In this paper a graph model and a method to construct robust (for the first
time in open literature) as well as non-robust two-pattern tests for one-d
imensional iterative logic arrays (ILAs) are presented. Exploring the graph
structure we can find two-pattern tests that can be applied with a constan
t or linear number of test vectors to all the ILA cells. Such tests are sub
sequently characterized as robust or non-robust two-pattern tests.