1 files changed, 13 insertions, 0 deletions
diff --git a/Lib/test/test_iter.py b/Lib/test/test_iter.py
index 66f40c1..5584587 100644
--- a/Lib/test/test_iter.py
+++ b/Lib/test/test_iter.py
@@ -385,4 +385,17 @@ class TestCase(unittest.TestCase):
             except OSError:
                 pass
 
+    # Test reduces()'s use of iterators.
+    def test_builtin_reduce(self):
+        from operator import add
+        self.assertEqual(reduce(add, SequenceClass(5)), 10)
+        self.assertEqual(reduce(add, SequenceClass(5), 42), 52)
+        self.assertRaises(TypeError, reduce, add, SequenceClass(0))
+        self.assertEqual(reduce(add, SequenceClass(0), 42), 42)
+        self.assertEqual(reduce(add, SequenceClass(1)), 0)
+        self.assertEqual(reduce(add, SequenceClass(1), 42), 42)
+
+        d = {"one": 1, "two": 2, "three": 3}
+        self.assertEqual(reduce(add, d), "".join(d.keys()))
+
 run_unittest(TestCase)