code: def test_bad_file(self):
      # Mock showerror will be used; view_file will return None.
      view = tv.view_file(
          root, "Title", "abc.xyz", "ascii", modal=False
      )
      self.assertIsNone(view)
      self.assertEqual(tv.showerror.title, "File Load 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 5 for calling the ViewFunctionTest obj's underlying member method code with example usage: obj.test_bad_file() without return types