With Cocoa Tk 8.5.15 or Cocoa Tk 8.6.1 on OS X 10.8.5, test_widgets.ButtonTest crashes Tk:

test_image (tkinter.test.test_tkinter.test_widgets.ButtonTest) ... 2013-11-03 01:52:53.498 pytest_10.8[82465:f07] *** Assertion failure in -[NSBitmapImageRep initWithCGImage:], /SourceCache/AppKit/AppKit-1187.40/AppKit.subproj/NSBitmapImageRep.m:1242
2013-11-03 01:52:53.499 pytest_10.8[82465:f07] An uncaught exception was raised
2013-11-03 01:52:53.499 pytest_10.8[82465:f07] Invalid parameter not satisfying: cgImage != NULL
2013-11-03 01:52:53.502 pytest_10.8[82465:f07] (
	0   CoreFoundation                      0x965eae8b __raiseError + 219
	1   libobjc.A.dylib                     0x956d152e objc_exception_throw + 230
	2   CoreFoundation                      0x9654a698 +[NSException raise:format:arguments:] + 136
	3   Foundation                          0x966a5364 -[NSAssertionHandler handleFailureInMethod:object:file:lineNumber:description:] + 116
	4   AppKit                              0x98a34525 -[NSBitmapImageRep initWithCGImage:] + 145
	5   Tk                                  0x00725a48 CreateNSImageWithPixmap + 151
	6   Tk                                  0x00725b1c TkMacOSXGetNSImageWithTkImage + 149
	7   Tk                                  0x0071eb2f TkpComputeButtonGeometry + 2550
	8   Tk                                  0x0069849d TkButtonWorldChanged + 470
	9   Tk                                  0x00698e99 ConfigureButton + 1981
	10  Tk                                  0x0069980f ButtonWidgetObjCmd + 440
	11  Tcl                                 0x00579c2f TclEvalObjvInternal + 770
	12  Tcl                                 0x0057ac1a Tcl_EvalObjv + 72
	13  _tkinter.so                         0x0055db81 Tkapp_Call + 673
        [...]


With Carbon Tk 8.4.20 on OS X 10.8.5, two test_insertborderwidth failures:

======================================================================
FAIL: test_insertborderwidth (tkinter.test.test_tkinter.test_widgets.EntryTest)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/py/dev/3x/root/fwd32/Library/Frameworks/pytest_10.8.framework/Versions/3.4/lib/python3.4/tkinter/test/test_tkinter/test_widgets.py", line 327, in test_insertborderwidth
    self.checkPixelsParam(widget, 'insertborderwidth', 0, 1.3, -2)
  File "/py/dev/3x/root/fwd32/Library/Frameworks/pytest_10.8.framework/Versions/3.4/lib/python3.4/tkinter/test/widget_tests.py", line 158, in checkPixelsParam
    conv=conv1, **kwargs)
  File "/py/dev/3x/root/fwd32/Library/Frameworks/pytest_10.8.framework/Versions/3.4/lib/python3.4/tkinter/test/widget_tests.py", line 48, in checkParam
    self.assertEqual2(widget[name], expected, eq=eq)
  File "/py/dev/3x/root/fwd32/Library/Frameworks/pytest_10.8.framework/Versions/3.4/lib/python3.4/tkinter/test/widget_tests.py", line 32, in assertEqual2
    self.assertEqual(actual, expected, msg)
AssertionError: 0 != 1

======================================================================
FAIL: test_insertborderwidth (tkinter.test.test_tkinter.test_widgets.SpinboxTest)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/py/dev/3x/root/fwd32/Library/Frameworks/pytest_10.8.framework/Versions/3.4/lib/python3.4/tkinter/test/test_tkinter/test_widgets.py", line 327, in test_insertborderwidth
    self.checkPixelsParam(widget, 'insertborderwidth', 0, 1.3, -2)
  File "/py/dev/3x/root/fwd32/Library/Frameworks/pytest_10.8.framework/Versions/3.4/lib/python3.4/tkinter/test/widget_tests.py", line 158, in checkPixelsParam
    conv=conv1, **kwargs)
  File "/py/dev/3x/root/fwd32/Library/Frameworks/pytest_10.8.framework/Versions/3.4/lib/python3.4/tkinter/test/widget_tests.py", line 48, in checkParam
    self.assertEqual2(widget[name], expected, eq=eq)
  File "/py/dev/3x/root/fwd32/Library/Frameworks/pytest_10.8.framework/Versions/3.4/lib/python3.4/tkinter/test/widget_tests.py", line 32, in assertEqual2
    self.assertEqual(actual, expected, msg)
AssertionError: 0 != 1

----------------------------------------------------------------------
Ran 536 tests in 1.149s

FAILED (failures=2, skipped=10)