end
function test_zzz_undo_load_test()
  print('\n\nTesting a 10KB file')
  -- create a large list of lines
  local lines = {}
  -- 10k characters, hundred lines, 2k words
  for i=1,100 do
    local line = ''
    for c=1,20 do
      line = line..'abcd '
    end
  end
  Lines = load_array(lines)
  -- perform 1000 mutations
  print('are the dots printing quickly and without any pauses?')
  for i=1,1000 do
    if i%50 == 0 then
      App.run_after_keychord('return')
    else
      App.run_after_textinput('a')
    end
    if i%10 == 0 then
      io.write(i)
      io.write(' ')
      io.flush()
    end
  end