Automating Mockup-Based Usability Testing on the Mobile Device

User interface usability is a very relevant aspect, especially for mobile applications. In this paper we propose a methodology for automating user interface usability testing in the early phases of the development process directly on the mobile device. Mockup interfaces are designed, then the way the designer interacts with the interface is compared with the way the end-user interacts with the same interface and the discrepancies between the two usage models are highlighted. The methodology is supported by a mobile tool named PlatoS, which captures a case of use of a mockup in terms of a sequence of actions. On the end-user side, PlatoS captures the user interaction with the mockups and performs the automatic identification of usability problems on the base of the log data. An example of evaluation of an eCommerce mobile prototypes is also presented.