In one embodiment, a system and method pertain to identifying an output signal having indeterminate timing, creating an expectation for a signal change associated with the output signal, and adding the expectation to an ordered list of expectations for the output signal. In another embodiment, a system and method pertain to detecting a signal change, identifying a vector associated with the signal in which the change occurred, examining pending expectations of the vector until a mature expectation is identified, comparing an expected value contained in the mature expectation with the detected signal change, and reporting an error if the expected value does not match the detected signal change.