This was something that was missing in #707.
Adding a new test to make sure the ephemeral feature flag from upstream
is set up correctly by the script.
The unit tests are simulating a run for entrypoint. It creates some
dummy config.sh and runsvc.sh and makes sure the logic behind
entrypoint.sh is correct.
Unfortunately the entrypoint.sh contains some sections that are not
mockable so I had to put some logic in there too.
Testing includes for now:
- the normal scenario
- the normal non-ephemeral scenario
- the configuration failure scenario
Also tested the entrypoint.sh on a real runner, still works as expected.