"Scaffolding Tests" are Kent Beck's term for ephemeral tests which serve a purpose, but are later removed once they are no longer necessary.
At 39 minutes he talks about deleting tests (but does not use Kent Beck's scaffolding name)
JESSICA: Exactly. Do you ever go back and delete the ones that were really only useful to drive the design?
NOEL: Sometimes. Again, people get nervous when you start deleting tests. Another thing that's valuable is to just look at, RSpec has a profiler that will just tell you where the slow test, what the slowest tests are. And sometimes it's just valuable to look at the slowest, the very slowest tests and try and figure out what's going on and whether the test is still valuable, why it's slow, and whether it needs to be… invariably, or almost certainly in a Rails application it's going to be slow because it's creating a lot of data. And then the question is just like, is there a better way to do this? So, that can be a valuable thing to do sometimes.
At 35: SAM: I was saying there's a really interesting idea, the idea that you can write a test and then throw it away. It took me so long to get comfortable with that. (#)
I then delete the acceptance test from the project. I don't need it anymore. It was a troubleshooting tool, and it did its job. I have another lower-level test which covers the specific change I made. (#)