There is a growing interest for techniques and tools facilitating the testing of mobile systems. The movement of nodes is one of the relevant factors of context change in ubiquitous systems and a key challenge in the validation of context-aware applications. An approach is proposed to generate a testbed for service-oriented systems that takes into account a mobility model of the nodes of the network in which the accessed services are deployed. This testbed allows a tester to assess off-line the QoS properties of a service under test, by considering possible variations in the response of the interacting services due to node mobility.