[3.6]bpo-30642: Fix ref leak in idle_test.test_macosx (#2163) (#2165)

terryjreedy · web-flow · commit b0efd493b6af · 2017-06-13T11:52:08.000-04:00
(cherry picked from commit 8323189)
diff --git a/Lib/idlelib/idle_test/test_macosx.py b/Lib/idlelib/idle_test/test_macosx.py
@@ -77,6 +77,10 @@ def setUpClass(cls):
         requires('gui')
         cls.root = tk.Tk()
         cls.root.withdraw()
+        def cmd(tkpath, func):
+            assert isinstance(tkpath, str)
+            assert isinstance(func, type(cmd))
+        cls.root.createcommand = cmd
 
     @classmethod
     def tearDownClass(cls):
