diff --git a/Doc/howto/sockets.rst b/Doc/howto/sockets.rst
index 3927544b700..1ecf3440f5a 100644
--- a/Doc/howto/sockets.rst
+++ b/Doc/howto/sockets.rst
@@ -43,10 +43,10 @@ web server it's talking to uses both "server" sockets and "client" sockets.
 History
 -------
 
-Of the various forms of IPC (*Inter Process Communication*), sockets are by far
-the most popular.  On any given platform, there are likely to be other forms of
-IPC that are faster, but for cross-platform communication, sockets are about the
-only game in town.
+Of the various forms of :abbr:`IPC (Inter Process Communication)`,
+sockets are by far the most popular.  On any given platform, there are
+likely to be other forms of IPC that are faster, but for
+cross-platform communication, sockets are about the only game in town.
 
 They were invented in Berkeley as part of the BSD flavor of Unix. They spread
 like wildfire with the Internet. With good reason --- the combination of sockets
@@ -66,13 +66,14 @@ your browser did something like the following::
    # - the normal http port
    s.connect(("www.mcmillan-inc.com", 80))
 
-When the ``connect`` completes, the socket ``s`` can now be used to send in a
-request for the text of this page. The same socket will read the reply, and then
-be destroyed. That's right - destroyed. Client sockets are normally only used
-for one exchange (or a small set of sequential exchanges).
+When the ``connect`` completes, the socket ``s`` can be used to send
+in a request for the text of the page. The same socket will read the
+reply, and then be destroyed. That's right, destroyed. Client sockets
+are normally only used for one exchange (or a small set of sequential
+exchanges).
 
 What happens in the web server is a bit more complex. First, the web server
-creates a "server socket". ::
+creates a "server socket"::
 
    #create an INET, STREAMing socket
    serversocket = socket.socket(
@@ -96,7 +97,7 @@ Finally, the argument to ``listen`` tells the socket library that we want it to
 queue up as many as 5 connect requests (the normal max) before refusing outside
 connections. If the rest of the code is written properly, that should be plenty.
 
-OK, now we have a "server" socket, listening on port 80. Now we enter the
+Now that we have a "server" socket, listening on port 80, we can enter the
 mainloop of the web server::
 
    while True:
@@ -145,7 +146,7 @@ perhaps a signon. But that's a design decision - it's not a rule of sockets.
 
 Now there are two sets of verbs to use for communication. You can use ``send``
 and ``recv``, or you can transform your client socket into a file-like beast and
-use ``read`` and ``write``. The latter is the way Java presents their sockets.
+use ``read`` and ``write``. The latter is the way Java presents its sockets.
 I'm not going to talk about it here, except to warn you that you need to use
 ``flush`` on sockets. These are buffered "files", and a common mistake is to
 ``write`` something, and then ``read`` for a reply. Without a ``flush`` in
@@ -166,11 +167,11 @@ this connection. Ever.  You may be able to send data successfully; I'll talk
 about that some on the next page.
 
 A protocol like HTTP uses a socket for only one transfer. The client sends a
-request, the reads a reply.  That's it. The socket is discarded. This means that
+request, then reads a reply.  That's it. The socket is discarded. This means that
 a client can detect the end of the reply by receiving 0 bytes.
 
 But if you plan to reuse your socket for further transfers, you need to realize
-that *there is no "EOT" (End of Transfer) on a socket.* I repeat: if a socket
+that *there is no* :abbr:`EOT (End of Transfer)` *on a socket.* I repeat: if a socket
 ``send`` or ``recv`` returns after handling 0 bytes, the connection has been
 broken.  If the connection has *not* been broken, you may wait on a ``recv``
 forever, because the socket will *not* tell you that there's nothing more to
@@ -336,7 +337,7 @@ Use ``select``.
 
 In C, coding ``select`` is fairly complex. In Python, it's a piece of cake, but
 it's close enough to the C version that if you understand ``select`` in Python,
-you'll have little trouble with it in C. ::
+you'll have little trouble with it in C::
 
    ready_to_read, ready_to_write, in_error = \
                   select.select(
@@ -353,9 +354,9 @@ call is blocking, but you can give it a timeout. This is generally a sensible
 thing to do - give it a nice long timeout (say a minute) unless you have good
 reason to do otherwise.
 
-In return, you will get three lists. They have the sockets that are actually
+In return, you will get three lists. They contain the sockets that are actually
 readable, writable and in error. Each of these lists is a subset (possibly
-empty) of the corresponding list you passed in. And if you put a socket in more
+empty) of the corresponding list you passed in. If you put a socket in more
 than one input list, it will only be (at most) in one output list.
 
 If a socket is in the output readable list, you can be
diff --git a/Doc/library/pprint.rst b/Doc/library/pprint.rst
index 9ab12eea1d8..fc54208d151 100644
--- a/Doc/library/pprint.rst
+++ b/Doc/library/pprint.rst
@@ -189,37 +189,105 @@ are converted to strings.  The default implementation uses the internals of the
 
 .. _pprint-example:
 
-pprint Example
---------------
+Example
+-------
 
-This example demonstrates several uses of the :func:`pprint` function and its
-parameters.
+To demonstrate several uses of the :func:`pprint` function and its parameters,
+let's fetch information about a package from PyPI::
 
+   >>> import json
    >>> import pprint
-   >>> tup = ('spam', ('eggs', ('lumberjack', ('knights', ('ni', ('dead',
-   ... ('parrot', ('fresh fruit',))))))))
-   >>> stuff = ['a' * 10, tup, ['a' * 30, 'b' * 30], ['c' * 20, 'd' * 20]]
-   >>> pprint.pprint(stuff)
-   ['aaaaaaaaaa',
-    ('spam',
-     ('eggs',
-      ('lumberjack',
-       ('knights', ('ni', ('dead', ('parrot', ('fresh fruit',)))))))),
-    ['aaaaaaaaaaaaaaaaaaaaaaaaaaaaaa', 'bbbbbbbbbbbbbbbbbbbbbbbbbbbbbb'],
-    ['cccccccccccccccccccc', 'dddddddddddddddddddd']]
-   >>> pprint.pprint(stuff, depth=3)
-   ['aaaaaaaaaa',
-    ('spam', ('eggs', (...))),
-    ['aaaaaaaaaaaaaaaaaaaaaaaaaaaaaa', 'bbbbbbbbbbbbbbbbbbbbbbbbbbbbbb'],
-    ['cccccccccccccccccccc', 'dddddddddddddddddddd']]
-   >>> pprint.pprint(stuff, width=60)
-   ['aaaaaaaaaa',
-    ('spam',
-     ('eggs',
-      ('lumberjack',
-       ('knights',
-        ('ni', ('dead', ('parrot', ('fresh fruit',)))))))),
-    ['aaaaaaaaaaaaaaaaaaaaaaaaaaaaaa',
-     'bbbbbbbbbbbbbbbbbbbbbbbbbbbbbb'],
-    ['cccccccccccccccccccc', 'dddddddddddddddddddd']]
+   >>> from urllib.request import urlopen
+   >>> with urlopen('http://pypi.python.org/pypi/configparser/json') as url:
+   ...     http_info = url.info()
+   ...     raw_data = url.read().decode(http_info.get_content_charset())
+   >>> package_data = json.loads(raw_data)
+   >>> result = {'headers': http_info.items(), 'body': package_data}
 
