add __all__ to test_support

Lib/test/test___all__.py

@@ -144,6 +144,7 @@ class AllTest(unittest.TestCase):
         self.check_all("tarfile")
         self.check_all("telnetlib")
         self.check_all("tempfile")
+        self.check_all("test.test_support")
         self.check_all("textwrap")
         self.check_all("threading")
         self.check_all("timeit")

Lib/test/test_support.py

@@ -13,6 +13,19 @@ import shutil
 import warnings
 import unittest
 
+__all__ = ["Error", "TestFailed", "TestSkipped", "ResourceDenied", "import_module",
+           "verbose", "use_resources", "max_memuse", "record_original_stdout",
+           "get_original_stdout", "unload", "unlink", "rmtree", "forget",
+           "is_resource_enabled", "requires", "find_unused_port", "bind_port",
+           "fcmp", "have_unicode", "is_jython", "TESTFN", "HOST", "FUZZ",
+           "findfile", "verify", "vereq", "sortdict", "check_syntax_error",
+           "open_urlresource", "WarningMessage", "catch_warning", "CleanImport",
+           "EnvironmentVarGuard", "TransientResource", "captured_output",
+           "captured_stdout", "TransientResource", "transient_internet",
+           "run_with_locale", "set_memlimit", "bigmemtest", "bigaddrspacetest",
+           "BasicTestRunner", "run_unittest", "run_doctest", "threading_setup",
+           "threading_cleanup", "reap_children"]
+
 class Error(Exception):
     """Base class for regression test exceptions."""