When the user knows the signer's key, we want "notmuch show" to be
able to verify the signature of an encrypted and signed message
regardless of whether we are using a stashed session key or not.
I wrote this test because I was surprised to see signature
verification failing when viewing some encrypted messages after
upgrading to GPGME 1.13.0-1 in debian experimental.
The added tests here all pass with GPGME 1.12.0, but the final test
fails with 1.13.0, due to some buggy updates to GPGME upstream: see
https://dev.gnupg.org/T3464 for more details.
While the bug needs to be fixed in GPGME, notmuch's test suite needs
to make sure that GMime is doing what we expect it to do; i was a bit
surprised that it hadn't caught the problem, hence this patch.
I've fixed this bug in debian experimental with gpgme 1.13.0-2, so the
tests should pass on any debian system. I've also fixed it in the
gpgme packages (1.13.0-2~ppa1) in the ubuntu xenial PPA
(ppa:notmuch/notmuch) that notmuch uses for Travis CI.
Signed-off-by: Daniel Kahn Gillmor <dkg@fifthhorseman.net>
