Add an option to use scan helper without search_type=scan, use with caution

Fixes #160

test_elasticsearch/test_server/test_helpers.py

@@ -138,6 +138,19 @@ class TestBulk(ElasticsearchTestCase):
 
 
 class TestScan(ElasticsearchTestCase):
+    def test_order_can_be_preserved(self):
+        bulk = []
+        for x in range(100):
+            bulk.append({"index": {"_index": "test_index", "_type": "answers", "_id": x}})
+            bulk.append({"answer": x, "correct": x == 42})
+        self.client.bulk(bulk, refresh=True)
+
+        docs = list(helpers.scan(self.client, index="test_index", doc_type="answers", size=2, query={"sort": ["answer"]}, preserve_order=True))
+
+        self.assertEquals(100, len(docs))
+        self.assertEquals(list(map(str, range(100))), list(d['_id'] for d in docs))
+        self.assertEquals(list(range(100)), list(d['_source']['answer'] for d in docs))
+
     def test_all_documents_are_read(self):
         bulk = []
         for x in range(100):