+In its basic form, :func:`pprint` shows the whole object::
+
+   >>> pprint.pprint(result)
+   {'body': {'info': {'_pypi_hidden': False,
+                      '_pypi_ordering': 12,
+                      'classifiers': ['Development Status :: 4 - Beta',
+                                      'Intended Audience :: Developers',
+                                      'License :: OSI Approved :: MIT License',
+                                      'Natural Language :: English',
+                                      'Operating System :: OS Independent',
+                                      'Programming Language :: Python',
+                                      'Programming Language :: Python :: 2',
+                                      'Programming Language :: Python :: 2.6',
+                                      'Programming Language :: Python :: 2.7',
+                                      'Topic :: Software Development :: Libraries',
+                                      'Topic :: Software Development :: Libraries :: Python Modules'],
+                      'download_url': 'UNKNOWN',
+                      'home_page': 'http://docs.python.org/py3k/library/configparser.html',
+                      'keywords': 'configparser ini parsing conf cfg configuration file',
+                      'license': 'MIT',
+                      'name': 'configparser',
+                      'package_url': 'http://pypi.python.org/pypi/configparser',
+                      'platform': 'any',
+                      'release_url': 'http://pypi.python.org/pypi/configparser/3.2.0r3',
+                      'requires_python': None,
+                      'stable_version': None,
+                      'summary': 'This library brings the updated configparser from Python 3.2+ to Python 2.6-2.7.',
+                      'version': '3.2.0r3'},
+           'urls': [{'comment_text': '',
+                     'downloads': 47,
+                     'filename': 'configparser-3.2.0r3.tar.gz',
+                     'has_sig': False,
+                     'md5_digest': '8500fd87c61ac0de328fc996fce69b96',
+                     'packagetype': 'sdist',
+                     'python_version': 'source',
+                     'size': 32281,
+                     'upload_time': '2011-05-10T16:28:50',
+                     'url': 'http://pypi.python.org/packages/source/c/configparser/configparser-3.2.0r3.tar.gz'}]},
+   'headers': [('Date', 'Sat, 14 May 2011 12:48:52 GMT'),
+               ('Server', 'Apache/2.2.16 (Debian)'),
+               ('Content-Disposition', 'inline'),
+               ('Connection', 'close'),
+               ('Transfer-Encoding', 'chunked'),
+               ('Content-Type', 'application/json; charset="UTF-8"')]}
+
+The result can be limited to a certain *depth* (ellipsis is used for deeper
+contents)::
+
+   >>> pprint.pprint(result, depth=3)
+   {'body': {'info': {'_pypi_hidden': False,
+                      '_pypi_ordering': 12,
+                      'classifiers': [...],
+                      'download_url': 'UNKNOWN',
+                      'home_page': 'http://docs.python.org/py3k/library/configparser.html',
+                      'keywords': 'configparser ini parsing conf cfg configuration file',
+                      'license': 'MIT',
+                      'name': 'configparser',
+                      'package_url': 'http://pypi.python.org/pypi/configparser',
+                      'platform': 'any',
+                      'release_url': 'http://pypi.python.org/pypi/configparser/3.2.0r3',
+                      'requires_python': None,
+                      'stable_version': None,
+                      'summary': 'This library brings the updated configparser from Python 3.2+ to Python 2.6-2.7.',
+                      'version': '3.2.0r3'},
+           'urls': [{...}]},
+   'headers': [('Date', 'Sat, 14 May 2011 12:48:52 GMT'),
+               ('Server', 'Apache/2.2.16 (Debian)'),
+               ('Content-Disposition', 'inline'),
+               ('Connection', 'close'),
+               ('Transfer-Encoding', 'chunked'),
+               ('Content-Type', 'application/json; charset="UTF-8"')]}
+
+Additionally, maximum *width* can be suggested. If a long object cannot be
+split, the specified width will be exceeded::
+
+   >>> pprint.pprint(result['headers'], width=30)
+   [('Date',
+     'Sat, 14 May 2011 12:48:52 GMT'),
+    ('Server',
+     'Apache/2.2.16 (Debian)'),
+    ('Content-Disposition',
+     'inline'),
+    ('Connection', 'close'),
+    ('Transfer-Encoding',
+     'chunked'),
+    ('Content-Type',
+     'application/json; charset="UTF-8"')]
diff --git a/Lib/idlelib/NEWS.txt b/Lib/idlelib/NEWS.txt
index 18a2b82d725..0a4f98e9fba 100644
--- a/Lib/idlelib/NEWS.txt
+++ b/Lib/idlelib/NEWS.txt
@@ -3,6 +3,8 @@ What's New in IDLE 3.2.1?
 
 *Release date: 15-May-11*
 
+- Issue #6378: Further adjust idle.bat to start associated Python
+
 - Issue #11896: Save on Close failed despite selecting "Yes" in dialog.
 
 - Issue #1028: Ctrl-space binding to show completions was causing IDLE to exit.
@@ -63,7 +65,7 @@ What's New in IDLE 2.7? (UNRELEASED, but merged into 3.1 releases above.)
   extract port from command line when warnings are present.
 
 - Tk 8.5 Text widget requires 'wordprocessor' tabstyle attr to handle
-  mixed space/tab properly. Issue 5120, patch by Guilherme Polo.
+  mixed space/tab properly. Issue 5129, patch by Guilherme Polo.
 
 - Issue #3549: On MacOS the preferences menu was not present
 
diff --git a/Lib/idlelib/idle.bat b/Lib/idlelib/idle.bat
index cc653dc1c88..e77b96e9b51 100755
--- a/Lib/idlelib/idle.bat
+++ b/Lib/idlelib/idle.bat
@@ -1,4 +1,4 @@
 @echo off
 rem Start IDLE using the appropriate Python interpreter
 set CURRDIR=%~dp0
-start "%CURRDIR%..\..\pythonw.exe" "%CURRDIR%idle.pyw" %1 %2 %3 %4 %5 %6 %7 %8 %9
+start "IDLE" "%CURRDIR%..\..\pythonw.exe" "%CURRDIR%idle.pyw" %1 %2 %3 %4 %5 %6 %7 %8 %9
diff --git a/Lib/json/decoder.py b/Lib/json/decoder.py
index a19cf0f18cb..3174e31315f 100644
--- a/Lib/json/decoder.py
+++ b/Lib/json/decoder.py
@@ -5,7 +5,7 @@ import re
 import sys
 import struct
 
-from json.scanner import make_scanner
+from json import scanner
 try:
     from _json import scanstring as c_scanstring
 except ImportError:
@@ -340,7 +340,7 @@ class JSONDecoder(object):
         self.parse_array = JSONArray
         self.parse_string = scanstring
         self.memo = {}
-        self.scan_once = make_scanner(self)
+        self.scan_once = scanner.make_scanner(self)
 
