Covers the validation matrix of the new --gpg-* / --ssh-signing-*
surface: mutual exclusion (across GPG/SSH groups and within the SSH
group between --ssh-signing-key-file and --ssh-signing-reuse-private-
key), alias resolution between --ssh-signing-password and
--ssh-signing-passphrase, the dependency checks (--ssh-signing-
password requires --ssh-signing-key-file; --ssh-signing-reuse-
private-key requires --private-key-file), and pre-flight key-parse
failures (malformed PEM, encrypted SSH key without passphrase, GPG
ring with wrong passphrase). Test keys are checked in so the test
does not depend on local ssh-keygen or gpg invocations at run time.
Signed-off-by: Hidde Beydals <hidde@hhh.computer>
Hidde Beydals