bpo-40275: Use new test.support helper submodules in tests (GH-21169)

14 files changed, 348 insertions, 319 deletions

diff --git a/Lib/test/_test_multiprocessing.py b/Lib/test/_test_multiprocessing.py
index 5f65d96..6b4679f 100644
--- a/Lib/test/_test_multiprocessing.py
+++ b/Lib/test/_test_multiprocessing.py
@@ -27,12 +27,13 @@ import test.support
 import test.support.script_helper
 from test import support
 from test.support import hashlib_helper
+from test.support import import_helper
 from test.support import socket_helper
 from test.support import threading_helper
 
 
 # Skip tests if _multiprocessing wasn't built.
-_multiprocessing = test.support.import_module('_multiprocessing')
+_multiprocessing = import_helper.import_module('_multiprocessing')
 # Skip tests if sem_open implementation is broken.
 support.skip_if_broken_multiprocessing_synchronize()
 import threading
diff --git a/Lib/test/test_base64.py b/Lib/test/test_base64.py
index 1dbeac4..1f67e46 100644
--- a/Lib/test/test_base64.py
+++ b/Lib/test/test_base64.py
@@ -1,9 +1,9 @@
 import unittest
-from test import support
 import base64
 import binascii
 import os
 from array import array
+from test.support import os_helper
 from test.support import script_helper
 
 
@@ -647,8 +647,8 @@ class BaseXYTestCase(unittest.TestCase):
 
 class TestMain(unittest.TestCase):
     def tearDown(self):
-        if os.path.exists(support.TESTFN):
-            os.unlink(support.TESTFN)
+        if os.path.exists(os_helper.TESTFN):
+            os.unlink(os_helper.TESTFN)
 
     def get_output(self, *args):
         return script_helper.assert_python_ok('-m', 'base64', *args).out
@@ -662,9 +662,9 @@ class TestMain(unittest.TestCase):
         ))
 
     def test_encode_file(self):
-        with open(support.TESTFN, 'wb') as fp:
+        with open(os_helper.TESTFN, 'wb') as fp:
             fp.write(b'a\xffb\n')
-        output = self.get_output('-e', support.TESTFN)
+        output = self.get_output('-e', os_helper.TESTFN)
         self.assertEqual(output.rstrip(), b'Yf9iCg==')
 
     def test_encode_from_stdin(self):
@@ -674,9 +674,9 @@ class TestMain(unittest.TestCase):
         self.assertIsNone(err)
 
     def test_decode(self):
-        with open(support.TESTFN, 'wb') as fp:
+        with open(os_helper.TESTFN, 'wb') as fp:
             fp.write(b'Yf9iCg==')
-        output = self.get_output('-d', support.TESTFN)
+        output = self.get_output('-d', os_helper.TESTFN)
         self.assertEqual(output.rstrip(), b'a\xffb')
 
 if __name__ == '__main__':
diff --git a/Lib/test/test_bool.py b/Lib/test/test_bool.py
index 4c6fba4..7b3a385 100644
--- a/Lib/test/test_bool.py
+++ b/Lib/test/test_bool.py
@@ -2,6 +2,7 @@
 
 import unittest
 from test import support
+from test.support import os_helper
 
 import os
 
@@ -234,11 +235,11 @@ class BoolTest(unittest.TestCase):
 
     def test_fileclosed(self):
         try:
-            with open(support.TESTFN, "w") as f:
+            with open(os_helper.TESTFN, "w") as f:
                 self.assertIs(f.closed, False)
             self.assertIs(f.closed, True)
         finally:
-            os.remove(support.TESTFN)
+            os.remove(os_helper.TESTFN)
 
     def test_types(self):
         # types are always true.
diff --git a/Lib/test/test_dict_version.py b/Lib/test/test_dict_version.py
index b237865..8cdccad 100644
--- a/Lib/test/test_dict_version.py
+++ b/Lib/test/test_dict_version.py
@@ -2,11 +2,11 @@
 Test implementation of the PEP 509: dictionary versionning.
 """
 import unittest
-from test import support
+from test.support import import_helper
 
 # PEP 509 is implemented in CPython but other Python implementations
 # don't require to implement it
-_testcapi = support.import_module('_testcapi')
+_testcapi = import_helper.import_module('_testcapi')
 
 
 class DictVersionTests(unittest.TestCase):
diff --git a/Lib/test/test_grammar.py b/Lib/test/test_grammar.py
index ef7d1a1..a51452e 100644
--- a/Lib/test/test_grammar.py
+++ b/Lib/test/test_grammar.py
@@ -1,7 +1,8 @@
 # Python test set -- part 1, grammar.
 # This just tests whether the parser accepts them all.
 
-from test.support import check_syntax_error, check_syntax_warning
+from test.support import check_syntax_error
+from test.support.warnings_helper import check_syntax_warning
 import inspect
 import unittest
 import sys
@@ -276,7 +277,8 @@ class CNS:
 
 class GrammarTests(unittest.TestCase):
 
-    from test.support import check_syntax_error, check_syntax_warning
+    from test.support import check_syntax_error
+    from test.support.warnings_helper import check_syntax_warning
 
     # single_input: NEWLINE | simple_stmt | compound_stmt NEWLINE
     # XXX can't test in a script -- this rule is only used when interactive
diff --git a/Lib/test/test_iter.py b/Lib/test/test_iter.py
index 5243469..a7658b5 100644
--- a/Lib/test/test_iter.py
+++ b/Lib/test/test_iter.py
@@ -2,7 +2,8 @@
 
 import sys
 import unittest
-from test.support import run_unittest, TESTFN, unlink, cpython_only
+from test.support import run_unittest, cpython_only
+from test.support.os_helper import TESTFN, unlink
 from test.support import check_free_after_iterating, ALWAYS_EQ, NEVER_EQ
 import pickle
 import collections.abc
diff --git a/Lib/test/test_lzma.py b/Lib/test/test_lzma.py
index 0f3af27..c2427f8 100644
--- a/Lib/test/test_lzma.py
+++ b/Lib/test/test_lzma.py
@@ -9,7 +9,11 @@ from test import support
 import unittest
 
 from test.support import (
-    _4G, TESTFN, import_module, bigmemtest, run_unittest, unlink
+    _4G, bigmemtest, run_unittest
+)
+from test.support.import_helper import import_module
+from test.support.os_helper import (
+    TESTFN, unlink
 )
 
 lzma = import_module("lzma")
diff --git a/Lib/test/test_mailcap.py b/Lib/test/test_mailcap.py
index c08423c..51a0c7d 100644
--- a/Lib/test/test_mailcap.py
+++ b/Lib/test/test_mailcap.py
@@ -2,6 +2,7 @@ import mailcap
 import os
 import copy
 import test.support
+from test.support import os_helper
 import unittest
 
 # Location of mailcap file
@@ -74,7 +75,7 @@ class HelperFunctionTest(unittest.TestCase):
         self.assertIsInstance(mcfiles, list)
         for m in mcfiles:
             self.assertIsInstance(m, str)
-        with test.support.EnvironmentVarGuard() as env:
+        with os_helper.EnvironmentVarGuard() as env:
             # According to RFC 1524, if MAILCAPS env variable exists, use that
             # and only that.
             if "MAILCAPS" in env:
@@ -136,7 +137,7 @@ class GetcapsTest(unittest.TestCase):
         # Test mailcap.getcaps() using mock mailcap file in this dir.
         # Temporarily override any existing system mailcap file by pointing the
         # MAILCAPS environment variable to our mock file.
-        with test.support.EnvironmentVarGuard() as env:
+        with os_helper.EnvironmentVarGuard() as env:
             env["MAILCAPS"] = MAILCAPFILE
             caps = mailcap.getcaps()
             self.assertDictEqual(caps, MAILCAPDICT)
diff --git a/Lib/test/test_memoryview.py b/Lib/test/test_memoryview.py
index ca307d8..d7e3f0c 100644
--- a/Lib/test/test_memoryview.py
+++ b/Lib/test/test_memoryview.py
@@ -14,6 +14,8 @@ import io
 import copy
 import pickle
 
+from test.support import import_helper
+
 
 class AbstractMemoryTests:
     source_bytes = b"abcdef"
@@ -508,7 +510,7 @@ class ArrayMemorySliceSliceTest(unittest.TestCase,
 class OtherTest(unittest.TestCase):
     def test_ctypes_cast(self):
         # Issue 15944: Allow all source formats when casting to bytes.
-        ctypes = test.support.import_module("ctypes")
+        ctypes = import_helper.import_module("ctypes")
         p6 = bytes(ctypes.c_double(0.6))
 
         d = ctypes.c_double()
diff --git a/Lib/test/test_os.py b/Lib/test/test_os.py
index ef2395d..0315207 100644
--- a/Lib/test/test_os.py
+++ b/Lib/test/test_os.py
@@ -30,8 +30,10 @@ import unittest
 import uuid
 import warnings
 from test import support
+from test.support import os_helper
 from test.support import socket_helper
 from test.support import threading_helper
+from test.support import warnings_helper
 from platform import win32_is_iot
 
 try:
@@ -57,7 +59,8 @@ except ImportError:
     INT_MAX = PY_SSIZE_T_MAX = sys.maxsize
 
 from test.support.script_helper import assert_python_ok
-from test.support import unix_shell, FakePath
+from test.support import unix_shell
+from test.support.os_helper import FakePath
 
 
 root_in_posix = False
@@ -109,7 +112,7 @@ class MiscTests(unittest.TestCase):
         dirname = dirname + ('a' * (dirlen - len(dirname)))
 
         with tempfile.TemporaryDirectory() as tmpdir:
-            with support.change_cwd(tmpdir) as path:
+            with os_helper.change_cwd(tmpdir) as path:
                 expected = path
 
                 while True:
@@ -153,17 +156,17 @@ class MiscTests(unittest.TestCase):
 # Tests creating TESTFN
 class FileTests(unittest.TestCase):
     def setUp(self):
-        if os.path.lexists(support.TESTFN):
-            os.unlink(support.TESTFN)
+        if os.path.lexists(os_helper.TESTFN):
+            os.unlink(os_helper.TESTFN)
     tearDown = setUp
 
     def test_access(self):
-        f = os.open(support.TESTFN, os.O_CREAT|os.O_RDWR)
+        f = os.open(os_helper.TESTFN, os.O_CREAT|os.O_RDWR)
         os.close(f)
-        self.assertTrue(os.access(support.TESTFN, os.W_OK))
+        self.assertTrue(os.access(os_helper.TESTFN, os.W_OK))
 
     def test_closerange(self):
-        first = os.open(support.TESTFN, os.O_CREAT|os.O_RDWR)
+        first = os.open(os_helper.TESTFN, os.O_CREAT|os.O_RDWR)
         # We must allocate two consecutive file descriptors, otherwise
         # it will mess up other file descriptors (perhaps even the three
         # standard ones).
@@ -185,14 +188,14 @@ class FileTests(unittest.TestCase):
 
     @support.cpython_only
     def test_rename(self):
-        path = support.TESTFN
+        path = os_helper.TESTFN
         old = sys.getrefcount(path)
         self.assertRaises(TypeError, os.rename, path, 0)
         new = sys.getrefcount(path)
         self.assertEqual(old, new)
 
     def test_read(self):
-        with open(support.TESTFN, "w+b") as fobj:
+        with open(os_helper.TESTFN, "w+b") as fobj:
             fobj.write(b"spam")
             fobj.flush()
             fd = fobj.fileno()
@@ -208,12 +211,12 @@ class FileTests(unittest.TestCase):
                          "needs INT_MAX < PY_SSIZE_T_MAX")
     @support.bigmemtest(size=INT_MAX + 10, memuse=1, dry_run=False)
     def test_large_read(self, size):
-        self.addCleanup(support.unlink, support.TESTFN)
-        create_file(support.TESTFN, b'test')
+        self.addCleanup(os_helper.unlink, os_helper.TESTFN)
+        create_file(os_helper.TESTFN, b'test')
 
         # Issue #21932: Make sure that os.read() does not raise an
         # OverflowError for size larger than INT_MAX
-        with open(support.TESTFN, "rb") as fp:
+        with open(os_helper.TESTFN, "rb") as fp:
             data = os.read(fp.fileno(), size)
 
