A component of a well system can be tested by pressurizing the component of the well system a test pressure via two supply lines connected to the component of the well system, e.g. a choke line and a kill line. Then, a first of the two supply lines can be isolated from the second supply line and the component of the well system. The change in pressure can be measured in the first supply line and the change in pressure can be independently measured in the second supply line and the component of the well system. The change in pressure of the first supply line can be subtracted from the change in pressure of the second supply line and the component. Then, the change in pressure for the component can be analyzed to determine if the component of the well system is maintaining pressure integrity, i.e. leaking or not leaking.