diff --git a/Lib/test/test_deque.py b/Lib/test/test_deque.py
index 7af0803..27c89c4 100644
--- a/Lib/test/test_deque.py
+++ b/Lib/test/test_deque.py
@@ -1,7 +1,8 @@
 from collections import deque
 import unittest
 from test import support, seq_tests
-from weakref import proxy
+import gc
+import weakref
 import copy
 import pickle
 from io import StringIO
@@ -420,6 +421,22 @@
             d.append(1)
             gc.collect()
 
+    def test_container_iterator(self):
+        # Bug #3680: tp_traverse was not implemented for deque iterator objects
+        class C(object):
+            pass
+        for i in range(2):
+            obj = C()
+            ref = weakref.ref(obj)
+            if i == 0:
+                container = deque([obj, 1])
+            else:
+                container = reversed(deque([obj, 1]))
+            obj.x = iter(container)
+            del obj, container
+            gc.collect()
+            self.assert_(ref() is None, "Cycle was not collected")
+
 class TestVariousIteratorArgs(unittest.TestCase):
 
     def test_constructor(self):
@@ -530,7 +547,7 @@
 
     def test_weakref(self):
         d = deque('gallahad')
-        p = proxy(d)
+        p = weakref.proxy(d)
         self.assertEqual(str(p), str(d))
         d = None
         self.assertRaises(ReferenceError, str, p)
diff --git a/Lib/test/test_dict.py b/Lib/test/test_dict.py
index 403d5eb..2e74b68 100644
--- a/Lib/test/test_dict.py
+++ b/Lib/test/test_dict.py
@@ -2,6 +2,7 @@
 from test import support
 
 import sys, collections, random, string
+import gc, weakref
 
 
 class DictTest(unittest.TestCase):
@@ -648,6 +649,21 @@
             pass
         d = {}
 
+    def test_container_iterator(self):
+        # Bug #3680: tp_traverse was not implemented for dictiter and
+        # dictview objects.
+        class C(object):
+            pass
+        views = (dict.items, dict.values, dict.keys)
+        for v in views:
+            obj = C()
+            ref = weakref.ref(obj)
+            container = {obj: 1}
+            obj.v = v(container)
+            obj.x = iter(obj.v)
+            del obj, container
+            gc.collect()
+            self.assert_(ref() is None, "Cycle was not collected")
 
 
 from test import mapping_tests
diff --git a/Lib/test/test_set.py b/Lib/test/test_set.py
index da3ed0f..5a8819f 100644
--- a/Lib/test/test_set.py
+++ b/Lib/test/test_set.py
@@ -1,6 +1,7 @@
 import unittest
 from test import support
-from weakref import proxy
+import gc
+import weakref
 import operator
 import copy
 import pickle
@@ -323,6 +324,18 @@
         self.assertEqual(sum(elem.hash_count for elem in d), n)
         self.assertEqual(d3, dict.fromkeys(d, 123))
 
+    def test_container_iterator(self):
+        # Bug #3680: tp_traverse was not implemented for set iterator object
+        class C(object):
+            pass
+        obj = C()
+        ref = weakref.ref(obj)
+        container = set([obj, 1])
+        obj.x = iter(container)
+        del obj, container
+        gc.collect()
+        self.assert_(ref() is None, "Cycle was not collected")
+
 class TestSet(TestJointOps):
     thetype = set
     basetype = set
@@ -546,7 +559,7 @@
 
     def test_weakref(self):
         s = self.thetype('gallahad')
-        p = proxy(s)
+        p = weakref.proxy(s)
         self.assertEqual(str(p), str(s))
         s = None
         self.assertRaises(ReferenceError, str, p)