diff --git a/Lib/json/decoder.py b/Lib/json/decoder.py
index a19cf0f..3174e31 100644
--- a/Lib/json/decoder.py
+++ b/Lib/json/decoder.py
@@ -5,7 +5,7 @@
 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 @@
         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 4977468..779c7a4 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 @@
     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 07dadfe..9fbaa3b 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 @@
         # 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 @@
 
     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 6a03eeb..672c753 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 8df234b..083c11f 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 4fddd12..bfca69d 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 @@
     ('\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 @@
     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 9768edf..fcff1d4 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 @@
     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 @@
         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 ca4a506..a3441cf 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 692a494..4c70646 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 @@
         \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 @@
     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 719c113..036a2e4 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 @@
 ,"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 379117e..eee6383 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 9151c43..228eee8 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 @@
 }
 '''
 
-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 ab5f213..192ed9c 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 @@
         y = [x]
         x.append(y)
         try:
-            json.dumps(x)
+            self.dumps(x)
         except ValueError:
             pass
         else:
@@ -44,13 +27,13 @@
         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 @@
         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 @@
         # 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 @@
         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 abd3253..f82cdee 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 @@
             ('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 d5b92bd..a01b38c 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 @@
         ]""")
 
 
-        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 b7c141f..5c24c05 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 e336c91..f226aa6 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 2a06661..bd35fde 100644
--- a/Lib/test/support.py
+++ b/Lib/test/support.py
@@ -128,8 +128,8 @@
 
     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
diff --git a/Misc/NEWS b/Misc/NEWS
index 5b01426..06fab03 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -379,6 +379,8 @@
 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.