         # The test does not try to read more than 2 GiB at once because the
@@ -222,13 +225,13 @@ class FileTests(unittest.TestCase):
 
     def test_write(self):
         # os.write() accepts bytes- and buffer-like objects but not strings
-        fd = os.open(support.TESTFN, os.O_CREAT | os.O_WRONLY)
+        fd = os.open(os_helper.TESTFN, os.O_CREAT | os.O_WRONLY)
         self.assertRaises(TypeError, os.write, fd, "beans")
         os.write(fd, b"bacon\n")
         os.write(fd, bytearray(b"eggs\n"))
         os.write(fd, memoryview(b"spam\n"))
         os.close(fd)
-        with open(support.TESTFN, "rb") as fobj:
+        with open(os_helper.TESTFN, "rb") as fobj:
             self.assertEqual(fobj.read().splitlines(),
                 [b"bacon", b"eggs", b"spam"])
 
@@ -252,12 +255,12 @@ class FileTests(unittest.TestCase):
         self.write_windows_console(sys.executable, "-u", "-c", code)
 
     def fdopen_helper(self, *args):
-        fd = os.open(support.TESTFN, os.O_RDONLY)
+        fd = os.open(os_helper.TESTFN, os.O_RDONLY)
         f = os.fdopen(fd, *args)
         f.close()
 
     def test_fdopen(self):
-        fd = os.open(support.TESTFN, os.O_CREAT|os.O_RDWR)
+        fd = os.open(os_helper.TESTFN, os.O_CREAT|os.O_RDWR)
         os.close(fd)
 
         self.fdopen_helper()
@@ -265,15 +268,15 @@ class FileTests(unittest.TestCase):
         self.fdopen_helper('r', 100)
 
     def test_replace(self):
-        TESTFN2 = support.TESTFN + ".2"
-        self.addCleanup(support.unlink, support.TESTFN)
-        self.addCleanup(support.unlink, TESTFN2)
+        TESTFN2 = os_helper.TESTFN + ".2"
+        self.addCleanup(os_helper.unlink, os_helper.TESTFN)
+        self.addCleanup(os_helper.unlink, TESTFN2)
 
-        create_file(support.TESTFN, b"1")
+        create_file(os_helper.TESTFN, b"1")
         create_file(TESTFN2, b"2")
 
-        os.replace(support.TESTFN, TESTFN2)
-        self.assertRaises(FileNotFoundError, os.stat, support.TESTFN)
+        os.replace(os_helper.TESTFN, TESTFN2)
+        self.assertRaises(FileNotFoundError, os.stat, os_helper.TESTFN)
         with open(TESTFN2, 'r') as f:
             self.assertEqual(f.read(), "1")
 
@@ -285,7 +288,7 @@ class FileTests(unittest.TestCase):
     def test_symlink_keywords(self):
         symlink = support.get_attribute(os, "symlink")
         try:
-            symlink(src='target', dst=support.TESTFN,
+            symlink(src='target', dst=os_helper.TESTFN,
                 target_is_directory=False, dir_fd=None)
         except (NotImplementedError, OSError):
             pass  # No OS support or unprivileged user
@@ -297,18 +300,18 @@ class FileTests(unittest.TestCase):
 
     @unittest.skipUnless(hasattr(os, 'copy_file_range'), 'test needs os.copy_file_range()')
     def test_copy_file_range(self):
-        TESTFN2 = support.TESTFN + ".3"
+        TESTFN2 = os_helper.TESTFN + ".3"
         data = b'0123456789'
 
-        create_file(support.TESTFN, data)
-        self.addCleanup(support.unlink, support.TESTFN)
+        create_file(os_helper.TESTFN, data)
+        self.addCleanup(os_helper.unlink, os_helper.TESTFN)
 
-        in_file = open(support.TESTFN, 'rb')
+        in_file = open(os_helper.TESTFN, 'rb')
         self.addCleanup(in_file.close)
         in_fd = in_file.fileno()
 
         out_file = open(TESTFN2, 'w+b')
-        self.addCleanup(support.unlink, TESTFN2)
+        self.addCleanup(os_helper.unlink, TESTFN2)
         self.addCleanup(out_file.close)
         out_fd = out_file.fileno()
 
@@ -331,21 +334,21 @@ class FileTests(unittest.TestCase):
 
     @unittest.skipUnless(hasattr(os, 'copy_file_range'), 'test needs os.copy_file_range()')
     def test_copy_file_range_offset(self):
-        TESTFN4 = support.TESTFN + ".4"
+        TESTFN4 = os_helper.TESTFN + ".4"
         data = b'0123456789'
         bytes_to_copy = 6
         in_skip = 3
         out_seek = 5
 
-        create_file(support.TESTFN, data)
-        self.addCleanup(support.unlink, support.TESTFN)
+        create_file(os_helper.TESTFN, data)
+        self.addCleanup(os_helper.unlink, os_helper.TESTFN)
 
-        in_file = open(support.TESTFN, 'rb')
+        in_file = open(os_helper.TESTFN, 'rb')
         self.addCleanup(in_file.close)
         in_fd = in_file.fileno()
 
         out_file = open(TESTFN4, 'w+b')
-        self.addCleanup(support.unlink, TESTFN4)
+        self.addCleanup(os_helper.unlink, TESTFN4)
         self.addCleanup(out_file.close)
         out_fd = out_file.fileno()
 
@@ -377,8 +380,8 @@ class FileTests(unittest.TestCase):
 # Test attributes on return values from os.*stat* family.
 class StatAttributeTests(unittest.TestCase):
     def setUp(self):
-        self.fname = support.TESTFN
-        self.addCleanup(support.unlink, self.fname)
+        self.fname = os_helper.TESTFN
+        self.addCleanup(os_helper.unlink, self.fname)
         create_file(self.fname, b"ABC")
 
     def check_stat_attributes(self, fname):
@@ -563,7 +566,7 @@ class StatAttributeTests(unittest.TestCase):
             0)
 
         # test directory st_file_attributes (FILE_ATTRIBUTE_DIRECTORY set)
-        dirname = support.TESTFN + "dir"
+        dirname = os_helper.TESTFN + "dir"
         os.mkdir(dirname)
         self.addCleanup(os.rmdir, dirname)
 
@@ -580,7 +583,7 @@ class StatAttributeTests(unittest.TestCase):
         # os.environ['TEMP'] should be located on a volume that
         # supports file ACLs.
         fname = os.path.join(os.environ['TEMP'], self.fname)
-        self.addCleanup(support.unlink, fname)
+        self.addCleanup(os_helper.unlink, fname)
         create_file(fname, b'ABC')
         # Deny the right to [S]YNCHRONIZE on the file to
         # force CreateFile to fail with ERROR_ACCESS_DENIED.
@@ -605,10 +608,10 @@ class StatAttributeTests(unittest.TestCase):
 
 class UtimeTests(unittest.TestCase):
     def setUp(self):
-        self.dirname = support.TESTFN
+        self.dirname = os_helper.TESTFN
         self.fname = os.path.join(self.dirname, "f1")
 
-        self.addCleanup(support.rmtree, self.dirname)
+        self.addCleanup(os_helper.rmtree, self.dirname)
         os.mkdir(self.dirname)
         create_file(self.fname)
 
@@ -961,7 +964,7 @@ class EnvironTests(mapping_tests.BasicTestMappingProtocol):
         value = "testvalue"
         code = f'import os; print(repr(os.environ.get({name!r})))'
 
-        with support.EnvironmentVarGuard() as env:
+        with os_helper.EnvironmentVarGuard() as env:
             env.pop(name, None)
 
             os.putenv(name, value)
@@ -1132,7 +1135,7 @@ class WalkTests(unittest.TestCase):
 
     def setUp(self):
         join = os.path.join
-        self.addCleanup(support.rmtree, support.TESTFN)
+        self.addCleanup(os_helper.rmtree, os_helper.TESTFN)
 
         # Build:
         #     TESTFN/
@@ -1151,7 +1154,7 @@ class WalkTests(unittest.TestCase):
         #           broken_link3
         #       TEST2/
         #         tmp4              a lone file
-        self.walk_path = join(support.TESTFN, "TEST1")
+        self.walk_path = join(os_helper.TESTFN, "TEST1")
         self.sub1_path = join(self.walk_path, "SUB1")
         self.sub11_path = join(self.sub1_path, "SUB11")
         sub2_path = join(self.walk_path, "SUB2")
@@ -1161,8 +1164,8 @@ class WalkTests(unittest.TestCase):
         tmp3_path = join(sub2_path, "tmp3")
         tmp5_path = join(sub21_path, "tmp3")
         self.link_path = join(sub2_path, "link")
-        t2_path = join(support.TESTFN, "TEST2")
-        tmp4_path = join(support.TESTFN, "TEST2", "tmp4")
+        t2_path = join(os_helper.TESTFN, "TEST2")
+        tmp4_path = join(os_helper.TESTFN, "TEST2", "tmp4")
         broken_link_path = join(sub2_path, "broken_link")
         broken_link2_path = join(sub2_path, "broken_link2")
         broken_link3_path = join(sub2_path, "broken_link3")
@@ -1177,7 +1180,7 @@ class WalkTests(unittest.TestCase):
             with open(path, "x", encoding='utf-8') as f:
                 f.write("I'm " + path + " and proud of it.  Blame test_os.\n")
 
-        if support.can_symlink():
+        if os_helper.can_symlink():
             os.symlink(os.path.abspath(t2_path), self.link_path)
             os.symlink('broken', broken_link_path, True)
             os.symlink(join('tmp3', 'broken'), broken_link2_path, True)
@@ -1260,7 +1263,7 @@ class WalkTests(unittest.TestCase):
                          self.sub2_tree)
 
     def test_walk_symlink(self):
-        if not support.can_symlink():
+        if not os_helper.can_symlink():
             self.skipTest("need symlink support")
 
         # Walk, following symlinks.
@@ -1296,7 +1299,7 @@ class WalkTests(unittest.TestCase):
 
     def test_walk_many_open_files(self):
         depth = 30
-        base = os.path.join(support.TESTFN, 'deep')
+        base = os.path.join(os_helper.TESTFN, 'deep')
         p = os.path.join(base, *(['d']*depth))
         os.makedirs(p)
 
@@ -1346,13 +1349,13 @@ class FwalkTests(WalkTests):
                 self.assertEqual(expected[root], (set(dirs), set(files)))
 
     def test_compare_to_walk(self):
-        kwargs = {'top': support.TESTFN}
+        kwargs = {'top': os_helper.TESTFN}
         self._compare_to_walk(kwargs, kwargs)
 
     def test_dir_fd(self):
         try:
             fd = os.open(".", os.O_RDONLY)
-            walk_kwargs = {'top': support.TESTFN}
+            walk_kwargs = {'top': os_helper.TESTFN}
             fwalk_kwargs = walk_kwargs.copy()
             fwalk_kwargs['dir_fd'] = fd
             self._compare_to_walk(walk_kwargs, fwalk_kwargs)
@@ -1362,7 +1365,7 @@ class FwalkTests(WalkTests):
     def test_yields_correct_dir_fd(self):
         # check returned file descriptors
         for topdown, follow_symlinks in itertools.product((True, False), repeat=2):
-            args = support.TESTFN, topdown, None
+            args = os_helper.TESTFN, topdown, None
             for root, dirs, files, rootfd in self.fwalk(*args, follow_symlinks=follow_symlinks):
                 # check that the FD is valid
                 os.fstat(rootfd)
@@ -1378,7 +1381,7 @@ class FwalkTests(WalkTests):
         minfd = os.dup(1)
         os.close(minfd)
         for i in range(256):
-            for x in self.fwalk(support.TESTFN):
+            for x in self.fwalk(os_helper.TESTFN):
                 pass
         newfd = os.dup(1)
         self.addCleanup(os.close, newfd)
@@ -1416,10 +1419,10 @@ class BytesFwalkTests(FwalkTests):
 
 class MakedirTests(unittest.TestCase):
     def setUp(self):
-        os.mkdir(support.TESTFN)
+        os.mkdir(os_helper.TESTFN)
 
     def test_makedir(self):
-        base = support.TESTFN
+        base = os_helper.TESTFN
         path = os.path.join(base, 'dir1', 'dir2', 'dir3')
         os.makedirs(path)             # Should work
         path = os.path.join(base, 'dir1', 'dir2', 'dir3', 'dir4')
@@ -1434,8 +1437,8 @@ class MakedirTests(unittest.TestCase):
         os.makedirs(path)
 
     def test_mode(self):
-        with support.temp_umask(0o002):
-            base = support.TESTFN
+        with os_helper.temp_umask(0o002):
+            base = os_helper.TESTFN
             parent = os.path.join(base, 'dir1')
             path = os.path.join(parent, 'dir2')
             os.makedirs(path, 0o555)
@@ -1446,7 +1449,7 @@ class MakedirTests(unittest.TestCase):
                 self.assertEqual(os.stat(parent).st_mode & 0o777, 0o775)
 
