bpo-42749: Use dynamic version to test for unsupported bignum in Tk (GH-23966)

Tk can internally support bignum even if Tkinter is built without
support of bignum.
(cherry picked from commit 156b7f7052102ee1633a18e9a136ad8c38f66db0)

Co-authored-by: Serhiy Storchaka <storchaka@gmail.com>

diff --git a/Lib/test/test_tcl.py b/Lib/test/test_tcl.py
index a126b68a108fafb95b8d60aae78e7bd185e234da..0bbb39b147ea1e543afec9cb29dbd2bab97a0dd9 100644 (file)
--- a/Lib/test/test_tcl.py
+++ b/Lib/test/test_tcl.py
@@ -447,7 +447,7 @@ class TclTest(unittest.TestCase):
             else:
                 self.assertEqual(result, str(i))
                 self.assertIsInstance(result, str)
-        if tcl_version < (8, 5):  # bignum was added in Tcl 8.5
+        if get_tk_patchlevel() < (8, 5):  # bignum was added in Tcl 8.5
             self.assertRaises(TclError, tcl.call, 'expr', str(2**1000))
 
     def test_passing_values(self):