# File test_format.rb, line 584
  def helper_test_thirteen (body_fmt, file_name)
    one = "FIVE SIX"
    val1 = one.clone
    two = "ONE TWO"
    val2 = two.clone
    val3 = "Yay"
    var_exp = 3.44e10

    File.open(file_name, 
              File::CREAT | File::WRONLY | File::TRUNC) { |file|
      body_fmt.io = file
      body_fmt.printFormat(binding) 
    }

    #save the output for later
    output = []
    File.open( file_name ){ |file|
      output = file.readlines()
    }
    
    reader = FormatReader.new(body_fmt)
    res = reader.readFormat(output)
    #since we're keying on just @ we can't tell class without the binding
    assert(res['val1'] == one)
    assert(res['val2'] == two)
    assert(res['val3'] == val3)
    assert(res['var_exp'] == var_exp)
    puts "tested 13 in #{file_name}"
    File.delete(file_name) unless (@@keep)
  end