     def test_exist_ok_existing_directory(self):
-        path = os.path.join(support.TESTFN, 'dir1')
+        path = os.path.join(os_helper.TESTFN, 'dir1')
         mode = 0o777
         old_mask = os.umask(0o022)
         os.makedirs(path, mode)
@@ -1460,18 +1463,18 @@ class MakedirTests(unittest.TestCase):
         os.makedirs(os.path.abspath('/'), exist_ok=True)
 
     def test_exist_ok_s_isgid_directory(self):
-        path = os.path.join(support.TESTFN, 'dir1')
+        path = os.path.join(os_helper.TESTFN, 'dir1')
         S_ISGID = stat.S_ISGID
         mode = 0o777
         old_mask = os.umask(0o022)
         try:
             existing_testfn_mode = stat.S_IMODE(
-                    os.lstat(support.TESTFN).st_mode)
+                    os.lstat(os_helper.TESTFN).st_mode)
             try:
-                os.chmod(support.TESTFN, existing_testfn_mode | S_ISGID)
+                os.chmod(os_helper.TESTFN, existing_testfn_mode | S_ISGID)
             except PermissionError:
                 raise unittest.SkipTest('Cannot set S_ISGID for dir.')
-            if (os.lstat(support.TESTFN).st_mode & S_ISGID != S_ISGID):
+            if (os.lstat(os_helper.TESTFN).st_mode & S_ISGID != S_ISGID):
                 raise unittest.SkipTest('No support for S_ISGID dir mode.')
             # The os should apply S_ISGID from the parent dir for us, but
             # this test need not depend on that behavior.  Be explicit.
@@ -1487,8 +1490,8 @@ class MakedirTests(unittest.TestCase):
             os.umask(old_mask)
 
     def test_exist_ok_existing_regular_file(self):
-        base = support.TESTFN
-        path = os.path.join(support.TESTFN, 'dir1')
+        base = os_helper.TESTFN
+        path = os.path.join(os_helper.TESTFN, 'dir1')
         with open(path, 'w') as f:
             f.write('abc')
         self.assertRaises(OSError, os.makedirs, path)
@@ -1497,12 +1500,12 @@ class MakedirTests(unittest.TestCase):
         os.remove(path)
 
     def tearDown(self):
-        path = os.path.join(support.TESTFN, 'dir1', 'dir2', 'dir3',
+        path = os.path.join(os_helper.TESTFN, 'dir1', 'dir2', 'dir3',
                             'dir4', 'dir5', 'dir6')
         # If the tests failed, the bottom-most directory ('../dir6')
         # may not have been created, so we look for the outermost directory
         # that exists.
-        while not os.path.exists(path) and path != support.TESTFN:
+        while not os.path.exists(path) and path != os_helper.TESTFN:
             path = os.path.dirname(path)
 
         os.removedirs(path)
@@ -1513,17 +1516,17 @@ class ChownFileTests(unittest.TestCase):
 
     @classmethod
     def setUpClass(cls):
-        os.mkdir(support.TESTFN)
+        os.mkdir(os_helper.TESTFN)
 
     def test_chown_uid_gid_arguments_must_be_index(self):
-        stat = os.stat(support.TESTFN)
+        stat = os.stat(os_helper.TESTFN)
         uid = stat.st_uid
         gid = stat.st_gid
         for value in (-1.0, -1j, decimal.Decimal(-1), fractions.Fraction(-2, 2)):
-            self.assertRaises(TypeError, os.chown, support.TESTFN, value, gid)
-            self.assertRaises(TypeError, os.chown, support.TESTFN, uid, value)
-        self.assertIsNone(os.chown(support.TESTFN, uid, gid))
-        self.assertIsNone(os.chown(support.TESTFN, -1, -1))
+            self.assertRaises(TypeError, os.chown, os_helper.TESTFN, value, gid)
+            self.assertRaises(TypeError, os.chown, os_helper.TESTFN, uid, value)
+        self.assertIsNone(os.chown(os_helper.TESTFN, uid, gid))
+        self.assertIsNone(os.chown(os_helper.TESTFN, -1, -1))
 
     @unittest.skipUnless(hasattr(os, 'getgroups'), 'need os.getgroups')
     def test_chown_gid(self):
@@ -1532,61 +1535,61 @@ class ChownFileTests(unittest.TestCase):
             self.skipTest("test needs at least 2 groups")
 
         gid_1, gid_2 = groups[:2]
-        uid = os.stat(support.TESTFN).st_uid
+        uid = os.stat(os_helper.TESTFN).st_uid
 
-        os.chown(support.TESTFN, uid, gid_1)
-        gid = os.stat(support.TESTFN).st_gid
+        os.chown(os_helper.TESTFN, uid, gid_1)
+        gid = os.stat(os_helper.TESTFN).st_gid
         self.assertEqual(gid, gid_1)
 
-        os.chown(support.TESTFN, uid, gid_2)
-        gid = os.stat(support.TESTFN).st_gid
+        os.chown(os_helper.TESTFN, uid, gid_2)
+        gid = os.stat(os_helper.TESTFN).st_gid
         self.assertEqual(gid, gid_2)
 
     @unittest.skipUnless(root_in_posix and len(all_users) > 1,
                          "test needs root privilege and more than one user")
     def test_chown_with_root(self):
         uid_1, uid_2 = all_users[:2]
-        gid = os.stat(support.TESTFN).st_gid
-        os.chown(support.TESTFN, uid_1, gid)
-        uid = os.stat(support.TESTFN).st_uid
+        gid = os.stat(os_helper.TESTFN).st_gid
+        os.chown(os_helper.TESTFN, uid_1, gid)
+        uid = os.stat(os_helper.TESTFN).st_uid
         self.assertEqual(uid, uid_1)
-        os.chown(support.TESTFN, uid_2, gid)
-        uid = os.stat(support.TESTFN).st_uid
+        os.chown(os_helper.TESTFN, uid_2, gid)
+        uid = os.stat(os_helper.TESTFN).st_uid
         self.assertEqual(uid, uid_2)
 
     @unittest.skipUnless(not root_in_posix and len(all_users) > 1,
                          "test needs non-root account and more than one user")
     def test_chown_without_permission(self):
         uid_1, uid_2 = all_users[:2]
-        gid = os.stat(support.TESTFN).st_gid
+        gid = os.stat(os_helper.TESTFN).st_gid
         with self.assertRaises(PermissionError):
-            os.chown(support.TESTFN, uid_1, gid)
-            os.chown(support.TESTFN, uid_2, gid)
+            os.chown(os_helper.TESTFN, uid_1, gid)
+            os.chown(os_helper.TESTFN, uid_2, gid)
 
     @classmethod
     def tearDownClass(cls):
-        os.rmdir(support.TESTFN)
+        os.rmdir(os_helper.TESTFN)
 
 
 class RemoveDirsTests(unittest.TestCase):
     def setUp(self):
-        os.makedirs(support.TESTFN)
+        os.makedirs(os_helper.TESTFN)
 
     def tearDown(self):
-        support.rmtree(support.TESTFN)
+        os_helper.rmtree(os_helper.TESTFN)
 
     def test_remove_all(self):
-        dira = os.path.join(support.TESTFN, 'dira')
+        dira = os.path.join(os_helper.TESTFN, 'dira')
         os.mkdir(dira)
         dirb = os.path.join(dira, 'dirb')
         os.mkdir(dirb)
         os.removedirs(dirb)
         self.assertFalse(os.path.exists(dirb))
         self.assertFalse(os.path.exists(dira))
-        self.assertFalse(os.path.exists(support.TESTFN))
+        self.assertFalse(os.path.exists(os_helper.TESTFN))
 
     def test_remove_partial(self):
-        dira = os.path.join(support.TESTFN, 'dira')
+        dira = os.path.join(os_helper.TESTFN, 'dira')
         os.mkdir(dira)
         dirb = os.path.join(dira, 'dirb')
         os.mkdir(dirb)
@@ -1594,10 +1597,10 @@ class RemoveDirsTests(unittest.TestCase):
         os.removedirs(dirb)
         self.assertFalse(os.path.exists(dirb))
         self.assertTrue(os.path.exists(dira))
-        self.assertTrue(os.path.exists(support.TESTFN))
+        self.assertTrue(os.path.exists(os_helper.TESTFN))
 
     def test_remove_nothing(self):
-        dira = os.path.join(support.TESTFN, 'dira')
+        dira = os.path.join(os_helper.TESTFN, 'dira')
         os.mkdir(dira)
         dirb = os.path.join(dira, 'dirb')
         os.mkdir(dirb)
@@ -1606,7 +1609,7 @@ class RemoveDirsTests(unittest.TestCase):
             os.removedirs(dirb)
         self.assertTrue(os.path.exists(dirb))
         self.assertTrue(os.path.exists(dira))
-        self.assertTrue(os.path.exists(support.TESTFN))
+        self.assertTrue(os.path.exists(os_helper.TESTFN))
 
 
 class DevNullTests(unittest.TestCase):
@@ -1744,8 +1747,8 @@ class URandomFDTests(unittest.TestCase):
     def test_urandom_fd_reopened(self):
         # Issue #21207: urandom() should detect its fd to /dev/urandom
         # changed to something else, and reopen it.
-        self.addCleanup(support.unlink, support.TESTFN)
-        create_file(support.TESTFN, b"x" * 256)
+        self.addCleanup(os_helper.unlink, os_helper.TESTFN)
+        create_file(os_helper.TESTFN, b"x" * 256)
 
         code = """if 1:
             import os
@@ -1771,7 +1774,7 @@ class URandomFDTests(unittest.TestCase):
                     os.dup2(new_fd, fd)
                 sys.stdout.buffer.write(os.urandom(4))
                 sys.stdout.buffer.write(os.urandom(4))
-            """.format(TESTFN=support.TESTFN)
+            """.format(TESTFN=os_helper.TESTFN)
         rc, out, err = assert_python_ok('-Sc', code)
         self.assertEqual(len(out), 8)
         self.assertNotEqual(out[0:4], out[4:8])
@@ -1923,36 +1926,36 @@ class ExecTests(unittest.TestCase):
 class Win32ErrorTests(unittest.TestCase):
     def setUp(self):
         try:
-            os.stat(support.TESTFN)
+            os.stat(os_helper.TESTFN)
         except FileNotFoundError:
             exists = False
         except OSError as exc:
             exists = True
             self.fail("file %s must not exist; os.stat failed with %s"
-                      % (support.TESTFN, exc))
+                      % (os_helper.TESTFN, exc))
         else:
-            self.fail("file %s must not exist" % support.TESTFN)
+            self.fail("file %s must not exist" % os_helper.TESTFN)
 
     def test_rename(self):
-        self.assertRaises(OSError, os.rename, support.TESTFN, support.TESTFN+".bak")
+        self.assertRaises(OSError, os.rename, os_helper.TESTFN, os_helper.TESTFN+".bak")
 
     def test_remove(self):
-        self.assertRaises(OSError, os.remove, support.TESTFN)
+        self.assertRaises(OSError, os.remove, os_helper.TESTFN)
 
     def test_chdir(self):
-        self.assertRaises(OSError, os.chdir, support.TESTFN)
+        self.assertRaises(OSError, os.chdir, os_helper.TESTFN)
 
     def test_mkdir(self):
-        self.addCleanup(support.unlink, support.TESTFN)
+        self.addCleanup(os_helper.unlink, os_helper.TESTFN)
 
-        with open(support.TESTFN, "x") as f:
-            self.assertRaises(OSError, os.mkdir, support.TESTFN)
+        with open(os_helper.TESTFN, "x") as f:
+            self.assertRaises(OSError, os.mkdir, os_helper.TESTFN)
 
     def test_utime(self):
-        self.assertRaises(OSError, os.utime, support.TESTFN, None)
+        self.assertRaises(OSError, os.utime, os_helper.TESTFN, None)
 
     def test_chmod(self):
-        self.assertRaises(OSError, os.chmod, support.TESTFN, 0)
+        self.assertRaises(OSError, os.chmod, os_helper.TESTFN, 0)
 
 
 class TestInvalidFD(unittest.TestCase):
@@ -1970,7 +1973,7 @@ class TestInvalidFD(unittest.TestCase):
 
     def check(self, f, *args):
         try:
-            f(support.make_bad_fd(), *args)
+            f(os_helper.make_bad_fd(), *args)
         except OSError as e:
             self.assertEqual(e.errno, errno.EBADF)
         else:
@@ -1979,11 +1982,11 @@ class TestInvalidFD(unittest.TestCase):
 