 
     def decode(self, s, _w=WHITESPACE.match):
diff --git a/Lib/test/json_tests/__init__.py b/Lib/test/json_tests/__init__.py
index 4977468e47a..779c7a46b3d 100644
--- a/Lib/test/json_tests/__init__.py
+++ b/Lib/test/json_tests/__init__.py
@@ -1,7 +1,46 @@
 import os
 import sys
-import unittest
+import json
 import doctest
+import unittest
+
+from test import support
+
+# import json with and without accelerations
+cjson = support.import_fresh_module('json', fresh=['_json'])
+pyjson = support.import_fresh_module('json', blocked=['_json'])
+
+# create two base classes that will be used by the other tests
+class PyTest(unittest.TestCase):
+    json = pyjson
+    loads = staticmethod(pyjson.loads)
+    dumps = staticmethod(pyjson.dumps)
+
+@unittest.skipUnless(cjson, 'requires _json')
+class CTest(unittest.TestCase):
+    if cjson is not None:
+        json = cjson
+        loads = staticmethod(cjson.loads)
+        dumps = staticmethod(cjson.dumps)
+
+# test PyTest and CTest checking if the functions come from the right module
+class TestPyTest(PyTest):
+    def test_pyjson(self):
+        self.assertEqual(self.json.scanner.make_scanner.__module__,
+                         'json.scanner')
+        self.assertEqual(self.json.decoder.scanstring.__module__,
+                         'json.decoder')
+        self.assertEqual(self.json.encoder.encode_basestring_ascii.__module__,
+                         'json.encoder')
+
+class TestCTest(CTest):
+    def test_cjson(self):
+        self.assertEqual(self.json.scanner.make_scanner.__module__, '_json')
+        self.assertEqual(self.json.decoder.scanstring.__module__, '_json')
+        self.assertEqual(self.json.encoder.c_make_encoder.__module__, '_json')
+        self.assertEqual(self.json.encoder.encode_basestring_ascii.__module__,
+                         '_json')
+
 
 here = os.path.dirname(__file__)
 
@@ -17,12 +56,11 @@ def test_suite():
     return suite
 
 def additional_tests():
-    import json
-    import json.encoder
-    import json.decoder
     suite = unittest.TestSuite()
     for mod in (json, json.encoder, json.decoder):
         suite.addTest(doctest.DocTestSuite(mod))
+    suite.addTest(TestPyTest('test_pyjson'))
+    suite.addTest(TestCTest('test_cjson'))
     return suite
 
 def main():
diff --git a/Lib/test/json_tests/test_decode.py b/Lib/test/json_tests/test_decode.py
index 07dadfe26fc..9fbaa3bdf89 100644
--- a/Lib/test/json_tests/test_decode.py
+++ b/Lib/test/json_tests/test_decode.py
@@ -1,55 +1,38 @@
 import decimal
-from unittest import TestCase
 from io import StringIO
-from contextlib import contextmanager
-
-import json
-import json.decoder
-import json.scanner
 from collections import OrderedDict
+from test.json_tests import PyTest, CTest
 
 
-@contextmanager
-def use_python_scanner():
-    py_scanner = json.scanner.py_make_scanner
-    old_scanner = json.decoder.make_scanner
-    json.decoder.make_scanner = py_scanner
-    try:
-        yield
-    finally:
-        json.decoder.make_scanner = old_scanner
-
-
-class TestDecode(TestCase):
+class TestDecode:
     def test_decimal(self):
-        rval = json.loads('1.1', parse_float=decimal.Decimal)
+        rval = self.loads('1.1', parse_float=decimal.Decimal)
         self.assertTrue(isinstance(rval, decimal.Decimal))
         self.assertEqual(rval, decimal.Decimal('1.1'))
 
     def test_float(self):
-        rval = json.loads('1', parse_int=float)
+        rval = self.loads('1', parse_int=float)
         self.assertTrue(isinstance(rval, float))
         self.assertEqual(rval, 1.0)
 
     def test_empty_objects(self):
-        self.assertEqual(json.loads('{}'), {})
-        self.assertEqual(json.loads('[]'), [])
-        self.assertEqual(json.loads('""'), "")
+        self.assertEqual(self.loads('{}'), {})
+        self.assertEqual(self.loads('[]'), [])
+        self.assertEqual(self.loads('""'), "")
 
     def test_object_pairs_hook(self):
         s = '{"xkd":1, "kcw":2, "art":3, "hxm":4, "qrt":5, "pad":6, "hoy":7}'
         p = [("xkd", 1), ("kcw", 2), ("art", 3), ("hxm", 4),
              ("qrt", 5), ("pad", 6), ("hoy", 7)]
-        self.assertEqual(json.loads(s), eval(s))
-        self.assertEqual(json.loads(s, object_pairs_hook = lambda x: x), p)
-        self.assertEqual(json.load(StringIO(s),
-                                   object_pairs_hook=lambda x: x), p)
-        od = json.loads(s, object_pairs_hook = OrderedDict)
+        self.assertEqual(self.loads(s), eval(s))
+        self.assertEqual(self.loads(s, object_pairs_hook = lambda x: x), p)
+        self.assertEqual(self.json.load(StringIO(s),
+                                        object_pairs_hook=lambda x: x), p)
+        od = self.loads(s, object_pairs_hook = OrderedDict)
         self.assertEqual(od, OrderedDict(p))
         self.assertEqual(type(od), OrderedDict)
         # the object_pairs_hook takes priority over the object_hook
-        self.assertEqual(json.loads(s,
-                                    object_pairs_hook = OrderedDict,
+        self.assertEqual(self.loads(s, object_pairs_hook = OrderedDict,
                                     object_hook = lambda x: None),
                          OrderedDict(p))
 
@@ -57,7 +40,7 @@ class TestDecode(TestCase):
         # Several optimizations were made that skip over calls to
         # the whitespace regex, so this test is designed to try and
         # exercise the uncommon cases. The array cases are already covered.
-        rval = json.loads('{   "key"    :    "value"    ,  "k":"v"    }')
+        rval = self.loads('{   "key"    :    "value"    ,  "k":"v"    }')
         self.assertEqual(rval, {"key":"value", "k":"v"})
 
     def check_keys_reuse(self, source, loads):
@@ -68,7 +51,9 @@ class TestDecode(TestCase):
 
     def test_keys_reuse(self):
         s = '[{"a_key": 1, "b_\xe9": 2}, {"a_key": 3, "b_\xe9": 4}]'
-        self.check_keys_reuse(s, json.loads)
-        # Disabled: the pure Python version of json simply doesn't work
-        with use_python_scanner():
-            self.check_keys_reuse(s, json.decoder.JSONDecoder().decode)
+        self.check_keys_reuse(s, self.loads)
+        self.check_keys_reuse(s, self.json.decoder.JSONDecoder().decode)
+
+
+class TestPyDecode(TestDecode, PyTest): pass
+class TestCDecode(TestDecode, CTest): pass
diff --git a/Lib/test/json_tests/test_default.py b/Lib/test/json_tests/test_default.py
index 6a03eeb834d..672c753fbf7 100644
--- a/Lib/test/json_tests/test_default.py
+++ b/Lib/test/json_tests/test_default.py
@@ -1,9 +1,12 @@
-from unittest import TestCase
+from test.json_tests import PyTest, CTest
 
-import json
 
-class TestDefault(TestCase):
+class TestDefault:
     def test_default(self):
         self.assertEqual(
-            json.dumps(type, default=repr),
-            json.dumps(repr(type)))
+            self.dumps(type, default=repr),
+            self.dumps(repr(type)))
+
+
+class TestPyDefault(TestDefault, PyTest): pass
+class TestCDefault(TestDefault, CTest): pass
diff --git a/Lib/test/json_tests/test_dump.py b/Lib/test/json_tests/test_dump.py
index 8df234b819c..083c11f08c8 100644
--- a/Lib/test/json_tests/test_dump.py
+++ b/Lib/test/json_tests/test_dump.py
@@ -1,21 +1,24 @@
-from unittest import TestCase
 from io import StringIO
+from test.json_tests import PyTest, CTest
 
