Theofanis Vassiliou-Gioles studied electrical engineering at the TU Berlin before moving to GMD FOKUS in 1998 and later to Fraunhofer FOKUS. His research focus there was the testing of telecommunication systems in particular and building on the finding for distributed software systems in general. This work was reinforced by the founding of the spin-off Testing Technologies, which Theo Vassiliou co-founded and managed for 16 years. His technical focus during this period was the applicability of the developed methods in new technology fields, like energy, aviation and automotive industry. As a Ph.D. student in Research Group 20 he is dedicated to test questions in the area of development and operation of micro-service-based software systems.