In this paper we discuss the experiences gained in conducting a simple testing experiment. The goal of this experiment is to apply the abstract, formal testing framework [8] in a practical setting, and to indicate the critical aspects in its application to realistic testing situations. For that purpose a formal description of the system under test (SUT) is made from which tests are systematically derived. These tests are interpreted and executed by a tester against concrete implementations, thereby giving an indication about the correctness of these implementations
