'Test that the xblocks data is persisted correctly with display_name=None.'

def test_update_xblocks_cache_with_display_name_none(self):

    block_with_display_name_none = ItemFactory.create(parent_location=self.sequential_2.location, category='vertical', display_name=None)
    _update_xblocks_cache(self.course.id)
    self.course_expected_cache_data.update({block_with_display_name_none.location: [[self.course.location, self.chapter_1.location, self.sequential_2.location]]})
    for (usage_key, __) in self.course_expected_cache_data.items():
        xblock_cache = XBlockCache.objects.get(usage_key=usage_key)
        for (path_index, path) in enumerate(xblock_cache.paths):
            for (path_item_index, path_item) in enumerate(path):
                self.assertEqual(path_item.usage_key, self.course_expected_cache_data[usage_key][path_index][(path_item_index + 1)])
