Add offset when getting single item. Fixes #1271

wagtail/wagtailsearch/backends/base.py

@@ -155,8 +155,8 @@ class BaseSearchResults(object):
             if self._results_cache is not None:
                 return self._results_cache[key]
 
-            new.start = key
-            new.stop = key + 1
+            new.start = self.start + key
+            new.stop = self.start + key + 1
             return list(new)[0]
 
     def __iter__(self):

wagtail/wagtailsearch/tests/test_elasticsearch_backend.py

@@ -454,7 +454,6 @@ class TestElasticSearchResults(TestCase):
             size=10
         )
 
-    @unittest.expectedFailure # 1271
     @mock.patch('elasticsearch.Elasticsearch.search')
     def test_slice_results_and_get_item(self, search):
         # Need to return something to prevent index error