Experimental frames have been used in DEVS-based simulations to drive scenarios through injecting inputs and interpreting outputs. This design has traditionally called for separate models with distinct roles: generator, acceptor, and transducer. In certain controlled experiments such as model testing, sequential programming offers a simpler design with many benefits, specifically: code reduction, test case development throughput, and diagnostics for failed tests. This research offers a test framework that is derived from atomic DEVS and facilitates testing through scripting. The challenge for this research is to prove DEVS semantics are maintained when the experimental frame is tightly controlled by a script. Our solution uses a separate thread for this script and synchronizes program execution switching with a nest lock. Synchronization is key in showing that this design maintains DEVS semantics by nesting script code within the state transition functions of DEVS modeling components.