these great doers who shape the world don't seem to like unit testing. i'll follow them, at least because they are smarter than those bloggers.
but do listen to their advice and do your own thinking.
The point is not to write tests because Norvig doesn't, or equally, to write tests because "Uncle" Bob does.
Just think about what they say before copying them blindly especially when you encounter methodology vendors, "naked men who sell you their shirt" as it were, and not succumb to the latest snake oil nostrum just because its vendors have loud voices.