Raluca Lefticaru and Anthony Simons were invited to present the Broker@Cloud work on the verification and testing of cloud services at the quarterly plenary meeting of the EU FP7 ProWess consortium, on Tuesday 23 September 2014. ProWess is investigating the use of property-based random testing for Erlang systems. The Broker@Cloud visitors presented their complementary work on model-based testing from EFSMs. The meeting was held in the pretty Derbyshire village of Hope, at the Losehill Hotel. Raluca presented the theory of Stream X-Machine (SXM) based testing and introduced the Sheffield verification and testing tool set. Tony gave a short presentation and live demonstration, showing how the tool set copes with systems that do not necessarily satisfy all the SXM testing assumptions - in other words, the tools innovate by compensating for missing testability properties in the system-under-test.
Highlights of the joint meeting included stimulating discussions with Professors Simon Thompson (University of Kent) and John Hughes (Chalmers University) on the similarities and differences between property-based and model-based testing. The ProWess folk were more interested in specific fault-isolation in long sequences, whereas Broker@Cloud is interested in conformance testing. The former lends itself to random testing, where the latter requires deterministic test generation. Attendees were also able to profit from the local countryside, walking from Losehill to Mam Tor and back, along the ridge between the Hope and Edale valleys. The day concluded with dinner and discussions at the hotel.