Dynamic redundancy identification in automatic test generation

Test generation for combinational circuits, an NP-complete problem, shows its worst-case behavior while trying to generate tests for redundant faults and failing after an exhaustive search. The performance of an automatic test generator can be significantly improved by identifying redundancy via simple techniques which do not involve a search. The authors present a technique to identify redundant faults. This technique works dynamically during test generation, but is not based on a search process. It relies on test-covering relations among faults, which allow identification of addition redundant faults after the test generator fails to generate a test for a target fault. This technique has been implemented in AT&T´s Testpilot test generation system and has shown a reduction of up to 32% in the number of backtracks in test generation runs