Safe Fault Collapsing Based on Dominance Relations

For fault models with large numbers of faults, such as bridging faults, fault collapsing based on dominance relations can be effective in reducing the test generation time by reducing the number of target faults. When dominance relations are used for fault collapsing, a fault f_j is excluded from the set of target faults F if it dominates a fault f_i in F. However, if f_i remains undetected after test generation, f_j may remain undetected as well. We define safe fault collapsing to address this issue. For safe fault collapsing with a parameter s, f_j is excluded from the set of target faults F only if f_j dominates at least s faults f_i1, f_i2, hellip ,f _is in F. In this way, if any of the s faults dominated by f_j is detected, f_j will be detected as well. A higher value of s increases the likelihood of detecting f_j without targeting it. We describe a procedure for computing safe collapsed fault sets, and present experimental results of test generation for four-way bridging faults.