From the video, it seems that all three agree that unit testing is not the right answer in every situation, and having unit tests that are highly coupled with implementation details is usually a bad idea.
If you start a Rails project, and follow the official guidelines about writing tests, at some point, after writing several hundred tests, your test suite will begin to take minutes. And most of that time is spent in setting up fixtures and ActiveRecord db calls. This simply is not scalable.
I don’t know what the best solution is, but Corey Haines has a decent one here: