Abstract: Effectively testing safety-critical scenarios is an important means to improve security of cyber-physical systems.How to model safety critical scenarios so that the behavior of systems can be completely and precisely described,and how to effectively generate test cases so as to enhance the test coverage and reduce testing cost,are two key technical problems that must be solved in safety-critical scenarios’testing.Existing scenario modeling and test case generation techniques lack the support to describing and treating the important features of cyber-physical systems,thus they can’t generate test cases satisfying the testing requirements of the safety critical scenarios.We studied modeling and test case generation methods to safety critical scenarios in cyber-physical systems.A method that satisfies the requirement for modeling safety-critical scenarios by extending UML activity diagram with external event driven mechanism and timeliness characterizing mechanism was proposed.Then based on the scenario models,we studied a method to automatically generate test cases.

Key words: Cyber-physical systems,Safety-critical scenarios,Automatic testcase generation