Automating Integration Testing of Large-Scale Publish/Subscribe Systems

Publish/subscribe systems are event-based systems separated into several components which publish and subscribe events that correspond to data types. Testing each component individually is not sufficient for testing the whole system; it also requires testing the integration of those components together. In this chapter, first we identify the specificities and difficulties of integration testing of publish/subscribe systems. Afterwards, two different and complementary techniques to test the integration are presented. One is based on the random generation of a high number of event sequences and on generic oracles, in order to find a malfunctioning state of the system. The second one uses a limited number of predefined data-flows which must respect a precise behaviour, implementable with the same mechanism as unit-testing. As event-based systems are well fitted for runtime modification, the particularities of runtime testing are also introduced, and the usage in the context of integration testing is detailed. A case study presents an example of integration testing on a small system inspired by the systems used in the maritime safety and security domain.