Section: New Results

Model-based Testing an Interactive Music System

We have been pursuing our studies on the application of model-based timed testing techniques to the interactive music system (IMS) Antescofo, in the context of the Phd of Clément Poncelet and in relation with the developments presented in Section  6.3 .

Several formal methods have been developed for automatic conformance testing of critical embedded software, with the execution of a real implementation under test (IUT, or black-box) in a testing framework, where carefully selected inputs are sent to the IUT and then the outputs are observed and analyzed. In conformance model-based testing (MBT), the input and corresponding expected outputs are generated according to formal models of the IUT and the environment. The case of IMS presents important originalities compared to other applications of MBT to realtime systems. On the one hand, the time model of IMS comprises several time units, including the wall clock time, measured in seconds, and the time of music scores, measured in number of beats relatively to a tempo. This situation raises several new problems for the generation of test suites and their execution. On the other hand, we can reasonably assume that a given mixed score of Antescofo specifies completely the expected timed behavior of the IMS, and compile automatically the given score into a formal model of the IUT’s expected behavior, using an intermediate representation. This give a fully automatic test method, which is in contrast with other approaches which generally require experts to write the specification manually.

We have developed online and offline approches to MBT for Antescofo. The offline approach relies on tools of the Uppaal suite  [38] , [37] , using a translation of our models into timed automata. These results have been presented during the 30th ACM/SIGAPP Symposium On Applied Computing, track Software Verification and Testing [21] and an article describing this approach has been accepted for publication in the Journal of New Music Research. The online approach is based on a new virtual machine executing the models of score in intermediate representation (see Section  6.3 ).