Control strategies for off-line testing of timed systems

Partial observability and controllability are two well-known issues in test-case synthesis for interactive systems. We address the problem of partial control in the synthesis of test cases from timed-automata specifications. Building on the tioco timed testing framework, we extend a previous game inte rpretation of the test-synthesis problem from the untimed to the timed setting. This approach is based on a generalization of strategies to states beyond the winning set, by identifying where the control is lost by the tester and what it can precisely control. We exhibit strategies of a game that tries to minimize both control losses and distance to the satisfaction of a test purpose, and prove they are winning under some fairness assumptions. This entails that when turning those strategies into test cases, we get properties such as soundness and exhaustiveness of the test synthesis method.