1 files changed, 51 insertions, 0 deletions
diff --git a/Lib/test/test_iter.py b/Lib/test/test_iter.py
index abc408f..a91670b 100644
--- a/Lib/test/test_iter.py
+++ b/Lib/test/test_iter.py
@@ -3,6 +3,7 @@
 import sys
 import unittest
 from test.support import run_unittest, TESTFN, unlink, cpython_only
+from test.support import check_free_after_iterating
 import pickle
 import collections.abc
 
@@ -153,6 +154,53 @@ class TestCase(unittest.TestCase):
     def test_seq_class_iter(self):
         self.check_iterator(iter(SequenceClass(10)), list(range(10)))
 
+    def test_mutating_seq_class_iter_pickle(self):
+        orig = SequenceClass(5)
+        for proto in range(pickle.HIGHEST_PROTOCOL + 1):
+            # initial iterator
+            itorig = iter(orig)
+            d = pickle.dumps((itorig, orig), proto)
+            it, seq = pickle.loads(d)
+            seq.n = 7
+            self.assertIs(type(it), type(itorig))
+            self.assertEqual(list(it), list(range(7)))
+
+            # running iterator
+            next(itorig)
+            d = pickle.dumps((itorig, orig), proto)
+            it, seq = pickle.loads(d)
+            seq.n = 7
+            self.assertIs(type(it), type(itorig))
+            self.assertEqual(list(it), list(range(1, 7)))
+
+            # empty iterator
+            for i in range(1, 5):
+                next(itorig)
+            d = pickle.dumps((itorig, orig), proto)
+            it, seq = pickle.loads(d)
+            seq.n = 7
+            self.assertIs(type(it), type(itorig))
+            self.assertEqual(list(it), list(range(5, 7)))
+
+            # exhausted iterator
+            self.assertRaises(StopIteration, next, itorig)
+            d = pickle.dumps((itorig, orig), proto)
+            it, seq = pickle.loads(d)
+            seq.n = 7
+            self.assertTrue(isinstance(it, collections.abc.Iterator))
+            self.assertEqual(list(it), [])
+
+    def test_mutating_seq_class_exhausted_iter(self):
+        a = SequenceClass(5)
+        exhit = iter(a)
+        empit = iter(a)
+        for x in exhit:  # exhaust the iterator
+            next(empit)  # not exhausted
+        a.n = 7
+        self.assertEqual(list(exhit), [])
+        self.assertEqual(list(empit), [5, 6])
+        self.assertEqual(list(a), [0, 1, 2, 3, 4, 5, 6])
+
     # Test a new_style class with __iter__ but no next() method
     def test_new_style_iter_class(self):
         class IterClass(object):
@@ -944,6 +992,9 @@ class TestCase(unittest.TestCase):
         self.assertEqual(next(it), 0)
         self.assertEqual(next(it), 1)
 
+    def test_free_after_iterating(self):
+        check_free_after_iterating(self, iter, SequenceClass, (0,))
+
 
 def test_main():
     run_unittest(TestCase)