     @unittest.skipUnless(hasattr(os, 'isatty'), 'test needs os.isatty()')
     def test_isatty(self):
-        self.assertEqual(os.isatty(support.make_bad_fd()), False)
+        self.assertEqual(os.isatty(os_helper.make_bad_fd()), False)
 
     @unittest.skipUnless(hasattr(os, 'closerange'), 'test needs os.closerange()')
     def test_closerange(self):
-        fd = support.make_bad_fd()
+        fd = os_helper.make_bad_fd()
         # Make sure none of the descriptors we are about to close are
         # currently valid (issue 6542).
         for i in range(10):
@@ -2057,8 +2060,8 @@ class TestInvalidFD(unittest.TestCase):
 
 class LinkTests(unittest.TestCase):
     def setUp(self):
-        self.file1 = support.TESTFN
-        self.file2 = os.path.join(support.TESTFN + "2")
+        self.file1 = os_helper.TESTFN
+        self.file2 = os.path.join(os_helper.TESTFN + "2")
 
     def tearDown(self):
         for file in (self.file1, self.file2):
@@ -2163,12 +2166,12 @@ class PosixUidGidTests(unittest.TestCase):
 @unittest.skipIf(sys.platform == "win32", "Posix specific tests")
 class Pep383Tests(unittest.TestCase):
     def setUp(self):
-        if support.TESTFN_UNENCODABLE:
-            self.dir = support.TESTFN_UNENCODABLE
-        elif support.TESTFN_NONASCII:
-            self.dir = support.TESTFN_NONASCII
+        if os_helper.TESTFN_UNENCODABLE:
+            self.dir = os_helper.TESTFN_UNENCODABLE
+        elif os_helper.TESTFN_NONASCII:
+            self.dir = os_helper.TESTFN_NONASCII
         else:
-            self.dir = support.TESTFN
+            self.dir = os_helper.TESTFN
         self.bdir = os.fsencode(self.dir)
 
         bytesfn = []
@@ -2178,11 +2181,11 @@ class Pep383Tests(unittest.TestCase):
             except UnicodeEncodeError:
                 return
             bytesfn.append(fn)
-        add_filename(support.TESTFN_UNICODE)
-        if support.TESTFN_UNENCODABLE:
-            add_filename(support.TESTFN_UNENCODABLE)
-        if support.TESTFN_NONASCII:
-            add_filename(support.TESTFN_NONASCII)
+        add_filename(os_helper.TESTFN_UNICODE)
+        if os_helper.TESTFN_UNENCODABLE:
+            add_filename(os_helper.TESTFN_UNENCODABLE)
+        if os_helper.TESTFN_NONASCII:
+            add_filename(os_helper.TESTFN_NONASCII)
         if not bytesfn:
             self.skipTest("couldn't create any non-ascii filename")
 
@@ -2190,7 +2193,7 @@ class Pep383Tests(unittest.TestCase):
         os.mkdir(self.dir)
         try:
             for fn in bytesfn:
-                support.create_empty_file(os.path.join(self.bdir, fn))
+                os_helper.create_empty_file(os.path.join(self.bdir, fn))
                 fn = os.fsdecode(fn)
                 if fn in self.unicodefn:
                     raise ValueError("duplicate filename")
@@ -2356,9 +2359,9 @@ class Win32ListdirTests(unittest.TestCase):
         self.created_paths = []
         for i in range(2):
             dir_name = 'SUB%d' % i
-            dir_path = os.path.join(support.TESTFN, dir_name)
+            dir_path = os.path.join(os_helper.TESTFN, dir_name)
             file_name = 'FILE%d' % i
-            file_path = os.path.join(support.TESTFN, file_name)
+            file_path = os.path.join(os_helper.TESTFN, file_name)
             os.makedirs(dir_path)
             with open(file_path, 'w', encoding='utf-8') as f:
                 f.write("I'm %s and proud of it. Blame test_os.\n" % file_path)
@@ -2366,31 +2369,31 @@ class Win32ListdirTests(unittest.TestCase):
         self.created_paths.sort()
 
     def tearDown(self):
-        shutil.rmtree(support.TESTFN)
+        shutil.rmtree(os_helper.TESTFN)
 
     def test_listdir_no_extended_path(self):
         """Test when the path is not an "extended" path."""
         # unicode
         self.assertEqual(
-                sorted(os.listdir(support.TESTFN)),
+                sorted(os.listdir(os_helper.TESTFN)),
                 self.created_paths)
 
         # bytes
         self.assertEqual(
-                sorted(os.listdir(os.fsencode(support.TESTFN))),
+                sorted(os.listdir(os.fsencode(os_helper.TESTFN))),
                 [os.fsencode(path) for path in self.created_paths])
 
     def test_listdir_extended_path(self):
         """Test when the path starts with '\\\\?\\'."""
         # See: http://msdn.microsoft.com/en-us/library/windows/desktop/aa365247(v=vs.85).aspx#maxpath
         # unicode
-        path = '\\\\?\\' + os.path.abspath(support.TESTFN)
+        path = '\\\\?\\' + os.path.abspath(os_helper.TESTFN)
         self.assertEqual(
                 sorted(os.listdir(path)),
                 self.created_paths)
 
         # bytes
-        path = b'\\\\?\\' + os.fsencode(os.path.abspath(support.TESTFN))
+        path = b'\\\\?\\' + os.fsencode(os.path.abspath(os_helper.TESTFN))
         self.assertEqual(
                 sorted(os.listdir(path)),
                 [os.fsencode(path) for path in self.created_paths])
@@ -2433,32 +2436,32 @@ class ReadlinkTests(unittest.TestCase):
         self.assertRaises(FileNotFoundError, os.readlink,
                           FakePath('missing-link'))
 
-    @support.skip_unless_symlink
+    @os_helper.skip_unless_symlink
     def test_pathlike(self):
         os.symlink(self.filelink_target, self.filelink)
-        self.addCleanup(support.unlink, self.filelink)
+        self.addCleanup(os_helper.unlink, self.filelink)
         filelink = FakePath(self.filelink)
         self.assertPathEqual(os.readlink(filelink), self.filelink_target)
 
-    @support.skip_unless_symlink
+    @os_helper.skip_unless_symlink
     def test_pathlike_bytes(self):
         os.symlink(self.filelinkb_target, self.filelinkb)
-        self.addCleanup(support.unlink, self.filelinkb)
+        self.addCleanup(os_helper.unlink, self.filelinkb)
         path = os.readlink(FakePath(self.filelinkb))
         self.assertPathEqual(path, self.filelinkb_target)
         self.assertIsInstance(path, bytes)
 
-    @support.skip_unless_symlink
+    @os_helper.skip_unless_symlink
     def test_bytes(self):
         os.symlink(self.filelinkb_target, self.filelinkb)
-        self.addCleanup(support.unlink, self.filelinkb)
+        self.addCleanup(os_helper.unlink, self.filelinkb)
         path = os.readlink(self.filelinkb)
         self.assertPathEqual(path, self.filelinkb_target)
         self.assertIsInstance(path, bytes)
 
 
 @unittest.skipUnless(sys.platform == "win32", "Win32 specific tests")
-@support.skip_unless_symlink
+@os_helper.skip_unless_symlink
 class Win32SymlinkTests(unittest.TestCase):
     filelink = 'filelinktest'
     filelink_target = os.path.abspath(__file__)
@@ -2529,10 +2532,10 @@ class Win32SymlinkTests(unittest.TestCase):
         self.assertNotEqual(os.lstat(bytes_link), os.stat(bytes_link))
 
     def test_12084(self):
-        level1 = os.path.abspath(support.TESTFN)
+        level1 = os.path.abspath(os_helper.TESTFN)
         level2 = os.path.join(level1, "level2")
         level3 = os.path.join(level2, "level3")
-        self.addCleanup(support.rmtree, level1)
+        self.addCleanup(os_helper.rmtree, level1)
 
         os.mkdir(level1)
         os.mkdir(level2)
@@ -2718,7 +2721,7 @@ class Win32NtTests(unittest.TestCase):
 
         self.assertEqual(0, handle_delta)
 
-@support.skip_unless_symlink
+@os_helper.skip_unless_symlink
 class NonLocalSymlinkTests(unittest.TestCase):
 
     def setUp(self):
@@ -2857,8 +2860,8 @@ class SpawnTests(unittest.TestCase):
     def create_args(self, *, with_env=False, use_bytes=False):
         self.exitcode = 17
 
-        filename = support.TESTFN
-        self.addCleanup(support.unlink, filename)
+        filename = os_helper.TESTFN
+        self.addCleanup(os_helper.unlink, filename)
 
         if not with_env:
             code = 'import sys; sys.exit(%s)' % self.exitcode
@@ -3009,8 +3012,8 @@ class SpawnTests(unittest.TestCase):
             self.assertEqual(exitcode, 127)
 
         # equal character in the environment variable value
-        filename = support.TESTFN
-        self.addCleanup(support.unlink, filename)
+        filename = os_helper.TESTFN
+        self.addCleanup(os_helper.unlink, filename)
         with open(filename, "w") as fp:
             fp.write('import sys, os\n'
                      'if os.getenv("FRUIT") != "orange=lemon":\n'
@@ -3165,12 +3168,12 @@ class TestSendfile(unittest.TestCase):
     @classmethod
     def setUpClass(cls):
         cls.key = threading_helper.threading_setup()
-        create_file(support.TESTFN, cls.DATA)
+        create_file(os_helper.TESTFN, cls.DATA)
 
     @classmethod
     def tearDownClass(cls):
         threading_helper.threading_cleanup(*cls.key)
-        support.unlink(support.TESTFN)
+        os_helper.unlink(os_helper.TESTFN)
 
     def setUp(self):
         self.server = SendfileTestServer((socket_helper.HOST, 0))
@@ -3181,7 +3184,7 @@ class TestSendfile(unittest.TestCase):
         # synchronize by waiting for "220 ready" response
         self.client.recv(1024)
         self.sockno = self.client.fileno()
-        self.file = open(support.TESTFN, 'rb')
+        self.file = open(os_helper.TESTFN, 'rb')
         self.fileno = self.file.fileno()
 
     def tearDown(self):
@@ -3313,10 +3316,10 @@ class TestSendfile(unittest.TestCase):
 
     @requires_headers_trailers
     def test_trailers(self):
-        TESTFN2 = support.TESTFN + "2"
+        TESTFN2 = os_helper.TESTFN + "2"
         file_data = b"abcdef"
 