-import json
 
-class TestDump(TestCase):
+class TestDump:
     def test_dump(self):
         sio = StringIO()
-        json.dump({}, sio)
+        self.json.dump({}, sio)
         self.assertEqual(sio.getvalue(), '{}')
 
     def test_dumps(self):
-        self.assertEqual(json.dumps({}), '{}')
+        self.assertEqual(self.dumps({}), '{}')
 
     def test_encode_truefalse(self):
-        self.assertEqual(json.dumps(
+        self.assertEqual(self.dumps(
                  {True: False, False: True}, sort_keys=True),
                  '{"false": true, "true": false}')
-        self.assertEqual(json.dumps(
+        self.assertEqual(self.dumps(
                 {2: 3.0, 4.0: 5, False: 1, 6: True}, sort_keys=True),
                 '{"false": 1, "2": 3.0, "4.0": 5, "6": true}')
+
+
+class TestPyDump(TestDump, PyTest): pass
+class TestCDump(TestDump, CTest): pass
diff --git a/Lib/test/json_tests/test_encode_basestring_ascii.py b/Lib/test/json_tests/test_encode_basestring_ascii.py
index 4fddd121c6f..bfca69d18db 100644
--- a/Lib/test/json_tests/test_encode_basestring_ascii.py
+++ b/Lib/test/json_tests/test_encode_basestring_ascii.py
@@ -1,8 +1,6 @@
-from unittest import TestCase
-
-import json.encoder
-from json import dumps
 from collections import OrderedDict
+from test.json_tests import PyTest, CTest
+
 
 CASES = [
     ('/\\"\ucafe\ubabe\uab98\ufcde\ubcda\uef4a\x08\x0c\n\r\t`1~!@#$%^&*()_+-=[]{}|;:\',./<>?', '"/\\\\\\"\\ucafe\\ubabe\\uab98\\ufcde\\ubcda\\uef4a\\b\\f\\n\\r\\t`1~!@#$%^&*()_+-=[]{}|;:\',./<>?"'),
@@ -21,19 +19,11 @@ CASES = [
     ('\u0123\u4567\u89ab\ucdef\uabcd\uef4a', '"\\u0123\\u4567\\u89ab\\ucdef\\uabcd\\uef4a"'),
 ]
 
-class TestEncodeBaseStringAscii(TestCase):
-    def test_py_encode_basestring_ascii(self):
-        self._test_encode_basestring_ascii(json.encoder.py_encode_basestring_ascii)
-
-    def test_c_encode_basestring_ascii(self):
-        if not json.encoder.c_encode_basestring_ascii:
-            return
-        self._test_encode_basestring_ascii(json.encoder.c_encode_basestring_ascii)
-
-    def _test_encode_basestring_ascii(self, encode_basestring_ascii):
-        fname = encode_basestring_ascii.__name__
+class TestEncodeBasestringAscii:
+    def test_encode_basestring_ascii(self):
+        fname = self.json.encoder.encode_basestring_ascii.__name__
         for input_string, expect in CASES:
-            result = encode_basestring_ascii(input_string)
+            result = self.json.encoder.encode_basestring_ascii(input_string)
             self.assertEqual(result, expect,
                 '{0!r} != {1!r} for {2}({3!r})'.format(
                     result, expect, fname, input_string))
@@ -41,10 +31,14 @@ class TestEncodeBaseStringAscii(TestCase):
     def test_ordered_dict(self):
         # See issue 6105
         items = [('one', 1), ('two', 2), ('three', 3), ('four', 4), ('five', 5)]
-        s = json.dumps(OrderedDict(items))
+        s = self.dumps(OrderedDict(items))
         self.assertEqual(s, '{"one": 1, "two": 2, "three": 3, "four": 4, "five": 5}')
 
     def test_sorted_dict(self):
         items = [('one', 1), ('two', 2), ('three', 3), ('four', 4), ('five', 5)]
-        s = json.dumps(dict(items), sort_keys=True)
+        s = self.dumps(dict(items), sort_keys=True)
         self.assertEqual(s, '{"five": 5, "four": 4, "one": 1, "three": 3, "two": 2}')
+
+
+class TestPyEncodeBasestringAscii(TestEncodeBasestringAscii, PyTest): pass
+class TestCEncodeBasestringAscii(TestEncodeBasestringAscii, CTest): pass
diff --git a/Lib/test/json_tests/test_fail.py b/Lib/test/json_tests/test_fail.py
index 9768edf19a8..fcff1d4d410 100644
--- a/Lib/test/json_tests/test_fail.py
+++ b/Lib/test/json_tests/test_fail.py
@@ -1,6 +1,4 @@
-from unittest import TestCase
-
-import json
+from test.json_tests import PyTest, CTest
 
 # Fri Dec 30 18:57:26 2005
 JSONDOCS = [
@@ -61,15 +59,15 @@ SKIPS = {
     18: "spec doesn't specify any nesting limitations",
 }
 
-class TestFail(TestCase):
+class TestFail:
     def test_failures(self):
         for idx, doc in enumerate(JSONDOCS):
             idx = idx + 1
             if idx in SKIPS:
-                json.loads(doc)
+                self.loads(doc)
                 continue
             try:
-                json.loads(doc)
+                self.loads(doc)
             except ValueError:
                 pass
             else:
@@ -79,7 +77,11 @@ class TestFail(TestCase):
         data = {'a' : 1, (1, 2) : 2}
 
         #This is for c encoder
-        self.assertRaises(TypeError, json.dumps, data)
+        self.assertRaises(TypeError, self.dumps, data)
 
         #This is for python encoder
-        self.assertRaises(TypeError, json.dumps, data, indent=True)
+        self.assertRaises(TypeError, self.dumps, data, indent=True)
+
+
+class TestPyFail(TestFail, PyTest): pass
+class TestCFail(TestFail, CTest): pass
diff --git a/Lib/test/json_tests/test_float.py b/Lib/test/json_tests/test_float.py
index ca4a506db4d..a3441cf0435 100644
--- a/Lib/test/json_tests/test_float.py
+++ b/Lib/test/json_tests/test_float.py
@@ -1,15 +1,18 @@
 import math
-from unittest import TestCase
+from test.json_tests import PyTest, CTest
 
-import json
 
-class TestFloat(TestCase):
+class TestFloat:
     def test_floats(self):
         for num in [1617161771.7650001, math.pi, math.pi**100, math.pi**-100, 3.1]:
-            self.assertEqual(float(json.dumps(num)), num)
-            self.assertEqual(json.loads(json.dumps(num)), num)
+            self.assertEqual(float(self.dumps(num)), num)
+            self.assertEqual(self.loads(self.dumps(num)), num)
 
     def test_ints(self):
         for num in [1, 1<<32, 1<<64]:
-            self.assertEqual(json.dumps(num), str(num))
-            self.assertEqual(int(json.dumps(num)), num)
+            self.assertEqual(self.dumps(num), str(num))
+            self.assertEqual(int(self.dumps(num)), num)
+
+
+class TestPyFloat(TestFloat, PyTest): pass
+class TestCFloat(TestFloat, CTest): pass
diff --git a/Lib/test/json_tests/test_indent.py b/Lib/test/json_tests/test_indent.py
index 692a494cfe5..4c706463396 100644
--- a/Lib/test/json_tests/test_indent.py
+++ b/Lib/test/json_tests/test_indent.py
@@ -1,10 +1,9 @@
-from unittest import TestCase
-
-import json
 import textwrap
 from io import StringIO
+from test.json_tests import PyTest, CTest
 
