World Academic Union
With the invasive application of information system in society, software begins to take an important role in everyday life. Software testability is proposed to address the problem of increasing cost of test and the quality of software. Testability measure provides a quantified way to denote the testability of software. Many testability measure models are proposed to address the problem. By discussing the contradiction between domain testability and Domain Range Ratio (DRR), a new testability measure, semantic fault distance, is proposed. Its validity is discussed.