I agree, this is something that absolutely should be taught early on in programming classes. One side note, which a commenter pointed out on the actual post, is

I agree, this is something that absolutely should be taught early on in programming classes. One side note, which a commenter pointed out on the actual post, is whether or not someone who is teaching programming will be viable to teach testing. Regardless, it is something I'd like to see emphasized a bit more in all the code.org hype.