If the base directory already ends with '/' the test failed.
It failed because we added an extra '/' to make sure that '/foobar' is
not under '/foo', so ask '/foobar/'.startswith('/foo/').
Whoever when we have the base already start with '/' we might test:
'/foo/bar/'.startwith('/foo//'), and give a false negative. We
shouldn't have this case, because we normalized the path, but in the
case of the root directory ('/') even a normalized path ends with '/',
and thus when base='/' this function failed.
Some re-factoring was needed to make this base testable.
Chen Rotem Levy
9877ad5155