Comment 1 for bug 1589174

Hi,
sorry - I missed to test in that kind of isolated environments on the merge.

Thanks for faking the get_release, as you have seen in test_handler_apt_configure_sources_list.py I already cared about being release independent (but only thought on release independence, not unavailability of lsb_release back then).

To summarize what we have to cover now:
1. getkeybyid will only work in network enabled environments that can reach keyserver.ubuntu.com (Note that I already avoided to use non .ubuntu.com addresses in the test)
=> We need to restore (undo the mocking of getkeybyid) in a way that it will work in network capable environments, but gracefully skip in others.

2. The capability to make the tests independent to a underlying ubuntu/debian environment. That in my opinion is a bit special, as all of the feature that it tests is debian/ubuntu special (apt / apt-key)
=> still it should detect and fail gracefully in those cases.

First I had to try recreate without bothering LP each time, I chose - if I go into it I can make it better anyway - and added a test for a third party keyserver.
Using that with a bad KS intentionally I had a test for failing network.

Also this was the right time to re-include the improvements we made when thinking through the same thing on the curtin side of things.