Abstract: An example method for determining test conditions for at-speed transition delay fault tests on semiconductor devices is provided and includes analyzing scan patterns for testing a circuit of a device-under-test (DUT), identifying paths in the circuit activated by the scan patterns, determining behavior of the paths at different test corners, generating a histogram for each scan pattern representing a distribution of paths exhibiting worst-case behavior at corresponding test corners, generating an ordered set of scan pattern-test corner combinations based on the histogram, selecting a threshold for the ordered scan pattern-test corner combinations based on quality metrics, generating an ordered test set including the ordered scan pattern-test corner combinations with the selected threshold, and feeding the ordered test set to a test instrument, the test instrument testing the DUT according to the ordered test set, the tests being performed at the test corners listed above the selected threshold.