1. A method comprising: providing a waveform database, the database corresponding to several integrated circuit waveforms that each change in relation to a common period of time; applying a first assertion to a selected one of the integrated circuit waveforms with a processing device to test behavior of the first assertion; evaluating the first assertion based on the applying; and in response to the evaluating, modifying the first assertion to provide a second assertion to test the behavior of an integrated circuit design model.