Abstract: A system to test barrier pressure includes a Christmas Tree (XT) coupled to a wellbore including a downhole pressure barrier. The XT includes a first valve along a flow path and a second valve coupled to the flow path. The system further includes a testing unit that includes a vessel fluidly coupled to the flow path. The testing unit also includes a fluid mover associated with the vessel to draw fluid into or to drive fluid out of the vessel. The testing unit further includes an actuator coupled to the fluid mover to control operation of the fluid mover. The testing unit is configured to draw a volume of fluid out of the XT and to further return the volume of fluid to the XT.