Issue #22777: Test pickling with all protocols.
diff --git a/Lib/test/test_cfgparser.py b/Lib/test/test_cfgparser.py
index df65f6e..906e9cf 100644
--- a/Lib/test/test_cfgparser.py
+++ b/Lib/test/test_cfgparser.py
@@ -614,88 +614,96 @@
     def test_error(self):
         import pickle
         e1 = ConfigParser.Error('value')
-        pickled = pickle.dumps(e1)
-        e2 = pickle.loads(pickled)
-        self.assertEqual(e1.message, e2.message)
-        self.assertEqual(repr(e1), repr(e2))
+        for proto in range(pickle.HIGHEST_PROTOCOL + 1):
+            pickled = pickle.dumps(e1, proto)
+            e2 = pickle.loads(pickled)
+            self.assertEqual(e1.message, e2.message)
+            self.assertEqual(repr(e1), repr(e2))
 
     def test_nosectionerror(self):
         import pickle
         e1 = ConfigParser.NoSectionError('section')
-        pickled = pickle.dumps(e1)
-        e2 = pickle.loads(pickled)
-        self.assertEqual(e1.message, e2.message)
-        self.assertEqual(e1.args, e2.args)
-        self.assertEqual(e1.section, e2.section)
-        self.assertEqual(repr(e1), repr(e2))
+        for proto in range(pickle.HIGHEST_PROTOCOL + 1):
+            pickled = pickle.dumps(e1, proto)
+            e2 = pickle.loads(pickled)
+            self.assertEqual(e1.message, e2.message)
+            self.assertEqual(e1.args, e2.args)
+            self.assertEqual(e1.section, e2.section)
+            self.assertEqual(repr(e1), repr(e2))
 
     def test_nooptionerror(self):
         import pickle
         e1 = ConfigParser.NoOptionError('option', 'section')
-        pickled = pickle.dumps(e1)
-        e2 = pickle.loads(pickled)
-        self.assertEqual(e1.message, e2.message)
-        self.assertEqual(e1.args, e2.args)
-        self.assertEqual(e1.section, e2.section)
-        self.assertEqual(e1.option, e2.option)
-        self.assertEqual(repr(e1), repr(e2))
+        for proto in range(pickle.HIGHEST_PROTOCOL + 1):
+            pickled = pickle.dumps(e1, proto)
+            e2 = pickle.loads(pickled)
+            self.assertEqual(e1.message, e2.message)
+            self.assertEqual(e1.args, e2.args)
+            self.assertEqual(e1.section, e2.section)
+            self.assertEqual(e1.option, e2.option)
+            self.assertEqual(repr(e1), repr(e2))
 
     def test_duplicatesectionerror(self):
         import pickle
         e1 = ConfigParser.DuplicateSectionError('section')
-        pickled = pickle.dumps(e1)
-        e2 = pickle.loads(pickled)
-        self.assertEqual(e1.message, e2.message)
-        self.assertEqual(e1.args, e2.args)
-        self.assertEqual(e1.section, e2.section)
-        self.assertEqual(repr(e1), repr(e2))
+        for proto in range(pickle.HIGHEST_PROTOCOL + 1):
+            pickled = pickle.dumps(e1, proto)
+            e2 = pickle.loads(pickled)
+            self.assertEqual(e1.message, e2.message)
+            self.assertEqual(e1.args, e2.args)
+            self.assertEqual(e1.section, e2.section)
+            self.assertEqual(repr(e1), repr(e2))
 
     def test_interpolationerror(self):
         import pickle
         e1 = ConfigParser.InterpolationError('option', 'section', 'msg')
-        pickled = pickle.dumps(e1)
-        e2 = pickle.loads(pickled)
-        self.assertEqual(e1.message, e2.message)
-        self.assertEqual(e1.args, e2.args)
-        self.assertEqual(e1.section, e2.section)
-        self.assertEqual(e1.option, e2.option)
-        self.assertEqual(repr(e1), repr(e2))
+        for proto in range(pickle.HIGHEST_PROTOCOL + 1):
+            pickled = pickle.dumps(e1, proto)
+            e2 = pickle.loads(pickled)
+            self.assertEqual(e1.message, e2.message)
+            self.assertEqual(e1.args, e2.args)
+            self.assertEqual(e1.section, e2.section)
+            self.assertEqual(e1.option, e2.option)
+            self.assertEqual(repr(e1), repr(e2))
 
