Complete Test Suite for the CTCS-3 Target Speed Monitor Based on IECP Test Theory

The distance-to-go curve, which performs the safety critical functions of the Chinese Train Control System Level 3 (CTCS-3), is characterized by large input domain parameters and complex fault modes. It is very difficult to completely test the distance-to-go curve of train onboard equipment. In this paper, a method of generating complete test suite for the CTCS-3 Target Speed Monitor (TSM) has been presented, based on Input Equivalence Class Partitioning (IECP) test theory. Firstly, according to the system requirement specification (SRS) of CTCS-3, the finite state machine models of TSM are built, which satisfy the different brake control modes of driver with high Priority and Automatic Train Protection (ATP) with high Priority. Secondly, the Input/Output (I/O) equivalence and the equivalence class partition theory are applied to obtain two kinds of IECPs with different braking control modes. Finally, the fault models and fault domain of system under test (SUT) are introduced. Two complete test suites of TSM are generated, which can detect any faults in its given fault domain. Different brake control modes in TSM have been compared, in which the ATP with high Priority control mode has a higher test cases number, but more time and memory consumption.