* known_hosts: support --diff
* known_hosts: support --diff also without --check
* Add unit tests and fix incorrect diff in one corner case
Tests are good!
* Refactor for readability
* Python 3 compat
* More Python 3 compat
* Add an integration test for known_hosts
* Handle ssh-keygen -HF returning non-zero exit code
AFAICT this is a bug in ssh-keygen in some newer OpenSSH versions
(>= 6.4 probably; see commit dd9d5cc670):
when you invoke ssh-keygen with -H and -F <host> options, it always
returns exit code 1. This is because in ssh-keygen.c there's a function
do_known_hosts() which calls
exit (find_host && !ctx.found_key);
at the end, and find_host is 1 (because we passed -F on the command line),
but ctx.found_key is always 0. Why is found_key always 0? Because the
callback passed to hostkeys_foreach(), which is known_hosts_hash(),
never bothers to set found_key to 1.
* This test does not need root
* Avoid ssh-ed25519 keys in sample known_hosts file
Older versions of OpenSSH do not like them and ssh-keygen -HF
aborts with an error when it sees such keys:
line 5 invalid key: example.net...
/root/ansible_testing/known_hosts is not a valid known_hosts file.
* Fix Python 3 errors
Specifically, the default mode of tempfile.NamedTemporaryFile is 'w+b',
which means Python 3 wants us to write bytes objects to it -- but the
keys we have are all unicode strings.
