Abstract. Pervasive systems, and domotics in particular, is an application area where heterogeneity is the norm, with thousands of autonomous heterogeneous devices live together and need to interoperate. One of the greatest difficulties in developing middleware for smart homes is that this kind of systems are extremely difficult to test and verify. We propose to reduce the testing costs by replacing actual home services with virtual stubs behaving as if they were actual hardware installed somewhere in the house and, most importantly, to visualize the behaviour of the home to give the user the impression and feedback of being in a real home.