def handle_missing_or_unknown_args
      if first_arg_not_a_flag_or_file?
        exit_with_unknown_command
      elsif has_output_flag? || has_format_flag?
        check_for_output_file if has_output_flag?
        check_for_format_type if has_format_flag?
      elsif only_has_flag_arguments?
        add_test_command
      else
        exit_with_cannot_understand
      end
    end
def handle_missing_or_unknown_args
      if first_arg_not_a_flag_or_file?
        exit_with_unknown_command
      elsif has_output_flag? || has_format_flag?
        check_for_output_file if has_output_flag?
        check_for_format_type if has_format_flag?
      elsif only_has_flag_arguments?
        add_test_command
      else
        exit_with_cannot_understand
      end
    end
Arg manipulation methods