TST: added a test of a duplicated property

unittests/test_sync_node.py

@@ -117,6 +117,11 @@ def test_sync_node():
         assert p in sn_a.parents
     for p in rec_a.properties + rec_b.properties:
         assert p in sn_a.properties
+    # Check for duplicated property:
+    ps = [p for p in sn_a.properties if p.name == "a"]
+    assert len(ps) == 2
+    assert ps[0].value == "a"
+    assert ps[1].value == "a"
 
     # test information in exported entity
     export = sn_a.export_entity()