-        self.addCleanup(support.unlink, TESTFN2)
+        self.addCleanup(os_helper.unlink, TESTFN2)
         create_file(TESTFN2, file_data)
 
         with open(TESTFN2, 'rb') as f:
@@ -3362,13 +3365,13 @@ def supports_extended_attributes():
         return False
 
     try:
-        with open(support.TESTFN, "xb", 0) as fp:
+        with open(os_helper.TESTFN, "xb", 0) as fp:
             try:
                 os.setxattr(fp.fileno(), b"user.test", b"")
             except OSError:
                 return False
     finally:
-        support.unlink(support.TESTFN)
+        os_helper.unlink(os_helper.TESTFN)
 
     return True
 
@@ -3380,8 +3383,8 @@ def supports_extended_attributes():
 class ExtendedAttributeTests(unittest.TestCase):
 
     def _check_xattrs_str(self, s, getxattr, setxattr, removexattr, listxattr, **kwargs):
-        fn = support.TESTFN
-        self.addCleanup(support.unlink, fn)
+        fn = os_helper.TESTFN
+        self.addCleanup(os_helper.unlink, fn)
         create_file(fn)
 
         with self.assertRaises(OSError) as cm:
@@ -3429,10 +3432,10 @@ class ExtendedAttributeTests(unittest.TestCase):
 
     def _check_xattrs(self, *args, **kwargs):
         self._check_xattrs_str(str, *args, **kwargs)
-        support.unlink(support.TESTFN)
+        os_helper.unlink(os_helper.TESTFN)
 
         self._check_xattrs_str(os.fsencode, *args, **kwargs)
-        support.unlink(support.TESTFN)
+        os_helper.unlink(os_helper.TESTFN)
 
     def test_simple(self):
         self._check_xattrs(os.getxattr, os.setxattr, os.removexattr,
@@ -3531,16 +3534,16 @@ class OSErrorTests(unittest.TestCase):
 
         self.bytes_filenames = []
         self.unicode_filenames = []
-        if support.TESTFN_UNENCODABLE is not None:
-            decoded = support.TESTFN_UNENCODABLE
+        if os_helper.TESTFN_UNENCODABLE is not None:
+            decoded = os_helper.TESTFN_UNENCODABLE
         else:
-            decoded = support.TESTFN
+            decoded = os_helper.TESTFN
         self.unicode_filenames.append(decoded)
         self.unicode_filenames.append(Str(decoded))
-        if support.TESTFN_UNDECODABLE is not None:
-            encoded = support.TESTFN_UNDECODABLE
+        if os_helper.TESTFN_UNDECODABLE is not None:
+            encoded = os_helper.TESTFN_UNDECODABLE
         else:
-            encoded = os.fsencode(support.TESTFN)
+            encoded = os.fsencode(os_helper.TESTFN)
         self.bytes_filenames.append(encoded)
         self.bytes_filenames.append(bytearray(encoded))
         self.bytes_filenames.append(memoryview(encoded))
@@ -3734,14 +3737,14 @@ class PathTConverterTests(unittest.TestCase):
     ]
 
     def test_path_t_converter(self):
-        str_filename = support.TESTFN
+        str_filename = os_helper.TESTFN
         if os.name == 'nt':
             bytes_fspath = bytes_filename = None
         else:
-            bytes_filename = os.fsencode(support.TESTFN)
+            bytes_filename = os.fsencode(os_helper.TESTFN)
             bytes_fspath = FakePath(bytes_filename)
         fd = os.open(FakePath(str_filename), os.O_WRONLY|os.O_CREAT)
-        self.addCleanup(support.unlink, support.TESTFN)
+        self.addCleanup(os_helper.unlink, os_helper.TESTFN)
         self.addCleanup(os.close, fd)
 
         int_fspath = FakePath(fd)
@@ -3811,8 +3814,8 @@ class ExportsTests(unittest.TestCase):
 
 class TestDirEntry(unittest.TestCase):
     def setUp(self):
-        self.path = os.path.realpath(support.TESTFN)
-        self.addCleanup(support.rmtree, self.path)
+        self.path = os.path.realpath(os_helper.TESTFN)
+        self.addCleanup(os_helper.rmtree, self.path)
         os.mkdir(self.path)
 
     def test_uninstantiable(self):
@@ -3828,12 +3831,12 @@ class TestDirEntry(unittest.TestCase):
 
 
 class TestScandir(unittest.TestCase):
-    check_no_resource_warning = support.check_no_resource_warning
+    check_no_resource_warning = warnings_helper.check_no_resource_warning
 
     def setUp(self):
-        self.path = os.path.realpath(support.TESTFN)
+        self.path = os.path.realpath(os_helper.TESTFN)
         self.bytes_path = os.fsencode(self.path)
-        self.addCleanup(support.rmtree, self.path)
+        self.addCleanup(os_helper.rmtree, self.path)
         os.mkdir(self.path)
 
     def create_file(self, name="file.txt"):
@@ -3903,7 +3906,7 @@ class TestScandir(unittest.TestCase):
 
     def test_attributes(self):
         link = hasattr(os, 'link')
-        symlink = support.can_symlink()
+        symlink = os_helper.can_symlink()
 
         dirname = os.path.join(self.path, "dir")
         os.mkdir(dirname)
@@ -4027,7 +4030,7 @@ class TestScandir(unittest.TestCase):
             self.assertRaises(FileNotFoundError, entry.stat, follow_symlinks=False)
 
     def test_broken_symlink(self):
-        if not support.can_symlink():
+        if not os_helper.can_symlink():
             return self.skipTest('cannot create symbolic link')
 
         filename = self.create_file("file.txt")
@@ -4081,7 +4084,7 @@ class TestScandir(unittest.TestCase):
         self.assertIn(os.scandir, os.supports_fd)
         self.create_file('file.txt')
         expected_names = ['file.txt']
-        if support.can_symlink():
+        if os_helper.can_symlink():
             os.symlink('file.txt', os.path.join(self.path, 'link'))
             expected_names.append('link')
 
diff --git a/Lib/test/test_shutil.py b/Lib/test/test_shutil.py
index e56b337..06ca50a 100644
--- a/Lib/test/test_shutil.py
+++ b/Lib/test/test_shutil.py
@@ -30,7 +30,8 @@ except ImportError:
     posix = None
 
 from test import support
-from test.support import TESTFN, FakePath
+from test.support import os_helper
+from test.support.os_helper import TESTFN, FakePath
 
 TESTFN2 = TESTFN + "2"
 MACOS = sys.platform.startswith("darwin")
@@ -140,9 +141,9 @@ def supports_file2file_sendfile():
                     return True
     finally:
         if srcname is not None:
-            support.unlink(srcname)
+            os_helper.unlink(srcname)
         if dstname is not None:
-            support.unlink(dstname)
+            os_helper.unlink(dstname)
 
 
 SUPPORTS_SENDFILE = supports_file2file_sendfile()
@@ -168,7 +169,7 @@ class BaseTest:
         Returns the path of the directory.
         """
         d = tempfile.mkdtemp(prefix=prefix, dir=os.getcwd())
-        self.addCleanup(support.rmtree, d)
+        self.addCleanup(os_helper.rmtree, d)
         return d
 
 
@@ -183,7 +184,7 @@ class TestRmTree(BaseTest, unittest.TestCase):
         self.assertIsInstance(victim, bytes)
         shutil.rmtree(victim)
 
-    @support.skip_unless_symlink
+    @os_helper.skip_unless_symlink
     def test_rmtree_fails_on_symlink(self):
         tmp = self.mkdtemp()
         dir_ = os.path.join(tmp, 'dir')
@@ -202,7 +203,7 @@ class TestRmTree(BaseTest, unittest.TestCase):
         self.assertEqual(errors[0][1], link)
         self.assertIsInstance(errors[0][2][1], OSError)
 
-    @support.skip_unless_symlink
+    @os_helper.skip_unless_symlink
     def test_rmtree_works_on_symlinks(self):
         tmp = self.mkdtemp()
         dir1 = os.path.join(tmp, 'dir1')
@@ -231,7 +232,7 @@ class TestRmTree(BaseTest, unittest.TestCase):
         os.mkdir(dir_)
         link = os.path.join(tmp, 'link')
         _winapi.CreateJunction(dir_, link)
-        self.addCleanup(support.unlink, link)
+        self.addCleanup(os_helper.unlink, link)
         self.assertRaises(OSError, shutil.rmtree, link)
         self.assertTrue(os.path.exists(dir_))
         self.assertTrue(os.path.lexists(link))
@@ -313,7 +314,7 @@ class TestRmTree(BaseTest, unittest.TestCase):
 
         self.child_file_path = os.path.join(TESTFN, 'a')
         self.child_dir_path = os.path.join(TESTFN, 'b')
-        support.create_empty_file(self.child_file_path)
+        os_helper.create_empty_file(self.child_file_path)
         os.mkdir(self.child_dir_path)
         old_dir_mode = os.stat(TESTFN).st_mode
         old_child_file_mode = os.stat(self.child_file_path).st_mode
@@ -407,7 +408,7 @@ class TestRmTree(BaseTest, unittest.TestCase):
         self.assertRaises(NotADirectoryError, shutil.rmtree, path)
         os.remove(path)
 
-    @support.skip_unless_symlink
+    @os_helper.skip_unless_symlink
     def test_rmtree_on_symlink(self):
         # bug 1669.
         os.mkdir(TESTFN)
@@ -482,7 +483,7 @@ class TestCopyTree(BaseTest, unittest.TestCase):
         with self.assertRaises(FileExistsError):
             shutil.copytree(src_dir, dst_dir, dirs_exist_ok=False)
 
-    @support.skip_unless_symlink
+    @os_helper.skip_unless_symlink
     def test_copytree_symlinks(self):
         tmp_dir = self.mkdtemp()
         src_dir = os.path.join(tmp_dir, 'src')
@@ -634,7 +635,7 @@ class TestCopyTree(BaseTest, unittest.TestCase):
         write_file((src_dir, 'restrictive.txt'), '456')
         os.chmod(os.path.join(src_dir, 'restrictive.txt'), 0o600)
         restrictive_subdir = tempfile.mkdtemp(dir=src_dir)
-        self.addCleanup(support.rmtree, restrictive_subdir)
+        self.addCleanup(os_helper.rmtree, restrictive_subdir)
         os.chmod(restrictive_subdir, 0o600)
 
         shutil.copytree(src_dir, dst_dir)
@@ -681,7 +682,7 @@ class TestCopyTree(BaseTest, unittest.TestCase):
 
     # Issue #3002: copyfile and copytree block indefinitely on named pipes
     @unittest.skipUnless(hasattr(os, "mkfifo"), 'requires os.mkfifo()')
-    @support.skip_unless_symlink
+    @os_helper.skip_unless_symlink
     def test_copytree_named_pipe(self):
         os.mkdir(TESTFN)
         try:
@@ -719,7 +720,7 @@ class TestCopyTree(BaseTest, unittest.TestCase):
         shutil.copytree(src_dir, dst_dir, copy_function=_copy)
         self.assertEqual(len(copied), 2)
 
-    @support.skip_unless_symlink
+    @os_helper.skip_unless_symlink
     def test_copytree_dangling_symlinks(self):
         # a dangling symlink raises an error at the end
         src_dir = self.mkdtemp()
@@ -739,7 +740,7 @@ class TestCopyTree(BaseTest, unittest.TestCase):
         shutil.copytree(src_dir, dst_dir, symlinks=True)
         self.assertIn('test.txt', os.listdir(dst_dir))
 
-    @support.skip_unless_symlink
+    @os_helper.skip_unless_symlink
     def test_copytree_symlink_dir(self):
         src_dir = self.mkdtemp()
         dst_dir = os.path.join(self.mkdtemp(), 'destination')
@@ -785,7 +786,7 @@ class TestCopy(BaseTest, unittest.TestCase):
 
     ### shutil.copymode
 
-    @support.skip_unless_symlink
+    @os_helper.skip_unless_symlink
     def test_copymode_follow_symlinks(self):
         tmp_dir = self.mkdtemp()
         src = os.path.join(tmp_dir, 'foo')
@@ -818,7 +819,7 @@ class TestCopy(BaseTest, unittest.TestCase):
             self.assertEqual(os.stat(src).st_mode, os.stat(dst).st_mode)
 
     @unittest.skipUnless(hasattr(os, 'lchmod'), 'requires os.lchmod')
-    @support.skip_unless_symlink
+    @os_helper.skip_unless_symlink
     def test_copymode_symlink_to_symlink(self):
         tmp_dir = self.mkdtemp()
         src = os.path.join(tmp_dir, 'foo')
@@ -848,7 +849,7 @@ class TestCopy(BaseTest, unittest.TestCase):
         self.assertEqual(os.stat(src).st_mode, os.stat(dst).st_mode)
 
     @unittest.skipIf(hasattr(os, 'lchmod'), 'requires os.lchmod to be missing')
-    @support.skip_unless_symlink
+    @os_helper.skip_unless_symlink
     def test_copymode_symlink_to_symlink_wo_lchmod(self):
         tmp_dir = self.mkdtemp()
         src = os.path.join(tmp_dir, 'foo')
@@ -863,7 +864,7 @@ class TestCopy(BaseTest, unittest.TestCase):
 
     ### shutil.copystat
 
-    @support.skip_unless_symlink
+    @os_helper.skip_unless_symlink
     def test_copystat_symlinks(self):
         tmp_dir = self.mkdtemp()
         src = os.path.join(tmp_dir, 'foo')
@@ -935,7 +936,7 @@ class TestCopy(BaseTest, unittest.TestCase):
 
     ### shutil.copyxattr
 
-    @support.skip_unless_xattr
+    @os_helper.skip_unless_xattr
     def test_copyxattr(self):
         tmp_dir = self.mkdtemp()
         src = os.path.join(tmp_dir, 'foo')
@@ -999,8 +1000,8 @@ class TestCopy(BaseTest, unittest.TestCase):
         self.assertEqual(os.getxattr(dst, 'user.the_value'), b'fiddly')
         self.assertEqual(os.getxattr(dstro, 'user.the_value'), b'fiddly')
 
