This commit adds a tiny unit test for the new `shlex` based
os-release parsing and tweaks the error message in a small
and non-functional way (just because it's slightly nicer
for a user). The test checks for three keys NAME which is
quoted with `"`, ID which is not quoted and OSTREE_VERSION
which is quoted with `'`.
We want to extend our base-class to support extensions to
unittest.TestCase, so make sure we inherit from it.
Adjust all callers to no longer inherit from TestCase, since this is now
done automatically by TestBase.
We use comments in all other tests, rather than doc-strings. Convert the
os-release test to do the same. If we wanted doc-strings, we can convert
all tests over. This commit just tries to keep the tests in-sync.
Note that doc-strings cause `unittest` to print the doc-strings to
stdout during test-execution, making it overly verbose (especially for
multiline docs). By converting it to comments, this behavior is
suppressed.
Use the new `locate_test_data()` helper to get access to test-data.
Guard the test with `have_test_data()` to skip it in case test-data
access is not available.
