Issue #14288: Serialization support for builtin iterators.

Lib/test/test_bytes.py

@@ -518,6 +518,24 @@ class BaseBytesTest(unittest.TestCase):
                 q = pickle.loads(ps)
                 self.assertEqual(b, q)
 
+    def test_iterator_pickling(self):
+        for b in b"", b"a", b"abc", b"\xffab\x80", b"\0\0\377\0\0":
+            it = itorg = iter(self.type2test(b))
+            data = list(self.type2test(b))
+            d = pickle.dumps(it)
+            it = pickle.loads(d)
+            self.assertEqual(type(itorg), type(it))
+            self.assertEqual(list(it), data)
+
+            it = pickle.loads(d)
+            try:
+                next(it)
+            except StopIteration:
+                continue
+            d = pickle.dumps(it)
+            it = pickle.loads(d)
+            self.assertEqual(list(it), data[1:])
+
     def test_strip(self):
         b = self.type2test(b'mississippi')
         self.assertEqual(b.strip(b'i'), b'mississipp')