1. One or more computer-readable storage devices or memory storing computer-readable instructions that when executed, cause a computer to perform a method, the method comprising: transforming an original description of a circuit under verification by adding a description of circuitry to inject effects of metastability into the circuit under verification, resulting in a transformed description, wherein said circuit under verification comprises one or more signals crossing between two clock domains; and analyzing the transformed description to determine a stimulus sequence for the transformed description to violate a pre-determined assertion.