-class TestIndent(TestCase):
+
+class TestIndent:
     def test_indent(self):
         h = [['blorpie'], ['whoops'], [], 'd-shtaeou', 'd-nthiouh', 'i-vhbjkhnth',
              {'nifty': 87}, {'field': 'yes', 'morefield': False} ]
@@ -30,14 +29,13 @@ class TestIndent(TestCase):
         \t}
         ]""")
 
+        d1 = self.dumps(h)
+        d2 = self.dumps(h, indent=2, sort_keys=True, separators=(',', ': '))
+        d3 = self.dumps(h, indent='\t', sort_keys=True, separators=(',', ': '))
 
-        d1 = json.dumps(h)
-        d2 = json.dumps(h, indent=2, sort_keys=True, separators=(',', ': '))
-        d3 = json.dumps(h, indent='\t', sort_keys=True, separators=(',', ': '))
-
-        h1 = json.loads(d1)
-        h2 = json.loads(d2)
-        h3 = json.loads(d3)
+        h1 = self.loads(d1)
+        h2 = self.loads(d2)
+        h3 = self.loads(d3)
 
         self.assertEqual(h1, h)
         self.assertEqual(h2, h)
@@ -48,14 +46,18 @@ class TestIndent(TestCase):
     def test_indent0(self):
         h = {3: 1}
         def check(indent, expected):
-            d1 = json.dumps(h, indent=indent)
+            d1 = self.dumps(h, indent=indent)
             self.assertEqual(d1, expected)
 
             sio = StringIO()
-            json.dump(h, sio, indent=indent)
+            self.json.dump(h, sio, indent=indent)
             self.assertEqual(sio.getvalue(), expected)
 
         # indent=0 should emit newlines
         check(0, '{\n"3": 1\n}')
         # indent=None is more compact
         check(None, '{"3": 1}')
+
+
+class TestPyIndent(TestIndent, PyTest): pass
+class TestCIndent(TestIndent, CTest): pass
diff --git a/Lib/test/json_tests/test_pass1.py b/Lib/test/json_tests/test_pass1.py
index 719c1137590..036a2e414cb 100644
--- a/Lib/test/json_tests/test_pass1.py
+++ b/Lib/test/json_tests/test_pass1.py
@@ -1,6 +1,5 @@
-from unittest import TestCase
+from test.json_tests import PyTest, CTest
 
-import json
 
 # from http://json.org/JSON_checker/test/pass1.json
 JSON = r'''
@@ -62,15 +61,19 @@ JSON = r'''
 ,"rosebud"]
 '''
 
-class TestPass1(TestCase):
+class TestPass1:
     def test_parse(self):
         # test in/out equivalence and parsing
-        res = json.loads(JSON)
-        out = json.dumps(res)
-        self.assertEqual(res, json.loads(out))
+        res = self.loads(JSON)
+        out = self.dumps(res)
+        self.assertEqual(res, self.loads(out))
         try:
-            json.dumps(res, allow_nan=False)
+            self.dumps(res, allow_nan=False)
         except ValueError:
             pass
         else:
             self.fail("23456789012E666 should be out of range")
+
+
+class TestPyPass1(TestPass1, PyTest): pass
+class TestCPass1(TestPass1, CTest): pass
diff --git a/Lib/test/json_tests/test_pass2.py b/Lib/test/json_tests/test_pass2.py
index 379117e9055..eee6383382c 100644
--- a/Lib/test/json_tests/test_pass2.py
+++ b/Lib/test/json_tests/test_pass2.py
@@ -1,14 +1,18 @@
-from unittest import TestCase
-import json
+from test.json_tests import PyTest, CTest
+
 
 # from http://json.org/JSON_checker/test/pass2.json
 JSON = r'''
 [[[[[[[[[[[[[[[[[[["Not too deep"]]]]]]]]]]]]]]]]]]]
 '''
 
-class TestPass2(TestCase):
+class TestPass2:
     def test_parse(self):
         # test in/out equivalence and parsing
-        res = json.loads(JSON)
-        out = json.dumps(res)
-        self.assertEqual(res, json.loads(out))
+        res = self.loads(JSON)
+        out = self.dumps(res)
+        self.assertEqual(res, self.loads(out))
+
+
+class TestPyPass2(TestPass2, PyTest): pass
+class TestCPass2(TestPass2, CTest): pass
diff --git a/Lib/test/json_tests/test_pass3.py b/Lib/test/json_tests/test_pass3.py
index 9151c4321c5..228eee8adb9 100644
--- a/Lib/test/json_tests/test_pass3.py
+++ b/Lib/test/json_tests/test_pass3.py
@@ -1,6 +1,5 @@
-from unittest import TestCase
+from test.json_tests import PyTest, CTest
 
-import json
 
 # from http://json.org/JSON_checker/test/pass3.json
 JSON = r'''
@@ -12,9 +11,14 @@ JSON = r'''
 }
 '''
 
-class TestPass3(TestCase):
+
+class TestPass3:
     def test_parse(self):
         # test in/out equivalence and parsing
-        res = json.loads(JSON)
-        out = json.dumps(res)
-        self.assertEqual(res, json.loads(out))
+        res = self.loads(JSON)
+        out = self.dumps(res)
+        self.assertEqual(res, self.loads(out))
+
+
+class TestPyPass3(TestPass3, PyTest): pass
+class TestCPass3(TestPass3, CTest): pass
diff --git a/Lib/test/json_tests/test_recursion.py b/Lib/test/json_tests/test_recursion.py
index ab5f213711f..192ed9cf40c 100644
--- a/Lib/test/json_tests/test_recursion.py
+++ b/Lib/test/json_tests/test_recursion.py
@@ -1,33 +1,16 @@
-from unittest import TestCase
+from test.json_tests import PyTest, CTest
 
-import json
 
 class JSONTestObject:
     pass
 
 
-class RecursiveJSONEncoder(json.JSONEncoder):
-    recurse = False
-    def default(self, o):
-        if o is JSONTestObject:
-            if self.recurse:
-                return [JSONTestObject]
-            else:
-                return 'JSONTestObject'
-        return json.JSONEncoder.default(o)
-
-class EndlessJSONEncoder(json.JSONEncoder):
-    def default(self, o):
-        """If check_circular is False, this will keep adding another list."""
-        return [o]
-
-
-class TestRecursion(TestCase):
+class TestRecursion:
     def test_listrecursion(self):
         x = []
         x.append(x)
         try:
-            json.dumps(x)
+            self.dumps(x)
         except ValueError:
             pass
         else:
@@ -36,7 +19,7 @@ class TestRecursion(TestCase):
         y = [x]
         x.append(y)
         try:
-            json.dumps(x)
+            self.dumps(x)
         except ValueError:
             pass
         else:
@@ -44,13 +27,13 @@ class TestRecursion(TestCase):
         y = []
         x = [y, y]
         # ensure that the marker is cleared
-        json.dumps(x)
+        self.dumps(x)
 
     def test_dictrecursion(self):
         x = {}
         x["test"] = x
         try:
-            json.dumps(x)
+            self.dumps(x)
         except ValueError:
             pass
         else:
@@ -58,9 +41,19 @@ class TestRecursion(TestCase):
         x = {}
         y = {"a": x, "b": x}
         # ensure that the marker is cleared
-        json.dumps(x)
+        self.dumps(x)
 
