You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: test_argf.rb
    path of file: ./repos/truffleruby/test/mri/tests/ruby
    
    the code of the file until where you have to start completion: # frozen_string_literal: false
require 'test/unit'
require 'timeout'
require 'tmpdir'
require 'tempfile'
require 'fileutils'

class TestArgf < Test::Unit::Te
    
  def test_inplace_dup
    t = make_tempfile

    assert_in_out_err(["-", t.path], "#{<<~"{#"}\n#{<<~'};'}", [], [])
    {#
      ARGF.inplace_mode = '.bak'
      f = ARGF.dup
      while line = f.gets
        puts line.chomp + '.new'
      end