> ensure the integrity of the program through revision Yes, that is what I am thinking: each step is like sending the signal through a noisy channel (that also

> ensure the integrity of the program through revision Yes, that is what I am thinking: each step is like sending the signal through a noisy channel (that also does some transforming -- it is not an exact analogy). But testing doesn't seem to be carefully designed to address the particular kinds of 'noise'/mistakes that humans make.