I've added those expectations, and cleaned up the flow a bit. There's an unfortunate situation having to do with the fact that POP3 doesn't set USES_CONN, which means that POP3 doesn't use th_main's help_expect_connection stuff. Long story short, POP3 could use a pass to clean up that logging and allow us to have parity between the implementations at test time.

I added a comment and some exceptions for the POP3 case here; I don't think it makes sense to completely revamp that in this PR, but it's probably worth creating a tracking bug and addressing that independently.