Conformance Testing of Preemptive Real-Time Systems

Abstract

The paper presents an approach for model-based black-box conformance testing of preemptive real-time systems using Labeled Prioritized Time Petri Nets with Stopwatches (LPrSwTPN). These models not only specify system/environment interactions and time constraints. They further enable modelling of suspend/resume operations in real-time systems. The test specification used to generate test primitives, to check the correctness of system responses and to draw test verdicts is an LPrSwTPN made up of two concurrent sub-nets that respectively specify the system under test and its environment. The algorithms used in the TINA model analyzer have been extended to support concurrent composed subnets. Relativized stopwatch timed input/output conformance serves as the notion of implementation correctness, essentially timed trace inclusion taking environment assumptions into account. Assuming the modelled systems are non deterministic and partially observable, the paper proposes a test generation and execution algorithm which is based on symbolic techniques and implements an online testing policy and outputs test results for the (part of the) selected environment.