diff --git a/Lib/test/regrtest.py b/Lib/test/regrtest.py
--- a/Lib/test/regrtest.py
+++ b/Lib/test/regrtest.py
@@ -654,6 +654,7 @@
     test_times = []
     support.verbose = verbose      # Tell tests to be moderately quiet
     support.use_resources = use_resources
+    support.regrtest_run = True    # Tell tests that regrtest is is control
     save_modules = sys.modules.keys()
 
     def accumulate_result(test, result):
diff --git a/Lib/test/support.py b/Lib/test/support.py
--- a/Lib/test/support.py
+++ b/Lib/test/support.py
@@ -59,7 +59,7 @@
 
 __all__ = [
     "Error", "TestFailed", "ResourceDenied", "import_module", "verbose",
-    "use_resources", "max_memuse", "record_original_stdout",
+    "use_resources", "regrtest_run", "max_memuse", "record_original_stdout",
     "get_original_stdout", "unload", "unlink", "rmtree", "forget",
     "is_resource_enabled", "requires", "requires_freebsd_version",
     "requires_linux_version", "requires_mac_ver", "find_unused_port",
@@ -214,6 +214,7 @@
 
 verbose = 1              # Flag set to 0 by regrtest.py
 use_resources = None     # Flag set to [] by regrtest.py
+regrtest_run = False     # Flag set to True by regrtest.py
 max_memuse = 0           # Disable bigmem tests (they will still be run with
                          # small sizes, to make sure they work.)
 real_max_memuse = 0
@@ -387,9 +388,8 @@
     """
     if resource == 'gui' and not _is_gui_available():
         raise unittest.SkipTest("Cannot use the 'gui' resource")
-    # see if the caller's module is __main__ - if so, treat as if
-    # the resource was set
-    if sys._getframe(1).f_globals.get("__name__") == "__main__":
+    # if we're not running under regrtest, accept anything
+    if not regrtest_run:
         return
     if not is_resource_enabled(resource):
         if msg is None:
diff --git a/Lib/test/test_codecmaps_hk.py b/Lib/test/test_codecmaps_hk.py
--- a/Lib/test/test_codecmaps_hk.py
+++ b/Lib/test/test_codecmaps_hk.py
@@ -17,5 +17,4 @@
     support.run_unittest(__name__)
 
 if __name__ == "__main__":
-    support.use_resources = ['urlfetch']
     test_main()
diff --git a/Lib/test/test_idle.py b/Lib/test/test_idle.py
--- a/Lib/test/test_idle.py
+++ b/Lib/test/test_idle.py
@@ -10,10 +10,5 @@
 load_tests = idletest.load_tests
 
 if __name__ == '__main__':
-    # Until unittest supports resources, we emulate regrtest's -ugui
-    # so loaded tests run the same as if textually present here.
-    # If any Idle test ever needs another resource, add it to the list.
-    from test import support
-    support.use_resources = ['gui']  # use_resources is initially None
     import unittest
     unittest.main(verbosity=2, exit=False)
diff --git a/Lib/test/test_imaplib.py b/Lib/test/test_imaplib.py
--- a/Lib/test/test_imaplib.py
+++ b/Lib/test/test_imaplib.py
@@ -463,5 +463,4 @@
 
 
 if __name__ == "__main__":
-    support.use_resources = ['network']
     unittest.main()
diff --git a/Lib/test/test_robotparser.py b/Lib/test/test_robotparser.py
--- a/Lib/test/test_robotparser.py
+++ b/Lib/test/test_robotparser.py
@@ -290,5 +290,4 @@
     return suite
 
 if __name__=='__main__':
-    support.use_resources = ['network']
     unittest.main()
diff --git a/Lib/test/test_tk.py b/Lib/test/test_tk.py
--- a/Lib/test/test_tk.py
+++ b/Lib/test/test_tk.py
@@ -11,15 +11,9 @@
 
 from tkinter.test import runtktests
 
-def test_main(enable_gui=False):
-    if enable_gui:
-        if support.use_resources is None:
-            support.use_resources = ['gui']
-        elif 'gui' not in support.use_resources:
-            support.use_resources.append('gui')
-
+def test_main():
     support.run_unittest(
             *runtktests.get_tests(text=False, packages=['test_tkinter']))
 
 if __name__ == '__main__':
-    test_main(enable_gui=True)
+    test_main()
diff --git a/Lib/test/test_ttk_guionly.py b/Lib/test/test_ttk_guionly.py
--- a/Lib/test/test_ttk_guionly.py
+++ b/Lib/test/test_ttk_guionly.py
@@ -23,13 +23,7 @@
     # assuming ttk is not available
     raise unittest.SkipTest("ttk not available: %s" % msg)
 
-def test_main(enable_gui=False):
-    if enable_gui:
-        if support.use_resources is None:
-            support.use_resources = ['gui']
-        elif 'gui' not in support.use_resources:
-            support.use_resources.append('gui')
-
+def test_main():
     try:
         support.run_unittest(
                 *runtktests.get_tests(text=False, packages=['test_ttk']))
@@ -37,4 +31,4 @@
         get_tk_root().destroy()
 
 if __name__ == '__main__':
-    test_main(enable_gui=True)
+    test_main()