It is of paramount importance that a test cost reduction strategy is incorporated in the design for testability philosophy of an IC. The reliance of the traditional s fault model is inadequate in such a strategy. All studies agree that this model does not reflect the physical failures of real devices, principally because such failures do not exhibit a 1:1 mapping onto the logic domain. The author(s) have proposed the adoption of a non-tactile intelligent novel method which processes information obtained from a scanning laser beam reflected from a surface profile, such that shorts and opens in both metallic and non- metallic domains can be detected, located, and logged where necessary. Scanning may be of a raster nature over the surface, or follow a suitable path search along layouts. The latter search type has been simulated in PROLOG using breadth-first (BRFS), Euler (ES), and neighbor-first (NFS) searches. It is suggested that by creating and modifying an acquired-knowledge database (AKDB), according to defect occurrence, it is also possible to search those regions where defects may be present in order of decreasing probability, according to a prediction database (PDB). Thus a useful library of the distribution of defect density statistics should be created by virtue of this proposal. In this paper results of search simulations and discussion of the AKDB implications are included. The paper concludes that within limits, the Euler search is superior. Such a topological approach to the testing problem offers a test structure for exploitation which is technology independent, relatively fast, adaptable to parallel processing, and may be interfaced with machine vision systems.