Most of the integration tests have been made to not write to /usr
but some genuinely need to do so.
Because mkosi creates images with a read-only /usr
it is not normally writeable.
By mounting an overlayfs with /usr as the lower dir
and upper and working dirs in /var tests may write to /usr.
Quoting https://github.com/systemd/systemd/pull/25050#discussion_r998721845:
This part seems to be quite racy, at least in the C8S job:
[ 1767.520856] H testsuite-15.sh[35]: *** test transient slice drop-ins
[ 1767.520856] H testsuite-15.sh[35]: + mkdir -p /etc/systemd/system/slice.d
[ 1767.522480] H testsuite-15.sh[35]: + mkdir -p /etc/systemd/system/a-.slice.d
[ 1767.524992] H testsuite-15.sh[35]: + mkdir -p /etc/systemd/system/a-b-.slice.d
[ 1767.526799] H testsuite-15.sh[35]: + mkdir -p /etc/systemd/system/a-b-c.slice.d
[ 1767.528302] H testsuite-15.sh[35]: + echo -e '[Unit]\nDocumentation=man:drop1'
[ 1767.528434] H testsuite-15.sh[35]: + echo -e '[Unit]\nDocumentation=man:drop2'
[ 1767.528519] H testsuite-15.sh[35]: + echo -e '[Unit]\nDocumentation=man:drop3'
[ 1767.528595] H testsuite-15.sh[35]: + echo -e '[Unit]\nDocumentation=man:drop4'
[ 1767.528676] H testsuite-15.sh[35]: + systemctl cat a-b-c.slice
[ 1767.541321] H systemctl[1042]: No files found for a-b-c.slice.
[ 1767.542854] H systemd[1]: testsuite-15.service: Main process exited, code=exited, status=1/FAILURE
[ 1767.542995] H systemd[1]: testsuite-15.service: Failed with result 'exit-code'.
[ 1767.543360] H systemd[1]: Failed to start testsuite-15.service.
[ 1767.543542] H systemd[1]: testsuite-15.service: Consumed 1.586s CPU time.
[ 1767.543938] H systemd[1]: Reached target testsuite.target.
[ 1767.545737] H systemd[1]: Starting end.service...
We want to test four things:
- that the transient units are successfully started when drop-ins exist
- that the transient setings override the defaults
- the drop-ins override the transient settings (the same as for a normal unit)
- that things are the same before and after a reload
To make things more fun, we start and stop units in two different ways: via
systemctl and via a direct busctl invocation. This gives us a bit more coverage
of different code paths.
Slices are worth testing too, because they don't need a fragment path so they
behave slightly differently than service units. I'm making this a separate
patch from the actual tests that I wanted to add later because it's complex
enough on its own.
clear_services() is renamed to clear_units() and now takes a full
unit name including the suffix as an argument.
_clear_service() is renamed to clear_unit() and changed likewise.
create_service() didn't have the same underscore prefix, and I don't think
it's useful or needed for a local function, so it is removed.
No functional change.
Bash will generate a very nice message for us:
/tmp/ff.sh: line 1: SOMEVAR: parameter null or not set
Let's save some keystrokes by not replacing this with our own inferior
messages.
Sometimes the test would fail there, nondeterministically. I'm not sure why,
but relying on PID1 not caching the file is clearly very brittle. Let's instead
call daemon-reload.
