'Returns the HTML and resources required for the xblock at the specified UsageKey'

def _get_container_preview(self, usage_key, data=None):

    resp = self._get_preview(usage_key, data)
    self.assertEqual(resp.status_code, 200)
    resp_content = json.loads(resp.content)
    html = resp_content['html']
    self.assertTrue(html)
    resources = resp_content['resources']
    self.assertIsNotNone(resources)
    return (html, resources)
