Conformance Testing for non Deterministic Timed Pushdown Automata with Deadlines

This paper is about conformance testing of non-deterministic timed pushdown automata (TPAIO), with urgency modelled as deadlines put on the transitions. The deadlines impose time progress conditions (TPC) on the locations of the TPAIO. In addition to detecting non conform or out of the time limits outputs of an implementation, our tests also detect TPC violations. Our method proceeds by a one-clock determinization of the TPAIO, followed by the computation of a reachability automaton aiming at covering the reachable transitions and locations of the TPAIO, w.r.t. the stack constraints. Each RA transition records an execution path of the TPAIO. To get the tests, we add to these execution paths the fail verdicts issued from the determinization. Their ability to detect non conform implementation is assessed by mutation: altered implementations are automatically generated from a specification by application of some mutation operators that we define.