It is a fact that "succesful testing does not prove the abscence of bugs, it only proves the abscence of known bugs", even you, Donald, can not disprove that.

Does that mean the we should not test? of course not.

It means that if your method of design relies on testing you should find another career.

We see things like "I did not use a RS232 transciever and tested it, so it is proven that the MAX232(equivalent) is not necessary" and that, as most of us know, is fried baloney.

You can not use "testing" to verify a design, but you can use testing to verify that your implementation of a well thought out design does not have any blatant implementation errors.

If something is well designed before it is implememnted the likelyhood is that any error will be blatant and thus seen. If you do not design before testing the likelyhood is that you will have an error that will show up when some tolerance or confluence occur.

Erik