkit 2013.