diff -r 5cae52417b9d Lib/test/support.py
--- a/Lib/test/support.py	Thu Jun 30 20:04:06 2011 +0200
+++ b/Lib/test/support.py	Thu Jun 30 18:43:53 2011 -0400
@@ -49,7 +49,8 @@
     "threading_cleanup", "reap_children", "cpython_only", "check_impl_detail",
     "get_attribute", "swap_item", "swap_attr", "requires_IEEE_754",
     "TestHandler", "Matcher", "can_symlink", "skip_unless_symlink",
-    "import_fresh_module", "requires_zlib", "PIPE_MAX_SIZE"
+    "import_fresh_module", "requires_zlib", "PIPE_MAX_SIZE",
+    "requires_tkinter",
     ]

 class Error(Exception):
@@ -471,6 +472,16 @@

 requires_zlib = unittest.skipUnless(zlib, 'requires zlib')

+def requires_tkinter(gui=False):
+    # Skip test if _tkinter wasn't built.
+    import_module('_tkinter')
+    if gui \
+    and sys.platform == 'darwin' \
+    and 'DISPLAY' not in os.environ:
+        raise unittest.SkipTest(
+            "DISPLAY environment variable is required "
+            "to run Tkinter GUI tests")
+
 is_jython = sys.platform.startswith('java')

 # Filename used for testing
diff -r 5cae52417b9d Lib/test/test_tcl.py
--- a/Lib/test/test_tcl.py	Thu Jun 30 20:04:06 2011 +0200
+++ b/Lib/test/test_tcl.py	Thu Jun 30 18:43:53 2011 -0400
@@ -5,18 +5,17 @@
 import os
 from test import support

-# Skip this test if the _tkinter module wasn't built.
-_tkinter = support.import_module('_tkinter')
+support.requires_tkinter()

 from tkinter import Tcl
-from _tkinter import TclError
+from _tkinter import TclError, _flatten


 class TkinterTest(unittest.TestCase):

     def testFlattenLen(self):
         # flatten(<object with no length>)
-        self.assertRaises(TypeError, _tkinter._flatten, True)
+        self.assertRaises(TypeError, _flatten, True)


 class TclTest(unittest.TestCase):
diff -r 5cae52417b9d Lib/test/test_tk.py
--- a/Lib/test/test_tk.py	Thu Jun 30 20:04:06 2011 +0200
+++ b/Lib/test/test_tk.py	Thu Jun 30 18:43:53 2011 -0400
@@ -1,6 +1,5 @@
 from test import support
-# Skip test if _tkinter wasn't built.
-support.import_module('_tkinter')
+support.requires_tkinter(gui=True)

 import tkinter
 from tkinter.test import runtktests
diff -r 5cae52417b9d Lib/test/test_ttk_guionly.py
--- a/Lib/test/test_ttk_guionly.py	Thu Jun 30 20:04:06 2011 +0200
+++ b/Lib/test/test_ttk_guionly.py	Thu Jun 30 18:43:53 2011 -0400
@@ -2,8 +2,7 @@
 import unittest
 from test import support

-# Skip this test if _tkinter wasn't built.
-support.import_module('_tkinter')
+support.requires_tkinter(gui=True)

 from _tkinter import TclError
 from tkinter import ttk
diff -r 5cae52417b9d Lib/test/test_ttk_textonly.py
--- a/Lib/test/test_ttk_textonly.py	Thu Jun 30 20:04:06 2011 +0200
+++ b/Lib/test/test_ttk_textonly.py	Thu Jun 30 18:43:53 2011 -0400
@@ -1,8 +1,7 @@
 import os
 from test import support

-# Skip this test if _tkinter does not exist.
-support.import_module('_tkinter')
+support.requires_tkinter()

 from tkinter.test import runtktests