Add test for password authentication about fedora-coreos-config HOT 3 CLOSED

I was thinking we'd primarily want to test local login, but it probably wouldn't hurt to test SSH for people who want to enable that. For the latter, we could add an internal kola test that uses SSHAgent.NewPasswordClient().

That sudo command will check the password for the core user, not testuser. And since core is in the sudo group, we won't get a password prompt by default. echo password | setsid su - testuser should work.

(su falls back to stdin if there's no controlling terminal, and setsid ensures there isn't one.)

from fedora-coreos-config.

Add a test that provisions a user password via Ignition (replicating docs) and checks that the password works for local login.

This particular part might be a bit tricky if we want to test SSH with password. AFAIU we'd need the sshpass utility. Maybe just verifying via a local su - is enough?

from fedora-coreos-config.

something like: echo 'mypassword' | sudo --stdin -u testuser id

from fedora-coreos-config.