Issue #14288: Serialization support for builtin iterators.

1 files changed, 54 insertions, 0 deletions

diff --git a/Lib/test/test_dict.py b/Lib/test/test_dict.py
index 387dd32..b43e20d 100644
--- a/Lib/test/test_dict.py
+++ b/Lib/test/test_dict.py
@@ -2,7 +2,9 @@ import unittest
 from test import support
 
 import collections, random, string
+import collections.abc
 import gc, weakref
+import pickle
 
 
 class DictTest(unittest.TestCase):
@@ -803,6 +805,58 @@ class DictTest(unittest.TestCase):
             pass
         self._tracked(MyDict())
 
+    def test_iterator_pickling(self):
+        data = {1:"a", 2:"b", 3:"c"}
+        it = iter(data)
+        d = pickle.dumps(it)
+        it = pickle.loads(d)
+        self.assertEqual(sorted(it), sorted(data))
+
+        it = pickle.loads(d)
+        try:
+            drop = next(it)
+        except StopIteration:
+            return
+        d = pickle.dumps(it)
+        it = pickle.loads(d)
+        del data[drop]
+        self.assertEqual(sorted(it), sorted(data))
+
+    def test_itemiterator_pickling(self):
+        data = {1:"a", 2:"b", 3:"c"}
+        # dictviews aren't picklable, only their iterators
+        itorg = iter(data.items())
+        d = pickle.dumps(itorg)
+        it = pickle.loads(d)
+        # note that the type of type of the unpickled iterator
+        # is not necessarily the same as the original.  It is
+        # merely an object supporting the iterator protocol, yielding
+        # the same objects as the original one.
+        # self.assertEqual(type(itorg), type(it))
+        self.assertTrue(isinstance(it, collections.abc.Iterator))
+        self.assertEqual(dict(it), data)
+
+        it = pickle.loads(d)
+        drop = next(it)
+        d = pickle.dumps(it)
+        it = pickle.loads(d)
+        del data[drop[0]]
+        self.assertEqual(dict(it), data)
+
+    def test_valuesiterator_pickling(self):
+        data = {1:"a", 2:"b", 3:"c"}
+        # data.values() isn't picklable, only its iterator
+        it = iter(data.values())
+        d = pickle.dumps(it)
+        it = pickle.loads(d)
+        self.assertEqual(sorted(list(it)), sorted(list(data.values())))
+
+        it = pickle.loads(d)
+        drop = next(it)
+        d = pickle.dumps(it)
+        it = pickle.loads(d)
+        values = list(it) + [drop]
+        self.assertEqual(sorted(values), sorted(list(data.values())))
 
 from test import mapping_tests