Issue #26015: Added new tests for pickling iterators of mutable sequences.

1 files changed, 38 insertions, 11 deletions

diff --git a/Lib/test/test_deque.py b/Lib/test/test_deque.py
index 634d71f..29b44f6 100644
--- a/Lib/test/test_deque.py
+++ b/Lib/test/test_deque.py
@@ -640,18 +640,45 @@ class TestBasic(unittest.TestCase):
                 self.assertEqual(e.maxlen, d.maxlen)
 
     def test_iterator_pickle(self):
-        data = deque(range(200))
+        orig = deque(range(200))
+        data = [i*1.01 for i in orig]
         for proto in range(pickle.HIGHEST_PROTOCOL + 1):
-            it = itorg = iter(data)
-            d = pickle.dumps(it, proto)
-            it = pickle.loads(d)
-            self.assertEqual(type(itorg), type(it))
-            self.assertEqual(list(it), list(data))
-
-            it = pickle.loads(d)
-            next(it)
-            d = pickle.dumps(it, proto)
-            self.assertEqual(list(it), list(data)[1:])
+            # initial iterator
+            itorg = iter(orig)
+            dump = pickle.dumps((itorg, orig), proto)
+            it, d = pickle.loads(dump)
+            for i, x in enumerate(data):
+                d[i] = x
+            self.assertEqual(type(it), type(itorg))
+            self.assertEqual(list(it), data)
+
+            # running iterator
+            next(itorg)
+            dump = pickle.dumps((itorg, orig), proto)
+            it, d = pickle.loads(dump)
+            for i, x in enumerate(data):
+                d[i] = x
+            self.assertEqual(type(it), type(itorg))
+            self.assertEqual(list(it), data[1:])
+
+            # empty iterator
+            for i in range(1, len(data)):
+                next(itorg)
+            dump = pickle.dumps((itorg, orig), proto)
+            it, d = pickle.loads(dump)
+            for i, x in enumerate(data):
+                d[i] = x
+            self.assertEqual(type(it), type(itorg))
+            self.assertEqual(list(it), [])
+
+            # exhausted iterator
+            self.assertRaises(StopIteration, next, itorg)
+            dump = pickle.dumps((itorg, orig), proto)
+            it, d = pickle.loads(dump)
+            for i, x in enumerate(data):
+                d[i] = x
+            self.assertEqual(type(it), type(itorg))
+            self.assertEqual(list(it), [])
 
     def test_deepcopy(self):
         mut = [10]