     def test_interpolationmissingoptionerror(self):
         import pickle
         e1 = ConfigParser.InterpolationMissingOptionError('option', 'section',
             'rawval', 'reference')
-        pickled = pickle.dumps(e1)
-        e2 = pickle.loads(pickled)
-        self.assertEqual(e1.message, e2.message)
-        self.assertEqual(e1.args, e2.args)
-        self.assertEqual(e1.section, e2.section)
-        self.assertEqual(e1.option, e2.option)
-        self.assertEqual(e1.reference, e2.reference)
-        self.assertEqual(repr(e1), repr(e2))
+        for proto in range(pickle.HIGHEST_PROTOCOL + 1):
+            pickled = pickle.dumps(e1, proto)
+            e2 = pickle.loads(pickled)
+            self.assertEqual(e1.message, e2.message)
+            self.assertEqual(e1.args, e2.args)
+            self.assertEqual(e1.section, e2.section)
+            self.assertEqual(e1.option, e2.option)
+            self.assertEqual(e1.reference, e2.reference)
+            self.assertEqual(repr(e1), repr(e2))
 
     def test_interpolationsyntaxerror(self):
         import pickle
         e1 = ConfigParser.InterpolationSyntaxError('option', 'section', 'msg')
-        pickled = pickle.dumps(e1)
-        e2 = pickle.loads(pickled)
-        self.assertEqual(e1.message, e2.message)
-        self.assertEqual(e1.args, e2.args)
-        self.assertEqual(e1.section, e2.section)
-        self.assertEqual(e1.option, e2.option)
-        self.assertEqual(repr(e1), repr(e2))
+        for proto in range(pickle.HIGHEST_PROTOCOL + 1):
+            pickled = pickle.dumps(e1, proto)
+            e2 = pickle.loads(pickled)
+            self.assertEqual(e1.message, e2.message)
+            self.assertEqual(e1.args, e2.args)
+            self.assertEqual(e1.section, e2.section)
+            self.assertEqual(e1.option, e2.option)
+            self.assertEqual(repr(e1), repr(e2))
 
     def test_interpolationdeptherror(self):
         import pickle
         e1 = ConfigParser.InterpolationDepthError('option', 'section',
             'rawval')
-        pickled = pickle.dumps(e1)
-        e2 = pickle.loads(pickled)
-        self.assertEqual(e1.message, e2.message)
-        self.assertEqual(e1.args, e2.args)
-        self.assertEqual(e1.section, e2.section)
-        self.assertEqual(e1.option, e2.option)
-        self.assertEqual(repr(e1), repr(e2))
+        for proto in range(pickle.HIGHEST_PROTOCOL + 1):
+            pickled = pickle.dumps(e1, proto)
+            e2 = pickle.loads(pickled)
+            self.assertEqual(e1.message, e2.message)
+            self.assertEqual(e1.args, e2.args)
+            self.assertEqual(e1.section, e2.section)
+            self.assertEqual(e1.option, e2.option)
+            self.assertEqual(repr(e1), repr(e2))
 
     def test_parsingerror(self):
         import pickle
@@ -703,25 +711,27 @@
         e1.append(1, 'line1')
         e1.append(2, 'line2')
         e1.append(3, 'line3')
-        pickled = pickle.dumps(e1)
-        e2 = pickle.loads(pickled)
-        self.assertEqual(e1.message, e2.message)
-        self.assertEqual(e1.args, e2.args)
-        self.assertEqual(e1.filename, e2.filename)
-        self.assertEqual(e1.errors, e2.errors)
-        self.assertEqual(repr(e1), repr(e2))
+        for proto in range(pickle.HIGHEST_PROTOCOL + 1):
+            pickled = pickle.dumps(e1, proto)
+            e2 = pickle.loads(pickled)
+            self.assertEqual(e1.message, e2.message)
+            self.assertEqual(e1.args, e2.args)
+            self.assertEqual(e1.filename, e2.filename)
+            self.assertEqual(e1.errors, e2.errors)
+            self.assertEqual(repr(e1), repr(e2))
 
     def test_missingsectionheadererror(self):
         import pickle
         e1 = ConfigParser.MissingSectionHeaderError('filename', 123, 'line')
-        pickled = pickle.dumps(e1)
-        e2 = pickle.loads(pickled)
-        self.assertEqual(e1.message, e2.message)
-        self.assertEqual(e1.args, e2.args)
-        self.assertEqual(e1.line, e2.line)
-        self.assertEqual(e1.filename, e2.filename)
-        self.assertEqual(e1.lineno, e2.lineno)
-        self.assertEqual(repr(e1), repr(e2))
+        for proto in range(pickle.HIGHEST_PROTOCOL + 1):
+            pickled = pickle.dumps(e1, proto)
+            e2 = pickle.loads(pickled)
+            self.assertEqual(e1.message, e2.message)
+            self.assertEqual(e1.args, e2.args)
+            self.assertEqual(e1.line, e2.line)
+            self.assertEqual(e1.filename, e2.filename)
+            self.assertEqual(e1.lineno, e2.lineno)
+            self.assertEqual(repr(e1), repr(e2))
 
 
 def test_main():