! interimap --debug || error

# double check the presence of 'STARTTLS' in the preauth capability list
grep -oE -m1 '^remote: S: \* OK \[CAPABILITY IMAP4rev1( [^]]*)? AUTH=[^]]*\]' <"$STDERR" >"$TMPDIR/capability"

sed -ri 's/^remote: S: \* OK \[CAPABILITY (.*)\]$/\1/' "$TMPDIR/capability"
tr " " "\\n" <"$TMPDIR/capability" >"$TMPDIR/capabilities"
  grep -Fx "IMAP4rev1" <"$TMPDIR/capabilities" || error
! grep -Fx "STARTTLS"  <"$TMPDIR/capabilities" || error

# make sure we didn't send any credentials
grep -Fx "remote: ERROR: Server did not advertise STARTTLS capability." <"$STDERR" || error
! grep -E "^remote: C: .* (AUTHENTICATE|LOGIN) "                        <"$STDERR" || error

# vim: set filetype=bash :