bpo-40275: Use new test.support helper submodules in tests (GH-21314)

diff --git a/Lib/test/test_binhex.py b/Lib/test/test_binhex.py
index 591f32a..5e59f57 100644
--- a/Lib/test/test_binhex.py
+++ b/Lib/test/test_binhex.py
@@ -5,23 +5,27 @@
 """
 import unittest
 from test import support
+from test.support import import_helper
+from test.support import os_helper
+from test.support import warnings_helper
 
-with support.check_warnings(('', DeprecationWarning)):
-    binhex = support.import_fresh_module('binhex')
+
+with warnings_helper.check_warnings(('', DeprecationWarning)):
+    binhex = import_helper.import_fresh_module('binhex')
 
 
 class BinHexTestCase(unittest.TestCase):
 
     def setUp(self):
         # binhex supports only file names encodable to Latin1
-        self.fname1 = support.TESTFN_ASCII + "1"
-        self.fname2 = support.TESTFN_ASCII + "2"
-        self.fname3 = support.TESTFN_ASCII + "very_long_filename__very_long_filename__very_long_filename__very_long_filename__"
+        self.fname1 = os_helper.TESTFN_ASCII + "1"
+        self.fname2 = os_helper.TESTFN_ASCII + "2"
+        self.fname3 = os_helper.TESTFN_ASCII + "very_long_filename__very_long_filename__very_long_filename__very_long_filename__"
 
     def tearDown(self):
-        support.unlink(self.fname1)
-        support.unlink(self.fname2)
-        support.unlink(self.fname3)
+        os_helper.unlink(self.fname1)
+        os_helper.unlink(self.fname2)
+        os_helper.unlink(self.fname3)
 
     DATA = b'Jack is my hero'