Hardware-in-the-Loop (HiL) testing is a test methodology that can be used throughout the development of real-time embedded controllers to reduce development time and improve test effectiveness. HiL testing provides a way to simulate sensors, actuators, and mechanical components so that all I/O of the electronic control units under test are connected long before the final system is integrated. With electronic control units becoming increasingly complex, the number of test combinations required to ensure correct functionality and response increases exponentially. The presented demonstration integrates two physical On-Board Units (OBU) into an Artery V2X simulation using the Robot Operating System (ROS). This allows the exchange of ETSI Cooperative Awareness Messages (CAM) and Decentralized Environmental Notification Messages (DENM) via the V2X simulation environment.