Testing often accounts for more than 50% of the required e?ort during system development.Thechallengeforresearchistoreducethesecostsbyprovidingnew methods for the speci?cation and generation of high-quality tests. Experience has shown that the use of formal methods in testing represents a very important means for improving the testing process. Formal methods allow for the analysis andinterpretationofmodelsinarigorousandprecisemathematicalmanner.The use of formal methods is not restricted to system models only. Test models may...