Exhaustive and Pseudo-Exhaustive Testing

摘要

This chapter discusses an approach to test pattern generation for functional testing of combinational digital integrated circuits. The techniques to be presented apply all possible input patterns either to the entire circuit under test or to portions of the circuit under test. For some circuits, exhaustive testing is economically practical: all possible input combinations are applied to the entire circuit. An exhaustive test is a complete functional test and no assumptions about the internal structure of the circuit under test are required. When the number of inputs is so large that an exhaustive test is impractical, it is still possible to retain many of the advantages of exhaustive testing by using a pseudo-exhaustive test technique. Pseudo-exhaustive testing requires that some details of the internal circuit structure either be known or assumed. A disadvantage of exhaustive and pseudo-exhaustive testing is the size of the test sets: they can be substantially larger than minimum-length test sets. The major advantages of exhaustive and pseudo-exhaustive tests are the extremely high fault coverage, the generality of the fault model, and the absence of a requirement to do fault simulation. Another advantage of output function verification is the ease of generating the test set. Segmentation and determination of the corresponding test sets requires more computation.