Software-in-the-Loop Testing (glossary)
In software-in-the-loop testing, the actual Production Software Code is incorporated into the mathematical simulation that contains the models of the Physical System. This is done to permit inclusion of software functionality for which no model(s) exists, or to enable faster simulation times. (Argonne National Lab 2012)
Argonne Naltional Lab. 2012. Model based design definition of terms. Available at http://www.autonomie.net/references/model_based_design_defs_24c.html.
This is one of three related techniques: model-in-the-loop, software-in-the-loop, and hardware-in-the-loop.