class_docstr: Test setupApp.
code: 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
  
imports: from idlelib import macosx
  import unittest
  from test.support import requires
  import tkinter
  import unittest.mock
  from idlelib.filelist import FileList
label_desc: Use image node_id 1 for calling the SetupTest obj's underlying member method code with example usage: obj.setUpClass(cls) without return types