Issue #22995: Default implementation of __reduce__ and __reduce_ex__ now

rejects builtin types with not defined __new__.
Added tests for non-pickleable types.

Lib/test/test_generators.py

@@ -1,4 +1,6 @@
+import copy
 import gc
+import pickle
 import sys
 import unittest
 import weakref
@@ -70,6 +72,24 @@ class FinalizationTest(unittest.TestCase):
             self.assertEqual(cm.exception.value, 2)
 
 
+class GeneratorTest(unittest.TestCase):
+
+    def test_copy(self):
+        def f():
+            yield 1
+        g = f()
+        with self.assertRaises(TypeError):
+            copy.copy(g)
+
+    def test_pickle(self):
+        def f():
+            yield 1
+        g = f()
+        for proto in range(pickle.HIGHEST_PROTOCOL + 1):
+            with self.assertRaises((TypeError, pickle.PicklingError)):
+                pickle.dumps(g, proto)
+
+
 class ExceptionTest(unittest.TestCase):
     # Tests for the issue #23353: check that the currently handled exception
     # is correctly saved/restored in PyEval_EvalFrameEx().