I have tried this on several debian unstable releases, and get the following 3 failures

lac at smartwheels:~$ lsb_release -a
 LSB Version:	core-2.0-amd64:core-2.0-noarch:core-3.0-amd64:core-3.0-noarch:core-3.1-amd64:core-3.1-noarch:core-3.2-amd64:core-3.2-noarch:core-4.0-amd64:core-4.0-noarch:core-4.1-amd64:core-4.1-noarch:security-4.0-amd64:security-4.0-noarch:security-4.1-amd64:security-4.1-noarch
 Distributor ID:	Debian
 Description:		Debian GNU/Linux unstable (sid)
 Release:		unstable
 Codename:		sid

Idle shows my tk version as 8.6.4
python3 -m test -ugui -v test_tk gives 3 failures

= CPython 3.4.3+ (default, Jul 28 2015, 13:17:50) [GCC 4.9.3]
==   Linux-3.16.0-4-amd64-x86_64-with-debian-stretch-sid little-endian
==   hash algorithm: siphash24 64bit
==   /tmp/test_python_7974
Testing with flags: sys.flags(debug=0, inspect=0, interactive=0, optimize=0, dont_write_bytecode=0, no_user_site=0, no_site=0, ignore_environment=0, verbose=0, bytes_warning=0, quiet=0, hash_randomization=1, isolated=0)

test_default (tkinter.test.test_tkinter.test_variables.TestBooleanVar) ... FAIL
test_get (tkinter.test.test_tkinter.test_variables.TestBooleanVar) ... FAIL
test_set (tkinter.test.test_tkinter.test_variables.TestBooleanVar) ... FAIL

======================================================================
FAIL: test_default (tkinter.test.test_tkinter.test_variables.TestBooleanVar)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/usr/lib/python3.4/tkinter/test/test_tkinter/test_variables.py", line 163, in test_default
      self.assertIs(v.get(), False)
      AssertionError: 0 is not False

======================================================================
FAIL: test_get (tkinter.test.test_tkinter.test_variables.TestBooleanVar)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/usr/lib/python3.4/tkinter/test/test_tkinter/test_variables.py", line 167, in test_get
      self.assertIs(v.get(), True)
      AssertionError: 1 is not True

======================================================================
FAIL: test_set (tkinter.test.test_tkinter.test_variables.TestBooleanVar)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/usr/lib/python3.4/tkinter/test/test_tkinter/test_variables.py", line 186, in test_set
      self.assertEqual(self.root.globalgetvar("name"), true)
      AssertionError: 42 != 1

----------------------------------------------------------------------
Ran 660 tests in 3.901s

FAILED (failures=3)
1 test failed:
    test_tk