Auto-detect systemd-sysusers(8) in tests

[dmnks]

Since commit 2bdd7d7, we no longer test the systemd-sysusers(8) implementation shipped by systemd. This also minimizes the local test tree (e.g. mktree.fedora) quite a bit since we no longer have to pull in the whole of systemd.

However, in the CI (i.e. mktree.podman), we might, just to have that use case covered. We can do that simply by detecting the presence of /usr/bin/systemd-sysusers in the respective test in rpmi.at (or perhaps in atlocal?) and using that if present.

[pmatilai]

The reason I'm asking you to triage your own ticket 😄 is: did this situation change with the recent test-suite oci image stuff?

[dmnks]

Actually, this didn't change much with the full move to OCI images. However, systemd-sysusers is installed into the image which means we can trivially use it in the test. I'm thinking we should probably just enhance the current test to run twice, setting %__systemd_sysusers to @__SYSTEMD_SYSUSERS@ the second time. Or just duplicate the test. In any case, Todo material...