Docker-systemctl-replacement

the dot-zero release had over 90% line coverage already.

Bugs and Features

With release 1.0 to also know about reordering of services, the
systemctl.py replacement script was about feature complete. This
was in 2017. After that time the changes are tracked using the GitHub
issue list as well as mentioning the changes in the release notes
attached to the git tags / github releases.

Be aware that the systemctl replacement does not want to mimic the
systemd behaviour in all detail. There had been always the expectation
that at some point the docker cluster managers will be able to
run containers with some systemd emulation themselves. So essentially,
the systemctl.py script would become obsolete soon - however, it took
very long. While rkt was quick, but it was podman in 2019 to be able
to attract developers with their systemd emulation. The real change
came somewhen in 2022 when almost all vendors provided upstream docker
images with full support and mostly even upstream helm charts for
deployment in a Kubernetes-like cluster.

So let's close this history wrapup with a final remark: most
Linux distributions are run by systemd at the time of writing
this text. But systemd is a flawed solution - not only because
it breaks the Unix Philosophy of "Do One Thing and Do It Well".
There are many quirks in the service descriptors and the whole
functionality is badly documented - we're all just lucky that
it works at all. SystemD is a bug itself.

Testsuite

In the first release only a "Maketests" file did exist, covering
as much as three Dockerfiles. As it was inconvenient to switch
back and forth to the other project, some Ansible code was copied
over for testing in release 0.5. With more and more dockerfiles,
that became the testsuite for quite a while.

It took to release 0.7 that a testsuite.py file exists but that was
only a wrapper to run the old dockerfile builds and the old ansible
scripts. Basically, the old test cases did get a number! Using
experiences from another project, the unittest.main loop is not
used but a different cli where one can run a test case by the prefix
of its method name - for example `testsuite.py test_6001`. The old
file "Maketests" was replaced by that.

For release 0.8 the systemctl script was enhanced with an extra
option "--root=path" to be able to test functionality without
starting a docker container (something that was required before).
For release 0.9 the testsuite.py was enhanced to use "coverage2"
when running sytemctl.py so that one could know how many testcases
were still needed. This was done with the intention that an upcoming