Highly Configurable Systems (HCS) aim at being easily modified and adapted to end-users needs or to their environment. When they span over a single domain, they are often called Product Lines (PL). Adaptation is possible by systematically reusing software components and explicitly dealing with variability among those components. After an initial investment, it becomes possible to drastically reduce development costs of new, envisaged products. However, ensuring the quality of such large systems is a new challenge: the configuration number grows exponentially with the options/variants number. This project aims at enhancing HCS through testing: we will define
new metrics suited to HCS, and will propose new methods for selecting non-regression tests and
analysing test smells.