     def test_defaultrecursion(self):
+        class RecursiveJSONEncoder(self.json.JSONEncoder):
+            recurse = False
+            def default(self, o):
+                if o is JSONTestObject:
+                    if self.recurse:
+                        return [JSONTestObject]
+                    else:
+                        return 'JSONTestObject'
+                return pyjson.JSONEncoder.default(o)
+
         enc = RecursiveJSONEncoder()
         self.assertEqual(enc.encode(JSONTestObject), '"JSONTestObject"')
         enc.recurse = True
@@ -76,11 +69,11 @@ class TestRecursion(TestCase):
         # test that loading highly-nested objects doesn't segfault when C
         # accelerations are used. See #12017
         with self.assertRaises(RuntimeError):
-            json.loads('{"a":' * 100000 + '1' + '}' * 100000)
+            self.loads('{"a":' * 100000 + '1' + '}' * 100000)
         with self.assertRaises(RuntimeError):
-            json.loads('{"a":' * 100000 + '[1]' + '}' * 100000)
+            self.loads('{"a":' * 100000 + '[1]' + '}' * 100000)
         with self.assertRaises(RuntimeError):
-            json.loads('[' * 100000 + '1' + ']' * 100000)
+            self.loads('[' * 100000 + '1' + ']' * 100000)
 
     def test_highly_nested_objects_encoding(self):
         # See #12051
@@ -88,11 +81,20 @@ class TestRecursion(TestCase):
         for x in range(100000):
             l, d = [l], {'k':d}
         with self.assertRaises(RuntimeError):
-            json.dumps(l)
+            self.dumps(l)
         with self.assertRaises(RuntimeError):
-            json.dumps(d)
+            self.dumps(d)
 
     def test_endless_recursion(self):
         # See #12051
+        class EndlessJSONEncoder(self.json.JSONEncoder):
+            def default(self, o):
+                """If check_circular is False, this will keep adding another list."""
+                return [o]
+
         with self.assertRaises(RuntimeError):
             EndlessJSONEncoder(check_circular=False).encode(5j)
+
+
+class TestPyRecursion(TestRecursion, PyTest): pass
+class TestCRecursion(TestRecursion, CTest): pass
diff --git a/Lib/test/json_tests/test_scanstring.py b/Lib/test/json_tests/test_scanstring.py
index abd325324dd..f82cdeead3c 100644
--- a/Lib/test/json_tests/test_scanstring.py
+++ b/Lib/test/json_tests/test_scanstring.py
@@ -1,24 +1,10 @@
 import sys
-from unittest import TestCase, skipUnless
+from test.json_tests import PyTest, CTest
 
-import json
-import json.decoder
 
-try:
-    import _json
-except ImportError:
-    _json = None
-
-class TestScanString(TestCase):
-    def test_py_scanstring(self):
-        self._test_scanstring(json.decoder.py_scanstring)
-
-    @skipUnless(_json, 'test requires the _json module')
-    def test_c_scanstring(self):
-        if json.decoder.c_scanstring is not None:
-            self._test_scanstring(json.decoder.c_scanstring)
-
-    def _test_scanstring(self, scanstring):
+class TestScanstring:
+    def test_scanstring(self):
+        scanstring = self.json.decoder.scanstring
         self.assertEqual(
             scanstring('"z\\ud834\\udd20x"', 1, True),
             ('z\U0001d120x', 16))
@@ -109,4 +95,9 @@ class TestScanString(TestCase):
             ('Bad value', 12))
 
     def test_overflow(self):
-        self.assertRaises(OverflowError, json.decoder.scanstring, b"xxx", sys.maxsize+1)
+        with self.assertRaises(OverflowError):
+            self.json.decoder.scanstring(b"xxx", sys.maxsize+1)
+
+
+class TestPyScanstring(TestScanstring, PyTest): pass
+class TestCScanstring(TestScanstring, CTest): pass
diff --git a/Lib/test/json_tests/test_separators.py b/Lib/test/json_tests/test_separators.py
index d5b92bd65d1..a01b38c0807 100644
--- a/Lib/test/json_tests/test_separators.py
+++ b/Lib/test/json_tests/test_separators.py
@@ -1,10 +1,8 @@
 import textwrap
-from unittest import TestCase
-
-import json
+from test.json_tests import PyTest, CTest
 
 
-class TestSeparators(TestCase):
+class TestSeparators:
     def test_separators(self):
         h = [['blorpie'], ['whoops'], [], 'd-shtaeou', 'd-nthiouh', 'i-vhbjkhnth',
              {'nifty': 87}, {'field': 'yes', 'morefield': False} ]
@@ -31,12 +29,16 @@ class TestSeparators(TestCase):
         ]""")
 
 
-        d1 = json.dumps(h)
-        d2 = json.dumps(h, indent=2, sort_keys=True, separators=(' ,', ' : '))
+        d1 = self.dumps(h)
+        d2 = self.dumps(h, indent=2, sort_keys=True, separators=(' ,', ' : '))
 
-        h1 = json.loads(d1)
-        h2 = json.loads(d2)
+        h1 = self.loads(d1)
+        h2 = self.loads(d2)
 
         self.assertEqual(h1, h)
         self.assertEqual(h2, h)
         self.assertEqual(d2, expect)
+
+
+class TestPySeparators(TestSeparators, PyTest): pass
+class TestCSeparators(TestSeparators, CTest): pass
diff --git a/Lib/test/json_tests/test_speedups.py b/Lib/test/json_tests/test_speedups.py
index b7c141f7f6f..5c24c0580b0 100644
--- a/Lib/test/json_tests/test_speedups.py
+++ b/Lib/test/json_tests/test_speedups.py
@@ -1,29 +1,24 @@
-from unittest import TestCase, skipUnless
+from test.json_tests import CTest
 
-from json import decoder, encoder, scanner
 
-try:
-    import _json
-except ImportError:
-    _json = None
-
-@skipUnless(_json, 'test requires the _json module')
-class TestSpeedups(TestCase):
+class TestSpeedups(CTest):
     def test_scanstring(self):
-        self.assertEqual(decoder.scanstring.__module__, "_json")
-        self.assertIs(decoder.scanstring, decoder.c_scanstring)
+        self.assertEqual(self.json.decoder.scanstring.__module__, "_json")
+        self.assertIs(self.json.decoder.scanstring, self.json.decoder.c_scanstring)
 
     def test_encode_basestring_ascii(self):
-        self.assertEqual(encoder.encode_basestring_ascii.__module__, "_json")
-        self.assertIs(encoder.encode_basestring_ascii,
-                      encoder.c_encode_basestring_ascii)
+        self.assertEqual(self.json.encoder.encode_basestring_ascii.__module__,
+                         "_json")
+        self.assertIs(self.json.encoder.encode_basestring_ascii,
+                      self.json.encoder.c_encode_basestring_ascii)
 
-class TestDecode(TestCase):
+
+class TestDecode(CTest):
     def test_make_scanner(self):
-        self.assertRaises(AttributeError, scanner.c_make_scanner, 1)
+        self.assertRaises(AttributeError, self.json.scanner.c_make_scanner, 1)
 
     def test_make_encoder(self):
-        self.assertRaises(TypeError, encoder.c_make_encoder,
+        self.assertRaises(TypeError, self.json.encoder.c_make_encoder,
             (True, False),
             b"\xCD\x7D\x3D\x4E\x12\x4C\xF9\x79\xD7\x52\xBA\x82\xF2\x27\x4A\x7D\xA0\xCA\x75",
             None)
diff --git a/Lib/test/json_tests/test_unicode.py b/Lib/test/json_tests/test_unicode.py
index e336c91fa92..f226aa6f03d 100644
--- a/Lib/test/json_tests/test_unicode.py
+++ b/Lib/test/json_tests/test_unicode.py
@@ -1,73 +1,75 @@
-from unittest import TestCase
-
-import json
 from collections import OrderedDict
+from test.json_tests import PyTest, CTest
 
