> I think that's difficult to implement, as the files are not there
> anymore when the check is made (only the tarfile); somebody correct
> me if I'm wrong.

The files are created during setup, and I think exist through the
duration of the test, only being removed during tearDown (via
TempDirManager mixin) - otherwise this test couldn't be creating two
separate archives from the same sources.

Worst case though, just have setup grab the test file ownership
information and hang onto it in general.  But I think this specific test
could also check filesystem ownership at any point in the test.