code: def test_bad_encoding(self):
      p = os.path
      fn = p.abspath(p.join(p.dirname(__file__), "..", "CREDITS.txt"))
      view = tv.view_file(root, "Title", fn, "ascii", modal=False)
      self.assertIsNone(view)
      self.assertEqual(tv.showerror.title, "Unicode Decode Error")
  
imports: from idlelib import textview
  from test.support import requires
  import os
  import unittest
  from tkinter import Tk, TclError, CHAR, NONE, WORD
  from tkinter.ttk import Button
  from idlelib.idle_test.mock_idle import Func
  from idlelib.idle_test.mock_tk import Mbox_func
label_desc: Use image node_id 6 for calling the ViewFunctionTest obj's underlying member method code with example usage: obj.test_bad_encoding() without return types