diff --git a/unittests/test_identified_cache.py b/unittests/test_identified_cache.py
index 33add97d4309d87705144ec5331366d0bcd05541..3809f5e45a063981f99f3370d4bdc0004c376193 100644
--- a/unittests/test_identified_cache.py
+++ b/unittests/test_identified_cache.py
@@ -53,6 +53,8 @@ def test_create_hash():
         db.Record("A")
         .add_parent("B")
         .add_property('a', [db.Record(id=12), 11])) == "P<B>N<A>a:[12, 11]")
+    assert (_create_hashable_string(db.Record().add_parent("B").add_property('a', [db.Record()]))
+            != _create_hashable_string(db.Record().add_parent("B").add_property('a', [db.Record()])))
 
 
 def test_IdentifiedCache():