diff --git a/Lib/test/test_datetime.py b/Lib/test/test_datetime.py
index 0b9597a..995b6a0 100644
--- a/Lib/test/test_datetime.py
+++ b/Lib/test/test_datetime.py
@@ -880,6 +880,44 @@
             self.assertRaises(TypeError, lambda: badarg > t1)
             self.assertRaises(TypeError, lambda: badarg >= t1)
 
+    def test_mixed_compare(self):
+        our = self.theclass(2000, 4, 5)
+        self.assertRaises(TypeError, cmp, our, 1)
+        self.assertRaises(TypeError, cmp, 1, our)
+
+        class AnotherDateTimeClass(object):
+            def __cmp__(self, other):
+                # Return "equal" so calling this can't be confused with
+                # compare-by-address (which never says "equal" for distinct
+                # objects).
+                return 0
+
+        # This still errors, because date and datetime comparison raise
+        # TypeError instead of NotImplemented when they don't know what to
+        # do, in order to stop comparison from falling back to the default
+        # compare-by-address.
+        their = AnotherDateTimeClass()
+        self.assertRaises(TypeError, cmp, our, their)
+        # Oops:  The next stab raises TypeError in the C implementation,
+        # but not in the Python implementation of datetime.  The difference
+        # is due to that the Python implementation defines __cmp__ but
+        # the C implementation defines tp_richcompare.  This is more pain
+        # to fix than it's worth, so commenting out the test.
+        # self.assertEqual(cmp(their, our), 0)
+
+        # But date and datetime comparison return NotImplemented instead if the
+        # other object has a timetuple attr.  This gives the other object a
+        # chance to do the comparison.
+        class Comparable(AnotherDateTimeClass):
+            def timetuple(self):
+                return ()
+
+        their = Comparable()
+        self.assertEqual(cmp(our, their), 0)
+        self.assertEqual(cmp(their, our), 0)
+        self.failUnless(our == their)
+        self.failUnless(their == our)
+
     def test_bool(self):
         # All dates are considered true.
         self.failUnless(self.theclass.min)