Tests that are failing on my computer:

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FAIL: test_command (tkinter.test.test_ttk.test_widgets.SpinboxTest)
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Traceback (most recent call last):
  File "/home/serhiy/py/cpython/Lib/tkinter/test/test_ttk/test_widgets.py", line 1145, in test_command
    self.assertTrue(success)
AssertionError: [] is not true

======================================================================
FAIL: test_format (tkinter.test.test_ttk.test_widgets.SpinboxTest)
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Traceback (most recent call last):
  File "/home/serhiy/py/cpython/Lib/tkinter/test/test_ttk/test_widgets.py", line 1199, in test_format
    self.assertEqual(len(value), 10)
AssertionError: 1 != 10

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FAIL: test_increment (tkinter.test.test_ttk.test_widgets.SpinboxTest)
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Traceback (most recent call last):
  File "/home/serhiy/py/cpython/Lib/tkinter/test/test_ttk/test_widgets.py", line 1186, in test_increment
    self.assertEqual(self.spin.get(), '5')
AssertionError: '1' != '5'
- 1
+ 5


======================================================================
FAIL: test_to (tkinter.test.test_ttk.test_widgets.SpinboxTest)
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Traceback (most recent call last):
  File "/home/serhiy/py/cpython/Lib/tkinter/test/test_ttk/test_widgets.py", line 1163, in test_to
    self.assertEqual(self.spin.get(), '5')
AssertionError: '4' != '5'
- 4
+ 5


======================================================================
FAIL: test_values (tkinter.test.test_ttk.test_widgets.SpinboxTest)
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Traceback (most recent call last):
  File "/home/serhiy/py/cpython/Lib/tkinter/test/test_ttk/test_widgets.py", line 1248, in test_values
    self.assertEqual(self.spin.get(), '1')
AssertionError: 'a' != '1'
- a
+ 1


======================================================================
FAIL: test_wrap (tkinter.test.test_ttk.test_widgets.SpinboxTest)
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Traceback (most recent call last):
  File "/home/serhiy/py/cpython/Lib/tkinter/test/test_ttk/test_widgets.py", line 1220, in test_wrap
    self.assertEqual(self.spin.get(), '1')
AssertionError: '10' != '1'
- 10
?  -
+ 1


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This may be a race condition depended on window manager or speed of CPU or GPU.