-    @support.skip_unless_symlink
-    @support.skip_unless_xattr
+    @os_helper.skip_unless_symlink
+    @os_helper.skip_unless_xattr
     @unittest.skipUnless(hasattr(os, 'geteuid') and os.geteuid() == 0,
                          'root privileges required')
     def test_copyxattr_symlinks(self):
@@ -1042,7 +1043,7 @@ class TestCopy(BaseTest, unittest.TestCase):
         self.assertTrue(os.path.exists(file2))
         self.assertEqual(os.stat(file1).st_mode, os.stat(file2).st_mode)
 
-    @support.skip_unless_symlink
+    @os_helper.skip_unless_symlink
     def test_copy_symlinks(self):
         tmp_dir = self.mkdtemp()
         src = os.path.join(tmp_dir, 'foo')
@@ -1084,7 +1085,7 @@ class TestCopy(BaseTest, unittest.TestCase):
             self.assertEqual(getattr(file1_stat, 'st_flags'),
                              getattr(file2_stat, 'st_flags'))
 
-    @support.skip_unless_symlink
+    @os_helper.skip_unless_symlink
     def test_copy2_symlinks(self):
         tmp_dir = self.mkdtemp()
         src = os.path.join(tmp_dir, 'foo')
@@ -1119,7 +1120,7 @@ class TestCopy(BaseTest, unittest.TestCase):
         if hasattr(os, 'lchflags') and hasattr(src_link_stat, 'st_flags'):
             self.assertEqual(src_link_stat.st_flags, dst_stat.st_flags)
 
-    @support.skip_unless_xattr
+    @os_helper.skip_unless_xattr
     def test_copy2_xattr(self):
         tmp_dir = self.mkdtemp()
         src = os.path.join(tmp_dir, 'foo')
@@ -1146,7 +1147,7 @@ class TestCopy(BaseTest, unittest.TestCase):
 
     ### shutil.copyfile
 
-    @support.skip_unless_symlink
+    @os_helper.skip_unless_symlink
     def test_copyfile_symlinks(self):
         tmp_dir = self.mkdtemp()
         src = os.path.join(tmp_dir, 'src')
@@ -1183,7 +1184,7 @@ class TestCopy(BaseTest, unittest.TestCase):
         finally:
             shutil.rmtree(TESTFN, ignore_errors=True)
 
-    @support.skip_unless_symlink
+    @os_helper.skip_unless_symlink
     def test_dont_copy_file_onto_symlink_to_itself(self):
         # bug 851123.
         os.mkdir(TESTFN)
@@ -1258,7 +1259,7 @@ class TestArchives(BaseTest, unittest.TestCase):
         work_dir = os.path.dirname(tmpdir2)
         rel_base_name = os.path.join(os.path.basename(tmpdir2), 'archive')
 
-        with support.change_cwd(work_dir):
+        with os_helper.change_cwd(work_dir):
             base_name = os.path.abspath(rel_base_name)
             tarball = make_archive(rel_base_name, 'gztar', root_dir, '.')
 
@@ -1272,7 +1273,7 @@ class TestArchives(BaseTest, unittest.TestCase):
                                    './file1', './file2', './sub/file3'])
 
         # trying an uncompressed one
-        with support.change_cwd(work_dir):
+        with os_helper.change_cwd(work_dir):
             tarball = make_archive(rel_base_name, 'tar', root_dir, '.')
         self.assertEqual(tarball, base_name + '.tar')
         self.assertTrue(os.path.isfile(tarball))
@@ -1347,7 +1348,7 @@ class TestArchives(BaseTest, unittest.TestCase):
         work_dir = os.path.dirname(tmpdir2)
         rel_base_name = os.path.join(os.path.basename(tmpdir2), 'archive')
 
-        with support.change_cwd(work_dir):
+        with os_helper.change_cwd(work_dir):
             base_name = os.path.abspath(rel_base_name)
             res = make_archive(rel_base_name, 'zip', root_dir)
 
@@ -1360,7 +1361,7 @@ class TestArchives(BaseTest, unittest.TestCase):
                      'dist/file1', 'dist/file2', 'dist/sub/file3',
                      'outer'])
 
-        with support.change_cwd(work_dir):
+        with os_helper.change_cwd(work_dir):
             base_name = os.path.abspath(rel_base_name)
             res = make_archive(rel_base_name, 'zip', root_dir, base_dir)
 
@@ -1412,7 +1413,7 @@ class TestArchives(BaseTest, unittest.TestCase):
 
         # now check the ZIP file using `unzip -t`
         zip_cmd = ['unzip', '-t', archive]
-        with support.change_cwd(root_dir):
+        with os_helper.change_cwd(root_dir):
             try:
                 subprocess.check_output(zip_cmd, stderr=subprocess.STDOUT)
             except subprocess.CalledProcessError as exc:
@@ -1462,7 +1463,7 @@ class TestArchives(BaseTest, unittest.TestCase):
         base_name = os.path.join(self.mkdtemp(), 'archive')
         group = grp.getgrgid(0)[0]
         owner = pwd.getpwuid(0)[0]
-        with support.change_cwd(root_dir):
+        with os_helper.change_cwd(root_dir):
             archive_name = make_archive(base_name, 'gztar', root_dir, 'dist',
                                         owner=owner, group=group)
 
@@ -1496,7 +1497,7 @@ class TestArchives(BaseTest, unittest.TestCase):
     def test_make_tarfile_in_curdir(self):
         # Issue #21280
         root_dir = self.mkdtemp()
-        with support.change_cwd(root_dir):
+        with os_helper.change_cwd(root_dir):
             self.assertEqual(make_archive('test', 'tar'), 'test.tar')
             self.assertTrue(os.path.isfile('test.tar'))
 
@@ -1504,7 +1505,7 @@ class TestArchives(BaseTest, unittest.TestCase):
     def test_make_zipfile_in_curdir(self):
         # Issue #21280
         root_dir = self.mkdtemp()
-        with support.change_cwd(root_dir):
+        with os_helper.change_cwd(root_dir):
             self.assertEqual(make_archive('test', 'zip'), 'test.zip')
             self.assertTrue(os.path.isfile('test.zip'))
 
@@ -1711,18 +1712,18 @@ class TestWhich(BaseTest, unittest.TestCase):
         # that exists, it should be returned.
         base_dir, tail_dir = os.path.split(self.dir)
         relpath = os.path.join(tail_dir, self.file)
-        with support.change_cwd(path=base_dir):
+        with os_helper.change_cwd(path=base_dir):
             rv = shutil.which(relpath, path=self.temp_dir)
             self.assertEqual(rv, relpath)
         # But it shouldn't be searched in PATH directories (issue #16957).
-        with support.change_cwd(path=self.dir):
+        with os_helper.change_cwd(path=self.dir):
             rv = shutil.which(relpath, path=base_dir)
             self.assertIsNone(rv)
 
     def test_cwd(self):
         # Issue #16957
         base_dir = os.path.dirname(self.dir)
-        with support.change_cwd(path=self.dir):
+        with os_helper.change_cwd(path=self.dir):
             rv = shutil.which(self.file, path=base_dir)
             if sys.platform == "win32":
                 # Windows: current directory implicitly on PATH
@@ -1743,7 +1744,7 @@ class TestWhich(BaseTest, unittest.TestCase):
 
     def test_relative_path(self):
         base_dir, tail_dir = os.path.split(self.dir)
-        with support.change_cwd(path=base_dir):
+        with os_helper.change_cwd(path=base_dir):
             rv = shutil.which(self.file, path=tail_dir)
             self.assertEqual(rv, os.path.join(tail_dir, self.file))
 
@@ -1761,19 +1762,19 @@ class TestWhich(BaseTest, unittest.TestCase):
         self.assertEqual(rv, self.temp_file.name[:-4] + self.ext)
 
     def test_environ_path(self):
-        with support.EnvironmentVarGuard() as env:
+        with os_helper.EnvironmentVarGuard() as env:
             env['PATH'] = self.env_path
             rv = shutil.which(self.file)
             self.assertEqual(rv, self.temp_file.name)
 
     def test_environ_path_empty(self):
         # PATH='': no match
-        with support.EnvironmentVarGuard() as env:
+        with os_helper.EnvironmentVarGuard() as env:
             env['PATH'] = ''
             with unittest.mock.patch('os.confstr', return_value=self.dir, \
                                      create=True), \
                  support.swap_attr(os, 'defpath', self.dir), \
-                 support.change_cwd(self.dir):
+                 os_helper.change_cwd(self.dir):
                 rv = shutil.which(self.file)
                 self.assertIsNone(rv)
 
@@ -1786,7 +1787,7 @@ class TestWhich(BaseTest, unittest.TestCase):
             expected_cwd = os.path.join(curdir, expected_cwd)
 
         # PATH=':': explicitly looks in the current directory
-        with support.EnvironmentVarGuard() as env:
+        with os_helper.EnvironmentVarGuard() as env:
             env['PATH'] = os.pathsep
             with unittest.mock.patch('os.confstr', return_value=self.dir, \
                                      create=True), \
@@ -1795,12 +1796,12 @@ class TestWhich(BaseTest, unittest.TestCase):
                 self.assertIsNone(rv)
 
                 # look in current directory
-                with support.change_cwd(self.dir):
+                with os_helper.change_cwd(self.dir):
                     rv = shutil.which(self.file)
                     self.assertEqual(rv, expected_cwd)
 
     def test_environ_path_missing(self):
-        with support.EnvironmentVarGuard() as env:
+        with os_helper.EnvironmentVarGuard() as env:
             env.pop('PATH', None)
 
             # without confstr
@@ -1819,14 +1820,14 @@ class TestWhich(BaseTest, unittest.TestCase):
 
     def test_empty_path(self):
         base_dir = os.path.dirname(self.dir)
-        with support.change_cwd(path=self.dir), \
-             support.EnvironmentVarGuard() as env:
+        with os_helper.change_cwd(path=self.dir), \
+             os_helper.EnvironmentVarGuard() as env:
             env['PATH'] = self.env_path
             rv = shutil.which(self.file, path='')
             self.assertIsNone(rv)
 
     def test_empty_path_no_PATH(self):
-        with support.EnvironmentVarGuard() as env:
+        with os_helper.EnvironmentVarGuard() as env:
             env.pop('PATH', None)
             rv = shutil.which(self.file)
             self.assertIsNone(rv)
@@ -1843,7 +1844,7 @@ class TestWhich(BaseTest, unittest.TestCase):
         program = os.path.basename(temp_filexyz.name)
         program = os.path.splitext(program)[0]
 
-        with support.EnvironmentVarGuard() as env:
+        with os_helper.EnvironmentVarGuard() as env:
             env['PATHEXT'] = ext
             rv = shutil.which(program, path=self.temp_dir)
             self.assertEqual(rv, temp_filexyz.name)
@@ -1918,7 +1919,7 @@ class TestMove(BaseTest, unittest.TestCase):
         try:
             self._check_move_dir(self.src_dir, dst_dir, dst_dir)
         finally:
-            support.rmtree(dst_dir)
+            os_helper.rmtree(dst_dir)
 
     @mock_rename
     def test_move_dir_other_fs(self):
@@ -1965,7 +1966,7 @@ class TestMove(BaseTest, unittest.TestCase):
                              msg='_destinsrc() wrongly concluded that '
                              'dst (%s) is not in src (%s)' % (dst, src))
         finally:
-            support.rmtree(TESTFN)
+            os_helper.rmtree(TESTFN)
 
     def test_destinsrc_false_positive(self):
         os.mkdir(TESTFN)
@@ -1977,9 +1978,9 @@ class TestMove(BaseTest, unittest.TestCase):
                             msg='_destinsrc() wrongly concluded that '
                             'dst (%s) is in src (%s)' % (dst, src))
         finally:
-            support.rmtree(TESTFN)
+            os_helper.rmtree(TESTFN)
 
-    @support.skip_unless_symlink
+    @os_helper.skip_unless_symlink
     @mock_rename
     def test_move_file_symlink(self):
         dst = os.path.join(self.src_dir, 'bar')
@@ -1988,7 +1989,7 @@ class TestMove(BaseTest, unittest.TestCase):
         self.assertTrue(os.path.islink(self.dst_file))
         self.assertTrue(os.path.samefile(self.src_file, self.dst_file))
 
-    @support.skip_unless_symlink
+    @os_helper.skip_unless_symlink
     @mock_rename
     def test_move_file_symlink_to_dir(self):
         filename = "bar"
@@ -1999,7 +2000,7 @@ class TestMove(BaseTest, unittest.TestCase):
         self.assertTrue(os.path.islink(final_link))
         self.assertTrue(os.path.samefile(self.src_file, final_link))
 
