diff --git a/test/test_structures.py b/test/test_structures.py
index de959cdca..19423adda 100644
--- a/test/test_structures.py
+++ b/test/test_structures.py
@@ -585,8 +585,10 @@ class TestTimeoutQueue(SupyTestCase):
         self.assertEqual(len(q), 2)
         q.enqueue(3)
         self.assertEqual(len(q), 3)
+        self.assertEqual(sum(q), 6)
         time.sleep(1)
         self.assertEqual(len(q), 0)
+        self.assertEqual(sum(q), 0)
         
 
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