-class TestUnicode(TestCase):
+
+class TestUnicode:
     # test_encoding1 and test_encoding2 from 2.x are irrelevant (only str
     # is supported as input, not bytes).
 
     def test_encoding3(self):
         u = '\N{GREEK SMALL LETTER ALPHA}\N{GREEK CAPITAL LETTER OMEGA}'
-        j = json.dumps(u)
+        j = self.dumps(u)
         self.assertEqual(j, '"\\u03b1\\u03a9"')
 
     def test_encoding4(self):
         u = '\N{GREEK SMALL LETTER ALPHA}\N{GREEK CAPITAL LETTER OMEGA}'
-        j = json.dumps([u])
+        j = self.dumps([u])
         self.assertEqual(j, '["\\u03b1\\u03a9"]')
 
     def test_encoding5(self):
         u = '\N{GREEK SMALL LETTER ALPHA}\N{GREEK CAPITAL LETTER OMEGA}'
-        j = json.dumps(u, ensure_ascii=False)
+        j = self.dumps(u, ensure_ascii=False)
         self.assertEqual(j, '"{0}"'.format(u))
 
     def test_encoding6(self):
         u = '\N{GREEK SMALL LETTER ALPHA}\N{GREEK CAPITAL LETTER OMEGA}'
-        j = json.dumps([u], ensure_ascii=False)
+        j = self.dumps([u], ensure_ascii=False)
         self.assertEqual(j, '["{0}"]'.format(u))
 
     def test_big_unicode_encode(self):
         u = '\U0001d120'
-        self.assertEqual(json.dumps(u), '"\\ud834\\udd20"')
-        self.assertEqual(json.dumps(u, ensure_ascii=False), '"\U0001d120"')
+        self.assertEqual(self.dumps(u), '"\\ud834\\udd20"')
+        self.assertEqual(self.dumps(u, ensure_ascii=False), '"\U0001d120"')
 
     def test_big_unicode_decode(self):
         u = 'z\U0001d120x'
-        self.assertEqual(json.loads('"' + u + '"'), u)
-        self.assertEqual(json.loads('"z\\ud834\\udd20x"'), u)
+        self.assertEqual(self.loads('"' + u + '"'), u)
+        self.assertEqual(self.loads('"z\\ud834\\udd20x"'), u)
 
     def test_unicode_decode(self):
         for i in range(0, 0xd7ff):
             u = chr(i)
             s = '"\\u{0:04x}"'.format(i)
-            self.assertEqual(json.loads(s), u)
+            self.assertEqual(self.loads(s), u)
 
     def test_unicode_preservation(self):
-        self.assertEqual(type(json.loads('""')), str)
-        self.assertEqual(type(json.loads('"a"')), str)
-        self.assertEqual(type(json.loads('["a"]')[0]), str)
+        self.assertEqual(type(self.loads('""')), str)
+        self.assertEqual(type(self.loads('"a"')), str)
+        self.assertEqual(type(self.loads('["a"]')[0]), str)
 
     def test_bytes_encode(self):
-        self.assertRaises(TypeError, json.dumps, b"hi")
-        self.assertRaises(TypeError, json.dumps, [b"hi"])
+        self.assertRaises(TypeError, self.dumps, b"hi")
+        self.assertRaises(TypeError, self.dumps, [b"hi"])
 
     def test_bytes_decode(self):
-        self.assertRaises(TypeError, json.loads, b'"hi"')
-        self.assertRaises(TypeError, json.loads, b'["hi"]')
+        self.assertRaises(TypeError, self.loads, b'"hi"')
+        self.assertRaises(TypeError, self.loads, b'["hi"]')
 
 
     def test_object_pairs_hook_with_unicode(self):
         s = '{"xkd":1, "kcw":2, "art":3, "hxm":4, "qrt":5, "pad":6, "hoy":7}'
         p = [("xkd", 1), ("kcw", 2), ("art", 3), ("hxm", 4),
              ("qrt", 5), ("pad", 6), ("hoy", 7)]
-        self.assertEqual(json.loads(s), eval(s))
-        self.assertEqual(json.loads(s, object_pairs_hook = lambda x: x), p)
-        od = json.loads(s, object_pairs_hook = OrderedDict)
+        self.assertEqual(self.loads(s), eval(s))
+        self.assertEqual(self.loads(s, object_pairs_hook = lambda x: x), p)
+        od = self.loads(s, object_pairs_hook = OrderedDict)
         self.assertEqual(od, OrderedDict(p))
         self.assertEqual(type(od), OrderedDict)
         # the object_pairs_hook takes priority over the object_hook
-        self.assertEqual(json.loads(s,
-                                    object_pairs_hook = OrderedDict,
+        self.assertEqual(self.loads(s, object_pairs_hook = OrderedDict,
                                     object_hook = lambda x: None),
                          OrderedDict(p))
+
+
+class TestPyUnicode(TestUnicode, PyTest): pass
+class TestCUnicode(TestUnicode, CTest): pass
diff --git a/Lib/test/support.py b/Lib/test/support.py
index cab366b09bd..0cc8c31c07f 100644
--- a/Lib/test/support.py
+++ b/Lib/test/support.py
@@ -37,6 +37,7 @@ __all__ = [
     "findfile", "sortdict", "check_syntax_error", "open_urlresource",
     "check_warnings", "CleanImport", "EnvironmentVarGuard",
     "TransientResource", "captured_output", "captured_stdout",
+    "captured_stdin", "captured_stderr",
     "time_out", "socket_peer_reset", "ioerror_peer_reset",
     "run_with_locale", 'temp_umask', "transient_internet",
     "set_memlimit", "bigmemtest", "bigaddrspacetest", "BasicTestRunner",
@@ -92,19 +93,15 @@ def import_module(name, deprecated=False):
 def _save_and_remove_module(name, orig_modules):
     """Helper function to save and remove a module from sys.modules
 
-       Return True if the module was in sys.modules, False otherwise.
        Raise ImportError if the module can't be imported."""
-    saved = True
-    try:
-        orig_modules[name] = sys.modules[name]
-    except KeyError:
-        # try to import the module and raise an error if it can't be imported
+    # try to import the module and raise an error if it can't be imported
+    if name not in sys.modules:
         __import__(name)
-        saved = False
-    else:
         del sys.modules[name]
-    return saved
-
+    for modname in list(sys.modules):
+        if modname == name or modname.startswith(name + '.'):
+            orig_modules[modname] = sys.modules[modname]
+            del sys.modules[modname]
 
 def _save_and_block_module(name, orig_modules):
     """Helper function to save and block a module in sys.modules
@@ -132,8 +129,8 @@ def import_fresh_module(name, fresh=(), blocked=(), deprecated=False):
 
     If deprecated is True, any module or package deprecation messages
     will be suppressed."""
-    # NOTE: test_heapq and test_warnings include extra sanity checks to make
-    # sure that this utility function is working as expected
+    # NOTE: test_heapq, test_json and test_warnings include extra sanity checks
+    # to make sure that this utility function is working as expected
     with _ignore_deprecated_imports(deprecated):
         # Keep track of modules saved for later restoration as well
         # as those which just need a blocking entry removed
@@ -895,14 +892,8 @@ def transient_internet(resource_name, *, timeout=30.0, errnos=()):
 