-    @support.skip_unless_symlink
+    @os_helper.skip_unless_symlink
     @mock_rename
     def test_move_dangling_symlink(self):
         src = os.path.join(self.src_dir, 'baz')
@@ -2010,7 +2011,7 @@ class TestMove(BaseTest, unittest.TestCase):
         self.assertTrue(os.path.islink(dst_link))
         self.assertEqual(os.path.realpath(src), os.path.realpath(dst_link))
 
-    @support.skip_unless_symlink
+    @os_helper.skip_unless_symlink
     @mock_rename
     def test_move_dir_symlink(self):
         src = os.path.join(self.src_dir, 'baz')
@@ -2044,8 +2045,8 @@ class TestMove(BaseTest, unittest.TestCase):
         moved = []
         def _copy(src, dst):
             moved.append((src, dst))
-        support.create_empty_file(os.path.join(self.src_dir, 'child'))
-        support.create_empty_file(os.path.join(self.src_dir, 'child1'))
+        os_helper.create_empty_file(os.path.join(self.src_dir, 'child'))
+        os_helper.create_empty_file(os.path.join(self.src_dir, 'child1'))
         shutil.move(self.src_dir, self.dst_dir, copy_function=_copy)
         self.assertEqual(len(moved), 3)
 
@@ -2167,11 +2168,11 @@ class TestCopyFileObj(unittest.TestCase):
 
     @classmethod
     def tearDownClass(cls):
-        support.unlink(TESTFN)
-        support.unlink(TESTFN2)
+        os_helper.unlink(TESTFN)
+        os_helper.unlink(TESTFN2)
 
     def tearDown(self):
-        support.unlink(TESTFN2)
+        os_helper.unlink(TESTFN2)
 
     @contextlib.contextmanager
     def get_files(self):
@@ -2216,7 +2217,7 @@ class TestCopyFileObj(unittest.TestCase):
         with tempfile.NamedTemporaryFile(dir=os.getcwd(), delete=False) as f:
             f.write(b'foo')
         fname = f.name
-        self.addCleanup(support.unlink, fname)
+        self.addCleanup(os_helper.unlink, fname)
         with unittest.mock.patch("shutil._copyfileobj_readinto") as m:
             shutil.copyfile(fname, TESTFN2)
         self.assertEqual(m.call_args[0][2], 3)
@@ -2225,7 +2226,7 @@ class TestCopyFileObj(unittest.TestCase):
         with tempfile.NamedTemporaryFile(dir=os.getcwd(), delete=False) as f:
             pass
         fname = f.name
-        self.addCleanup(support.unlink, fname)
+        self.addCleanup(os_helper.unlink, fname)
         with unittest.mock.patch("shutil._copyfileobj_readinto") as m:
             shutil.copyfile(fname, TESTFN2)
         assert not m.called
@@ -2247,10 +2248,10 @@ class _ZeroCopyFileTest(object):
 
     @classmethod
     def tearDownClass(cls):
-        support.unlink(TESTFN)
+        os_helper.unlink(TESTFN)
 
     def tearDown(self):
-        support.unlink(TESTFN2)
+        os_helper.unlink(TESTFN2)
 
     @contextlib.contextmanager
     def get_files(self):
@@ -2296,8 +2297,8 @@ class _ZeroCopyFileTest(object):
     def test_empty_file(self):
         srcname = TESTFN + 'src'
         dstname = TESTFN + 'dst'
-        self.addCleanup(lambda: support.unlink(srcname))
-        self.addCleanup(lambda: support.unlink(dstname))
+        self.addCleanup(lambda: os_helper.unlink(srcname))
+        self.addCleanup(lambda: os_helper.unlink(dstname))
         with open(srcname, "wb"):
             pass
 
@@ -2421,9 +2422,9 @@ class TestZeroCopySendfile(_ZeroCopyFileTest, unittest.TestCase):
             # sendfile() are the same.
             self.assertEqual(blocksize, os.path.getsize(TESTFN))
             # ...unless we're dealing with a small file.
-            support.unlink(TESTFN2)
+            os_helper.unlink(TESTFN2)
             write_file(TESTFN2, b"hello", binary=True)
-            self.addCleanup(support.unlink, TESTFN2 + '3')
+            self.addCleanup(os_helper.unlink, TESTFN2 + '3')
             self.assertRaises(ZeroDivisionError,
                               shutil.copyfile, TESTFN2, TESTFN2 + '3')
             blocksize = m.call_args[0][3]
@@ -2473,20 +2474,20 @@ class TestGetTerminalSize(unittest.TestCase):
     def test_os_environ_first(self):
         "Check if environment variables have precedence"
 
-        with support.EnvironmentVarGuard() as env:
+        with os_helper.EnvironmentVarGuard() as env:
             env['COLUMNS'] = '777'
             del env['LINES']
             size = shutil.get_terminal_size()
         self.assertEqual(size.columns, 777)
 
-        with support.EnvironmentVarGuard() as env:
+        with os_helper.EnvironmentVarGuard() as env:
             del env['COLUMNS']
             env['LINES'] = '888'
             size = shutil.get_terminal_size()
         self.assertEqual(size.lines, 888)
 
     def test_bad_environ(self):
-        with support.EnvironmentVarGuard() as env:
+        with os_helper.EnvironmentVarGuard() as env:
             env['COLUMNS'] = 'xxx'
             env['LINES'] = 'yyy'
             size = shutil.get_terminal_size()
@@ -2510,7 +2511,7 @@ class TestGetTerminalSize(unittest.TestCase):
             self.skipTest("stty invocation failed")
         expected = (int(size[1]), int(size[0])) # reversed order
 
-        with support.EnvironmentVarGuard() as env:
+        with os_helper.EnvironmentVarGuard() as env:
             del env['LINES']
             del env['COLUMNS']
             actual = shutil.get_terminal_size()
@@ -2518,7 +2519,7 @@ class TestGetTerminalSize(unittest.TestCase):
         self.assertEqual(expected, actual)
 
     def test_fallback(self):
-        with support.EnvironmentVarGuard() as env:
+        with os_helper.EnvironmentVarGuard() as env:
             del env['LINES']
             del env['COLUMNS']
 
diff --git a/Lib/test/test_subprocess.py b/Lib/test/test_subprocess.py
index aced876..0162424 100644
--- a/Lib/test/test_subprocess.py
+++ b/Lib/test/test_subprocess.py
@@ -1,6 +1,9 @@
 import unittest
 from unittest import mock
 from test import support
+from test.support import import_helper
+from test.support import os_helper
+from test.support import warnings_helper
 import subprocess
 import sys
 import signal
@@ -20,7 +23,7 @@ import threading
 import gc
 import textwrap
 import json
-from test.support import FakePath
+from test.support.os_helper import FakePath
 
 try:
     import _testcapi
@@ -357,7 +360,7 @@ class ProcessTestCase(BaseTestCase):
         # Normalize an expected cwd (for Tru64 support).
         # We can't use os.path.realpath since it doesn't expand Tru64 {memb}
         # strings.  See bug #1063571.
-        with support.change_cwd(cwd):
+        with os_helper.change_cwd(cwd):
             return os.getcwd()
 
     # For use in the test_cwd* tests below.
@@ -406,7 +409,7 @@ class ProcessTestCase(BaseTestCase):
         # is relative.
         python_dir, python_base = self._split_python_path()
         rel_python = os.path.join(os.curdir, python_base)
-        with support.temp_cwd() as wrong_dir:
+        with os_helper.temp_cwd() as wrong_dir:
             # Before calling with the correct cwd, confirm that the call fails
             # without cwd and with the wrong cwd.
             self.assertRaises(FileNotFoundError, subprocess.Popen,
@@ -423,7 +426,7 @@ class ProcessTestCase(BaseTestCase):
         python_dir, python_base = self._split_python_path()
         rel_python = os.path.join(os.curdir, python_base)
         doesntexist = "somethingyoudonthave"
-        with support.temp_cwd() as wrong_dir:
+        with os_helper.temp_cwd() as wrong_dir:
             # Before calling with the correct cwd, confirm that the call fails
             # without cwd and with the wrong cwd.
             self.assertRaises(FileNotFoundError, subprocess.Popen,
@@ -441,7 +444,7 @@ class ProcessTestCase(BaseTestCase):
         python_dir, python_base = self._split_python_path()
         abs_python = os.path.join(python_dir, python_base)
         rel_python = os.path.join(os.curdir, python_base)
-        with support.temp_dir() as wrong_dir:
+        with os_helper.temp_dir() as wrong_dir:
             # Before calling with an absolute path, confirm that using a
             # relative path fails.
             self.assertRaises(FileNotFoundError, subprocess.Popen,
@@ -1052,7 +1055,7 @@ class ProcessTestCase(BaseTestCase):
         try:
             for i in range(max_handles):
                 try:
-                    tmpfile = os.path.join(tmpdir, support.TESTFN)
+                    tmpfile = os.path.join(tmpdir, os_helper.TESTFN)
                     handles.append(os.open(tmpfile, os.O_WRONLY|os.O_CREAT))
                 except OSError as e:
                     if e.errno != errno.EMFILE:
@@ -2881,7 +2884,7 @@ class POSIXProcessTestCase(BaseTestCase):
     def test_select_unbuffered(self):
         # Issue #11459: bufsize=0 should really set the pipes as
         # unbuffered (and therefore let select() work properly).
-        select = support.import_module("select")
+        select = import_helper.import_module("select")
         p = subprocess.Popen([sys.executable, "-c",
                               'import sys;'
                               'sys.stdout.write("apple")'],
@@ -2909,7 +2912,7 @@ class POSIXProcessTestCase(BaseTestCase):
         self.addCleanup(p.stderr.close)
         ident = id(p)
         pid = p.pid
-        with support.check_warnings(('', ResourceWarning)):
+        with warnings_helper.check_warnings(('', ResourceWarning)):
             p = None
 
         if mswindows:
@@ -2934,7 +2937,7 @@ class POSIXProcessTestCase(BaseTestCase):
         self.addCleanup(p.stderr.close)
         ident = id(p)
         pid = p.pid
-        with support.check_warnings(('', ResourceWarning)):
+        with warnings_helper.check_warnings(('', ResourceWarning)):
             p = None
 
         os.kill(pid, signal.SIGKILL)
@@ -3288,7 +3291,8 @@ class Win32ProcessTestCase(BaseTestCase):
         self.assertIn(b"OSError", stderr)
 
         # Check for a warning due to using handle_list and close_fds=False
-        with support.check_warnings((".*overriding close_fds", RuntimeWarning)):
+        with warnings_helper.check_warnings((".*overriding close_fds",
+                                             RuntimeWarning)):
             startupinfo = subprocess.STARTUPINFO()
             startupinfo.lpAttributeList = {"handle_list": handles[:]}
             p = subprocess.Popen([sys.executable, "-c",
diff --git a/Lib/test/test_support.py b/Lib/test/test_support.py
index a7d5b1b..b268511 100644
--- a/Lib/test/test_support.py
+++ b/Lib/test/test_support.py
@@ -12,20 +12,24 @@ import textwrap
 import time
 import unittest
 from test import support
+from test.support import import_helper
+from test.support import os_helper
 from test.support import script_helper
 from test.support import socket_helper
+from test.support import warnings_helper
 
