Validation of mobile applications needs taking account of context (such network topology) and interactions between mobile nodes. Scenario-based approaches are well-suited to describe the behavior and interactions to observe in distributed systems. The difficulty to control accurately the execution context of such applications has led us to use passive testing. This paper presents a toolset which supports specification and verification of scenarios. A UML-based formal language, called TERMOS, has been implemented for specifying scenarios in mobile computing systems. These scenarios capture the key properties which are automatically checked on the traces, considering both the spatial configuration of nodes and their communication. We give an overview of the language design choices, its semantics and the implementation of the tool chain. The approach is demonstrated on a case study.