Due to the fast enlargement and complexity of systems used among telecommunication companies, the need for automatically testing has grown. The changeable nature of these systems makes implementation of automated testing to a difficult task. Finding an automated testing technique that is suitable for these types of systems is the subject of this thesis and several different types of scripting techniques has been considered. To be able to conduct this, an industrial case study is used; which shows how scripting techniques are affected by different types of changeability occurring in a system. / Marjaana Tienaho E-mail: Marjaana_tienaho@spray.se Jesús Barrio E-mail: jesus_barrio@hotmail.com E-mail: jesus_barrio@hotmail.com