diff --git a/unittests/test_sync_graph.py b/unittests/test_sync_graph.py
index 5ea2bee7e128c1c6234958710e48a720fe225f01..b3dc3a9b4d0c2893f375ea257f50a45d73a9ea7c 100644
--- a/unittests/test_sync_graph.py
+++ b/unittests/test_sync_graph.py
@@ -23,13 +23,16 @@ from unittest.mock import MagicMock, Mock, patch
 
 import linkahead as db
 import pytest
-from caoscrawler.exceptions import ImpossibleMergeError, MissingIdentifyingProperty
+from test_crawler import basic_retrieve_by_name_mock_up, mock_get_entity_by
+
+from caoscrawler.exceptions import (ImpossibleMergeError,
+                                    MissingIdentifyingProperty)
 from caoscrawler.identifiable import Identifiable
 from caoscrawler.identifiable_adapters import CaosDBIdentifiableAdapter
 from caoscrawler.sync_graph import SyncGraph
 from caoscrawler.sync_node import SyncNode, parent_in_list, property_in_list
 
-from test_crawler import basic_retrieve_by_name_mock_up, mock_get_entity_by
+from itertools import product
 
 
 @pytest.fixture
@@ -66,7 +69,7 @@ def test_create_flat_list():
     assert b in flat
     c = db.Record()
     c.add_property(name="a", value=a)
-    # This would caus recursion if it is not dealt with properly.
+    # This would cause a recursion error if it is not dealt with properly.
     a.add_property(name="c", value=c)
     flat = SyncGraph._create_flat_list([c])
     assert len(flat) == 3
@@ -82,41 +85,33 @@ def test_create_reference_mapping():
                  db.RecordType().add_property("a"))
     ses = [a, b]
 
+    mappings = SyncGraph._create_reference_mapping(ses)
+    # test initialization
+    for index, mapping in product((0, 1), mappings):
+        assert id(ses[index]) in mapping
+
     (forward_references, backward_references, forward_id_references,
      backward_id_references, forward_id_referenced_by,
-     backward_id_referenced_by) = SyncGraph._create_reference_mapping(ses)
-    # test initialization
-    assert id(ses[0]) in forward_references
-    assert id(ses[1]) in forward_references
-    assert id(ses[0]) in backward_references
-    assert id(ses[1]) in backward_references
-    assert id(ses[0]) in forward_id_references
-    assert id(ses[1]) in forward_id_references
-    assert id(ses[0]) in backward_id_references
-    assert id(ses[1]) in backward_id_references
-    assert id(ses[0]) in forward_id_referenced_by
-    assert id(ses[1]) in forward_id_referenced_by
-    assert id(ses[0]) in backward_id_referenced_by
-    assert id(ses[1]) in backward_id_referenced_by
+     backward_id_referenced_by) = mappings
 
     # a has no ref
-    assert len(forward_references[id(ses[0])]) == 0
-    assert backward_references[id(ses[0])] == set([ses[1]])
+    assert len(forward_references[id(a)]) == 0
+    assert backward_references[id(a)] == set([b])
     # b does
-    assert forward_references[id(ses[1])] == set([ses[0]])
-    assert backward_references[id(ses[1])] == set()
+    assert forward_references[id(b)] == set([a])
+    assert backward_references[id(b)] == set()
     # a has no identifying reference
-    assert forward_id_references[id(ses[0])] == set()
-    assert backward_references[id(ses[0])] == set([ses[1]])
+    assert forward_id_references[id(a)] == set()
+    assert backward_id_references[id(a)] == set([b])
     # b has an identifying reference
-    assert forward_id_references[id(ses[1])] == set([ses[0]])
-    assert backward_references[id(ses[1])] == set()
+    assert forward_id_references[id(b)] == set([a])
+    assert backward_id_references[id(b)] == set()
     # a has an identifying back reference
-    assert forward_id_referenced_by[id(ses[0])] == set()
-    assert backward_id_referenced_by[id(ses[0])] == set([ses[1]])
+    assert forward_id_referenced_by[id(a)] == set()
+    assert backward_id_referenced_by[id(a)] == set([b])
     # b does not
-    assert forward_id_referenced_by[id(ses[1])] == set([ses[0]])
-    assert backward_id_referenced_by[id(ses[1])] == set()
+    assert forward_id_referenced_by[id(b)] == set([a])
+    assert backward_id_referenced_by[id(b)] == set()
 
 
 @patch("caoscrawler.sync_graph.cached_get_entity_by",