Featured Transition Systems (FTS) is a mathematical structure to represent the behaviour of software product line in a concise way. The combination of the well-known transition systems approach to formal behavioural modelling with feature expressions was pivotal to the design of efficient verification approaches. Such approaches indeed avoid to consider products’ behaviour independently, leading to often exponential savings. Building on this successful structure, we lay the foundations of model-based testing approach to SPLs. We define several FTS-aware coverage criteria and report on our experience combining FTS with usage-based testing for configurable websites.