> The first is manual testing. If you haven’t seen the code do the right thing yourself, that code doesn’t work. If it does turn out to work, that’s honestly just pure chance.

Depending on exactly what the author meant here, I disagree. Our first and default tool should be some form of lightweight automated testing. It's explicit (serves a form of spec and docs how to use the software), it's repeatable (manual testing is done once and it's result is invalidated moments later), and it's cost per minute of effort is more or less the same (most companies have the engineers do the tests, they are expensive).

Yes. There will be exceptions and exceptional cases. This author is not talking about exceptions and neither am I. They're not an interesting addition to this conversation.