-TESTFN = support.TESTFN
+TESTFN = os_helper.TESTFN
 
 
 class TestSupport(unittest.TestCase):
 
     def test_import_module(self):
-        support.import_module("ftplib")
-        self.assertRaises(unittest.SkipTest, support.import_module, "foo")
+        import_helper.import_module("ftplib")
+        self.assertRaises(unittest.SkipTest,
+                          import_helper.import_module, "foo")
 
     def test_import_fresh_module(self):
-        support.import_fresh_module("ftplib")
+        import_helper.import_fresh_module("ftplib")
 
     def test_get_attribute(self):
         self.assertEqual(support.get_attribute(self, "test_get_attribute"),
@@ -39,38 +43,38 @@ class TestSupport(unittest.TestCase):
     def test_unload(self):
         import sched
         self.assertIn("sched", sys.modules)
-        support.unload("sched")
+        import_helper.unload("sched")
         self.assertNotIn("sched", sys.modules)
 
     def test_unlink(self):
         with open(TESTFN, "w") as f:
             pass
-        support.unlink(TESTFN)
+        os_helper.unlink(TESTFN)
         self.assertFalse(os.path.exists(TESTFN))
-        support.unlink(TESTFN)
+        os_helper.unlink(TESTFN)
 
     def test_rmtree(self):
-        dirpath = support.TESTFN + 'd'
+        dirpath = os_helper.TESTFN + 'd'
         subdirpath = os.path.join(dirpath, 'subdir')
         os.mkdir(dirpath)
         os.mkdir(subdirpath)
-        support.rmtree(dirpath)
+        os_helper.rmtree(dirpath)
         self.assertFalse(os.path.exists(dirpath))
         with support.swap_attr(support, 'verbose', 0):
-            support.rmtree(dirpath)
+            os_helper.rmtree(dirpath)
 
         os.mkdir(dirpath)
         os.mkdir(subdirpath)
         os.chmod(dirpath, stat.S_IRUSR|stat.S_IXUSR)
         with support.swap_attr(support, 'verbose', 0):
-            support.rmtree(dirpath)
+            os_helper.rmtree(dirpath)
         self.assertFalse(os.path.exists(dirpath))
 
         os.mkdir(dirpath)
         os.mkdir(subdirpath)
         os.chmod(dirpath, 0)
         with support.swap_attr(support, 'verbose', 0):
-            support.rmtree(dirpath)
+            os_helper.rmtree(dirpath)
         self.assertFalse(os.path.exists(dirpath))
 
     def test_forget(self):
@@ -83,12 +87,12 @@ class TestSupport(unittest.TestCase):
             mod = __import__(TESTFN)
             self.assertIn(TESTFN, sys.modules)
 
-            support.forget(TESTFN)
+            import_helper.forget(TESTFN)
             self.assertNotIn(TESTFN, sys.modules)
         finally:
             del sys.path[0]
-            support.unlink(mod_filename)
-            support.rmtree('__pycache__')
+            os_helper.unlink(mod_filename)
+            os_helper.rmtree('__pycache__')
 
     def test_HOST(self):
         s = socket.create_server((socket_helper.HOST, 0))
@@ -115,23 +119,23 @@ class TestSupport(unittest.TestCase):
         try:
             path = os.path.join(parent_dir, 'temp')
             self.assertFalse(os.path.isdir(path))
-            with support.temp_dir(path) as temp_path:
+            with os_helper.temp_dir(path) as temp_path:
                 self.assertEqual(temp_path, path)
                 self.assertTrue(os.path.isdir(path))
             self.assertFalse(os.path.isdir(path))
         finally:
-            support.rmtree(parent_dir)
+            os_helper.rmtree(parent_dir)
 
     def test_temp_dir__path_none(self):
         """Test passing no path."""
-        with support.temp_dir() as temp_path:
+        with os_helper.temp_dir() as temp_path:
             self.assertTrue(os.path.isdir(temp_path))
         self.assertFalse(os.path.isdir(temp_path))
 
     def test_temp_dir__existing_dir__quiet_default(self):
         """Test passing a directory that already exists."""
         def call_temp_dir(path):
-            with support.temp_dir(path) as temp_path:
+            with os_helper.temp_dir(path) as temp_path:
                 raise Exception("should not get here")
 
         path = tempfile.mkdtemp()
@@ -150,8 +154,8 @@ class TestSupport(unittest.TestCase):
         path = os.path.realpath(path)
 
         try:
-            with support.check_warnings() as recorder:
-                with support.temp_dir(path, quiet=True) as temp_path:
+            with warnings_helper.check_warnings() as recorder:
+                with os_helper.temp_dir(path, quiet=True) as temp_path:
                     self.assertEqual(path, temp_path)
                 warnings = [str(w.message) for w in recorder.warnings]
             # Make sure temp_dir did not delete the original directory.
@@ -173,7 +177,8 @@ class TestSupport(unittest.TestCase):
         script_helper.assert_python_ok("-c", textwrap.dedent("""
             import os
             from test import support
-            with support.temp_cwd() as temp_path:
+            from test.support import os_helper
+            with os_helper.temp_cwd() as temp_path:
                 pid = os.fork()
                 if pid != 0:
                     # parent process
@@ -194,8 +199,8 @@ class TestSupport(unittest.TestCase):
     def test_change_cwd(self):
         original_cwd = os.getcwd()
 
-        with support.temp_dir() as temp_path:
-            with support.change_cwd(temp_path) as new_cwd:
+        with os_helper.temp_dir() as temp_path:
+            with os_helper.change_cwd(temp_path) as new_cwd:
                 self.assertEqual(new_cwd, temp_path)
                 self.assertEqual(os.getcwd(), new_cwd)
 
@@ -206,10 +211,10 @@ class TestSupport(unittest.TestCase):
         original_cwd = os.getcwd()
 
         def call_change_cwd(path):
-            with support.change_cwd(path) as new_cwd:
+            with os_helper.change_cwd(path) as new_cwd:
                 raise Exception("should not get here")
 
-        with support.temp_dir() as parent_dir:
+        with os_helper.temp_dir() as parent_dir:
             non_existent_dir = os.path.join(parent_dir, 'does_not_exist')
             self.assertRaises(FileNotFoundError, call_change_cwd,
                               non_existent_dir)
@@ -220,10 +225,10 @@ class TestSupport(unittest.TestCase):
         """Test passing a non-existent directory with quiet=True."""
         original_cwd = os.getcwd()
 
-        with support.temp_dir() as parent_dir:
+        with os_helper.temp_dir() as parent_dir:
             bad_dir = os.path.join(parent_dir, 'does_not_exist')
-            with support.check_warnings() as recorder:
-                with support.change_cwd(bad_dir, quiet=True) as new_cwd:
+            with warnings_helper.check_warnings() as recorder:
+                with os_helper.change_cwd(bad_dir, quiet=True) as new_cwd:
                     self.assertEqual(new_cwd, original_cwd)
                     self.assertEqual(os.getcwd(), new_cwd)
                 warnings = [str(w.message) for w in recorder.warnings]
@@ -240,8 +245,8 @@ class TestSupport(unittest.TestCase):
     def test_change_cwd__chdir_warning(self):
         """Check the warning message when os.chdir() fails."""
         path = TESTFN + '_does_not_exist'
-        with support.check_warnings() as recorder:
-            with support.change_cwd(path=path, quiet=True):
+        with warnings_helper.check_warnings() as recorder:
+            with os_helper.change_cwd(path=path, quiet=True):
                 pass
             messages = [str(w.message) for w in recorder.warnings]
 
@@ -256,7 +261,7 @@ class TestSupport(unittest.TestCase):
 
     def test_temp_cwd(self):
         here = os.getcwd()
-        with support.temp_cwd(name=TESTFN):
+        with os_helper.temp_cwd(name=TESTFN):
             self.assertEqual(os.path.basename(os.getcwd()), TESTFN)
         self.assertFalse(os.path.exists(TESTFN))
         self.assertEqual(os.getcwd(), here)
@@ -265,7 +270,7 @@ class TestSupport(unittest.TestCase):
     def test_temp_cwd__name_none(self):
         """Test passing None to temp_cwd()."""
         original_cwd = os.getcwd()
-        with support.temp_cwd(name=None) as new_cwd:
+        with os_helper.temp_cwd(name=None) as new_cwd:
             self.assertNotEqual(new_cwd, original_cwd)
             self.assertTrue(os.path.isdir(new_cwd))
             self.assertEqual(os.getcwd(), new_cwd)
@@ -275,7 +280,7 @@ class TestSupport(unittest.TestCase):
         self.assertEqual(support.sortdict({3:3, 2:2, 1:1}), "{1: 1, 2: 2, 3: 3}")
 
     def test_make_bad_fd(self):
-        fd = support.make_bad_fd()
+        fd = os_helper.make_bad_fd()
         with self.assertRaises(OSError) as cm:
             os.write(fd, b"foo")
         self.assertEqual(cm.exception.errno, errno.EBADF)
@@ -287,11 +292,11 @@ class TestSupport(unittest.TestCase):
 
     def test_CleanImport(self):
         import importlib
-        with support.CleanImport("asyncore"):
+        with import_helper.CleanImport("asyncore"):
             importlib.import_module("asyncore")
 
     def test_DirsOnSysPath(self):
-        with support.DirsOnSysPath('foo', 'bar'):
+        with import_helper.DirsOnSysPath('foo', 'bar'):
             self.assertIn("foo", sys.path)
             self.assertIn("bar", sys.path)
         self.assertNotIn("foo", sys.path)
@@ -625,10 +630,10 @@ class TestSupport(unittest.TestCase):
         # We cannot test the absolute value of fd_count(): on old Linux
         # kernel or glibc versions, os.urandom() keeps a FD open on
         # /dev/urandom device and Python has 4 FD opens instead of 3.
-        start = support.fd_count()
+        start = os_helper.fd_count()
         fd = os.open(__file__, os.O_RDONLY)
         try:
-            more = support.fd_count()
+            more = os_helper.fd_count()
         finally:
             os.close(fd)
         self.assertEqual(more - start, 1)
diff --git a/Lib/test/test_tempfile.py b/Lib/test/test_tempfile.py
index fcc706e..8ace883 100644
--- a/Lib/test/test_tempfile.py
+++ b/Lib/test/test_tempfile.py
@@ -15,7 +15,9 @@ from unittest import mock
 
 import unittest
 from test import support
+from test.support import os_helper
 from test.support import script_helper
+from test.support import warnings_helper
 
 
 has_textmode = (tempfile._text_openflags != tempfile._bin_openflags)
@@ -69,7 +71,7 @@ class BaseTestCase(unittest.TestCase):
     b_check = re.compile(br"^[a-z0-9_-]{8}$")
 
     def setUp(self):
-        self._warnings_manager = support.check_warnings()
+        self._warnings_manager = warnings_helper.check_warnings()
         self._warnings_manager.__enter__()
         warnings.filterwarnings("ignore", category=RuntimeWarning,
                                 message="mktemp", module=__name__)
@@ -224,7 +226,7 @@ class TestCandidateTempdirList(BaseTestCase):
         # _candidate_tempdir_list contains the expected directories
 
         # Make sure the interesting environment variables are all set.
-        with support.EnvironmentVarGuard() as env:
+        with os_helper.EnvironmentVarGuard() as env:
             for envname in 'TMPDIR', 'TEMP', 'TMP':
                 dirname = os.getenv(envname)
                 if not dirname:
@@ -310,7 +312,7 @@ def _inside_empty_temp_dir():
         with support.swap_attr(tempfile, 'tempdir', dir):
             yield
     finally:
-        support.rmtree(dir)
+        os_helper.rmtree(dir)
 
 
 def _mock_candidate_names(*names):
@@ -594,13 +596,13 @@ class TestGetTempDir(BaseTestCase):
         case_sensitive_tempdir = tempfile.mkdtemp("-Temp")
         _tempdir, tempfile.tempdir = tempfile.tempdir, None
         try:
-            with support.EnvironmentVarGuard() as env:
+            with os_helper.EnvironmentVarGuard() as env:
                 # Fake the first env var which is checked as a candidate
                 env["TMPDIR"] = case_sensitive_tempdir
                 self.assertEqual(tempfile.gettempdir(), case_sensitive_tempdir)
         finally:
             tempfile.tempdir = _tempdir
-            support.rmdir(case_sensitive_tempdir)
+            os_helper.rmdir(case_sensitive_tempdir)
 
 
 class TestMkstemp(BaseTestCase):
@@ -950,7 +952,7 @@ class TestNamedTemporaryFile(BaseTestCase):
 
     def test_bad_mode(self):
         dir = tempfile.mkdtemp()
-        self.addCleanup(support.rmtree, dir)
+        self.addCleanup(os_helper.rmtree, dir)
         with self.assertRaises(ValueError):
             tempfile.NamedTemporaryFile(mode='wr', dir=dir)
         with self.assertRaises(TypeError):
@@ -1351,7 +1353,7 @@ class TestTemporaryDirectory(BaseTestCase):
         finally:
             os.rmdir(dir)
 
-    @support.skip_unless_symlink
+    @os_helper.skip_unless_symlink
     def test_cleanup_with_symlink_to_a_directory(self):
         # cleanup() should not follow symlinks to directories (issue #12464)
         d1 = self.do_create()
@@ -1448,7 +1450,9 @@ class TestTemporaryDirectory(BaseTestCase):
             name = d.name
 
             # Check for the resource warning
-            with support.check_warnings(('Implicitly', ResourceWarning), quiet=False):
+            with warnings_helper.check_warnings(('Implicitly',
+                                                 ResourceWarning),
+                                                quiet=False):
                 warnings.filterwarnings("always", category=ResourceWarning)
                 del d
                 support.gc_collect()