Start at about 23 min. Key phrase at about 29 min.
I completely agree with, "we right tests because we don't
understand our code." We don't want to understand all the code,
we also couldn't possibly achieve perfect understanding anyway,
so let us make the burden of transferring that knowledge easier
by having tests which catch mistakes.
I think his school analogy is wrong. TDD is more like teachers
writing a test to define what a successful teaching would be,
then developing a course which produces those results. Then you
administer the test to make sure your teaching fulfilled the
requirement. Oh that is exactly what we do.
