Combinatorial testing and model‐based testing

This issue contains two papers. The first paper focuses on combinatorial testing and the second one focuses on model-based testing. The first paper, ‘Combinatorial methods for testing Internet of Things smart home systems’ by Bernhard Garn, Dominik-Philip Schreiber, Dimitris E. Simos, Rick Kuhn, Jeff Voas, and Raghu Kacker, presents an approach for applying combinatorial testing (CT) to the internal configuration and functionality of Internet of Things (IoT) home automation hub systems. The authors first create an input parameter model of an IoT home automation hub system for use with test generation strategies of combinatorial testing and then propose an automated test execution framework and two test oracles for evaluation purposes. The proposed approach makes use of the appropriately formulated model of the hub and generates test sets derived from this model satisfying certain combinatorial coverage conditions. The authors conduct an evaluation of the proposed approach on a real-world IoT system. The evaluation results show that the proposed approach reveals multiple errors in the devices under test, and all approaches under comparison perform nearly equally well (recommended by W. K. Chan). The second paper, ‘Effective grey-box testing with partial FSM models’ by Robert Sachtleben and Jan Peleska, explores the problem of testing from a finite state machine (FSM) and considers the scenario in which an input can be enabled in some states and disabled in other states. There is already a body of work on testing from FSMs in which inputs are not always defined (partial FSMs), but such work typically allows the system under test (SUT) to be such that some inputs are defined in a state of the SUT but are not defined in the corresponding state of the specification FSM (the SUT can be ‘more’ defined). The paper introduces a conformance relation, called strong reduction, that requires that exactly the same inputs are defined in the specification and the SUT. A new test generation technique is given for strong reduction, with this returning test suites that are complete: a test suite is guaranteed to fail if the SUT is faulty and also satisfies certain conditions that place an upper bound on the number of states of the SUT. The overall approach also requires that the tester can determine which inputs are enabled in the current state of the SUT and so testing is grey-box (recommended by Helene Waeselynck).