The Test Driver is the "main program" that controls the test. Here is a simple example of a driver that will test the sine function from the standard C library:
It is somewhat strange that while usability testing has been around for over two decades, it is still shrouded by a number of myths and misconceptions. Over the years usability testing, a very important part of software development, has become much simpler, faster and cheaper - there's really no good reason to NOT do usability testing.