 @contextlib.contextmanager
 def captured_output(stream_name):
-    """Run the 'with' statement body using a StringIO object in place of a
-    specific attribute on the sys module.
-    Example use (with 'stream_name=stdout')::
-
-       with captured_stdout() as s:
-           print("hello")
-       assert s.getvalue() == "hello"
-    """
+    """Return a context manager used by captured_stdout/stdin/stderr
+    that temporarily replaces the sys stream *stream_name* with a StringIO."""
     import io
     orig_stdout = getattr(sys, stream_name)
     setattr(sys, stream_name, io.StringIO())
@@ -912,6 +903,12 @@ def captured_output(stream_name):
         setattr(sys, stream_name, orig_stdout)
 
 def captured_stdout():
+    """Capture the output of sys.stdout:
+
+       with captured_stdout() as s:
+           print("hello")
+       self.assertEqual(s.getvalue(), "hello")
+    """
     return captured_output("stdout")
 
 def captured_stderr():
@@ -920,6 +917,7 @@ def captured_stderr():
 def captured_stdin():
     return captured_output("stdin")
 
+
 def gc_collect():
     """Force as many objects as possible to be collected.
 
diff --git a/Lib/test/test_zlib.py b/Lib/test/test_zlib.py
index 9aafffa8d21..48d9f582cf4 100644
--- a/Lib/test/test_zlib.py
+++ b/Lib/test/test_zlib.py
@@ -193,6 +193,7 @@ class CompressTestCase(BaseCompressTestCase, unittest.TestCase):
         data = b'x' * size
         try:
             self.assertRaises(OverflowError, zlib.compress, data, 1)
+            self.assertRaises(OverflowError, zlib.decompress, data)
         finally:
             data = None
 
@@ -360,6 +361,15 @@ class CompressObjectTestCase(BaseCompressTestCase, unittest.TestCase):
         self.assertRaises(ValueError, dco.decompress, b"", -1)
         self.assertEqual(b'', dco.unconsumed_tail)
 
+    def test_clear_unconsumed_tail(self):
+        # Issue #12050: calling decompress() without providing max_length
+        # should clear the unconsumed_tail attribute.
+        cdata = b"x\x9cKLJ\x06\x00\x02M\x01"    # "abc"
+        dco = zlib.decompressobj()
+        ddata = dco.decompress(cdata, 1)
+        ddata += dco.decompress(dco.unconsumed_tail)
+        self.assertEqual(dco.unconsumed_tail, b"")
+
     def test_flushes(self):
         # Test flush() with the various options, using all the
         # different levels in order to provide more variations.
diff --git a/Misc/NEWS b/Misc/NEWS
index 5b014269e7f..309ea7b5c50 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -90,6 +90,9 @@ Core and Builtins
 Library
 -------
 
+- Issue #12050: zlib.decompressobj().decompress() now clears the unconsumed_tail
+  attribute when called without a max_length argument.
+
 - Issue #12062: Fix a flushing bug when doing a certain type of I/O sequence
   on a file opened in read+write mode (namely: reading, seeking a bit forward,
   writing, then seeking before the previous write but still within buffered
@@ -379,6 +382,8 @@ Extension Modules
 Tests
 -----
 
+- Issue #5723: Improve json tests to be executed with and without accelerations.
+
 - Issue #11873: Change regex in test_compileall to fix occasional failures when
   when the randomly generated temporary path happened to match the regex.
 
diff --git a/Modules/zlibmodule.c b/Modules/zlibmodule.c
index 206ef0c6d8c..fa07739a16f 100644
--- a/Modules/zlibmodule.c
+++ b/Modules/zlibmodule.c
@@ -116,7 +116,7 @@ PyZlib_compress(PyObject *self, PyObject *args)
 {
     PyObject *ReturnVal = NULL;
     Py_buffer pinput;
-    Byte *input, *output;
+    Byte *input, *output = NULL;
     unsigned int length;
     int level=Z_DEFAULT_COMPRESSION, err;
     z_stream zst;
@@ -127,20 +127,19 @@ PyZlib_compress(PyObject *self, PyObject *args)
 
     if (pinput.len > UINT_MAX) {
         PyErr_SetString(PyExc_OverflowError,
-            "size does not fit in an unsigned int");
-        return NULL;
+                        "Size does not fit in an unsigned int");
+        goto error;
     }
-    length = pinput.len;
     input = pinput.buf;
+    length = pinput.len;
 
     zst.avail_out = length + length/1000 + 12 + 1;
 
     output = (Byte*)malloc(zst.avail_out);
     if (output == NULL) {
-        PyBuffer_Release(&pinput);
         PyErr_SetString(PyExc_MemoryError,
                         "Can't allocate memory to compress data");
-        return NULL;
+        goto error;
     }
 
     /* Past the point of no return.  From here on out, we need to make sure
@@ -203,7 +202,7 @@ PyDoc_STRVAR(decompress__doc__,
 static PyObject *
 PyZlib_decompress(PyObject *self, PyObject *args)
 {
-    PyObject *result_str;
+    PyObject *result_str = NULL;
     Py_buffer pinput;
     Byte *input;
     unsigned int length;
@@ -218,11 +217,11 @@ PyZlib_decompress(PyObject *self, PyObject *args)
 
     if (pinput.len > UINT_MAX) {
         PyErr_SetString(PyExc_OverflowError,
-            "size does not fit in an unsigned int");
-        return NULL;
+                        "Size does not fit in an unsigned int");
+        goto error;
     }
-    length = pinput.len;
     input = pinput.buf;
+    length = pinput.len;
 
     if (r_strlen <= 0)
         r_strlen = 1;
@@ -230,10 +229,8 @@ PyZlib_decompress(PyObject *self, PyObject *args)
     zst.avail_in = length;
     zst.avail_out = r_strlen;
 
-    if (!(result_str = PyBytes_FromStringAndSize(NULL, r_strlen))) {
-        PyBuffer_Release(&pinput);
-        return NULL;
-    }
+    if (!(result_str = PyBytes_FromStringAndSize(NULL, r_strlen)))
+        goto error;
 
     zst.zalloc = (alloc_func)NULL;
     zst.zfree = (free_func)Z_NULL;
@@ -574,17 +571,22 @@ PyZlib_objdecompress(compobject *self, PyObject *args)
         Py_END_ALLOW_THREADS
     }
 
-    /* Not all of the compressed data could be accommodated in the output buffer
-       of specified size. Return the unconsumed tail in an attribute.*/
     if(max_length) {
+        /* Not all of the compressed data could be accommodated in a buffer of
+           the specified size. Return the unconsumed tail in an attribute. */
         Py_DECREF(self->unconsumed_tail);
         self->unconsumed_tail = PyBytes_FromStringAndSize((char *)self->zst.next_in,
                                                            self->zst.avail_in);
-        if(!self->unconsumed_tail) {
-            Py_DECREF(RetVal);
-            RetVal = NULL;
-            goto error;
-        }
+    }
+    else if (PyBytes_GET_SIZE(self->unconsumed_tail) > 0) {
+        /* All of the compressed data was consumed. Clear unconsumed_tail. */
+        Py_DECREF(self->unconsumed_tail);
+        self->unconsumed_tail = PyBytes_FromStringAndSize("", 0);
+    }
+    if (self->unconsumed_tail == NULL) {
+        Py_DECREF(RetVal);
+        RetVal = NULL;
+        goto error;
     }
 
     /* The end of the compressed data has been reached, so set the