diff --git a/unittests/test_sync_graph.py b/unittests/test_sync_graph.py
index 8dbceadb654caac88248e4fec83b4316c8c5abd0..e14c83461b1582d7eb430ccf8a4a889ac1a7e8f0 100644
--- a/unittests/test_sync_graph.py
+++ b/unittests/test_sync_graph.py
@@ -195,31 +195,31 @@ def test_merge_into_trivial(simple_adapter):
     # CHECK REFERENCE MAP (before merge):
     # c is referenced by a
     assert len(st.forward_references[id(se_a)]) == 1
-    se_c in st.forward_references[id(se_a)]
+    assert se_c in st.forward_references[id(se_a)]
     assert len(st.forward_references[id(se_b)]) == 0
     assert len(st.forward_references[id(se_c)]) == 0
     assert len(st.backward_references[id(se_a)]) == 0
     assert len(st.backward_references[id(se_b)]) == 0
     assert len(st.backward_references[id(se_c)]) == 1
-    se_a in st.backward_references[id(se_c)]
+    assert se_a in st.backward_references[id(se_c)]
 
     assert len(st.forward_id_references[id(se_a)]) == 1
-    se_c in st.forward_id_references[id(se_a)]
+    assert se_c in st.forward_id_references[id(se_a)]
     assert len(st.forward_id_references[id(se_b)]) == 0
     assert len(st.forward_id_references[id(se_c)]) == 0
     assert len(st.backward_id_references[id(se_a)]) == 0
     assert len(st.backward_id_references[id(se_b)]) == 0
     assert len(st.backward_id_references[id(se_c)]) == 1
-    se_a in st.backward_id_references[id(se_c)]
+    assert se_a in st.backward_id_references[id(se_c)]
 
     assert len(st.forward_id_referenced_by[id(se_a)]) == 1
-    se_c in st.forward_id_referenced_by[id(se_a)]
+    assert se_c in st.forward_id_referenced_by[id(se_a)]
     assert len(st.forward_id_referenced_by[id(se_b)]) == 0
     assert len(st.forward_id_referenced_by[id(se_c)]) == 0
     assert len(st.backward_id_referenced_by[id(se_a)]) == 0
     assert len(st.backward_id_referenced_by[id(se_b)]) == 0
     assert len(st.backward_id_referenced_by[id(se_c)]) == 1
-    se_a in st.backward_id_referenced_by[id(se_c)]
+    assert se_a in st.backward_id_referenced_by[id(se_c)]
 
     st.set_id_of_node(se_a, 101)
 
@@ -227,30 +227,30 @@ def test_merge_into_trivial(simple_adapter):
     # c is now referenced by b
     assert id(se_a) not in st.forward_references
     assert len(st.forward_references[id(se_b)]) == 1
-    se_c in st.forward_references[id(se_b)]
+    assert se_c in st.forward_references[id(se_b)]
     assert len(st.forward_references[id(se_c)]) == 0
     assert id(se_a) not in st.backward_references
     assert len(st.backward_references[id(se_b)]) == 0
     assert len(st.backward_references[id(se_c)]) == 1
-    se_b in st.backward_references[id(se_c)]
+    assert se_b in st.backward_references[id(se_c)]
 
     assert id(se_a) not in st.forward_id_references
     assert len(st.forward_id_references[id(se_b)]) == 1
-    se_c in st.forward_id_references[id(se_b)]
+    assert se_c in st.forward_id_references[id(se_b)]
     assert len(st.forward_id_references[id(se_c)]) == 0
     assert id(se_a) not in st.backward_id_references
     assert len(st.backward_id_references[id(se_b)]) == 0
     assert len(st.backward_id_references[id(se_c)]) == 1
-    se_b in st.backward_id_references[id(se_c)]
+    assert se_b in st.backward_id_references[id(se_c)]
 
     assert id(se_a) not in st.forward_id_referenced_by
     assert len(st.forward_id_referenced_by[id(se_b)]) == 1
-    se_c in st.forward_id_referenced_by[id(se_b)]
+    assert se_c in st.forward_id_referenced_by[id(se_b)]
     assert len(st.forward_id_referenced_by[id(se_c)]) == 0
     assert id(se_a) not in st.backward_id_referenced_by
     assert len(st.backward_id_referenced_by[id(se_b)]) == 0
     assert len(st.backward_id_referenced_by[id(se_c)]) == 1
-    se_b in st.backward_id_referenced_by[id(se_c)]
+    assert se_b in st.backward_id_referenced_by[id(se_c)]
 
 
 def test_merge_into_simple(simple_adapter):