def test_change_public_access_directory(self):
        """Test that directories can be made public if explicitly requested."""
        a_dir = self.vgw.make_tree(self.root.id, '/x')
        # It has no public ID
        self.assertIsNone(a_dir.public_uuid)
        # It now has a public ID
        self.assertIsNotNone(
            self.vgw.change_public_access(a_dir.id, True, True).public_uuid)