Non-Deterministic Delay Behavior Testing of Chinese Train Control System Using UPPAAL-TRON

The Chinese Train Control System level 3 (CTCS-3) is an open and real-time safety-critical system. Due to the non-deterministic delay behavior in the environment, there is a large number of stimuli to the train control system with different patterns of arrival times. Control strategies must be well considered, as either the logic of the function fails or the real-time constraints are dissatisfied, may directly lead to significant human injury or financial loss. In this paper, we introduce the notion of test specification and the relativized timed input/output conformance based on timed automata theory. A new test case generation and execution algorithm has been proposed, by which the tester can reset Implementation Under Test (IUT) whenever they want, make it more sense in specific domain fields. We apply UPPAAL-TRON based online conformance testing framework to test nondeterministic delay behavior of Radio Block Center (RBC) handover scenario of CTCS-3 against critical safety, real-time, and liveness properties (defined in the system requirement specification (SRS) documents). Our experiments show that assurance of collision avoidance and train non-derailment can be guaranteed, but emergency brake intervention may happen with low probability in this scenario under the requirements specified in the SRS document.