[ruby] parse_bool.rb

parse_bool.rb

# encoding: utf-8

# 論理値に変換する
#
# falseとなる値
#   nil, false, 0
# falseとなる文字列(大文字小文字区別なし)
#   0, 0.0, f, false, n, no, off, 空文字, 空白文字のみ
# trueとなるもの
#   上記以外
#
# @param [Object] value 評価する値
# @return [Boolean]
def parse_bool(value)
  case value
  when nil, false, 0
    return false
  end

  str = value.to_s.strip
  return false if str.empty? || /\A(?:0+|0*\.0+|f|false|n|no|off)\z/i =~ str

  true
end

parse_boole_test.rb

# encoding: utf-8

require "minitest/autorun"
require_relative "parse_bool"

# test for parse_bool method.
class TestParseBool < MiniTest::Test
  params = {
    'nil'       => [false, nil],
    'false'     => [false, false],
    '0'         => [false, 0],
    '""'        => [false, ""],
    '"   "'     => [false, "   "],
    '" \t "'    => [false, " \t "],
    '"false"'   => [false, "false"],
    '"FALSE"'   => [false, "FALSE"],
    '"FaLsE"'   => [false, "FaLsE"],
    '"f"'       => [false, "f"],
    '"n"'       => [false, "n"],
    '"no"'      => [false, "no"],
    '"off"'     => [false, "off"],
    '"0"'       => [false, "0"],
    '"000"'     => [false, "000"],
    '"0.0"'     => [false, "0.0"],
    '"000.000"' => [false, "000.000"],
    '".0"'      => [false, ".0"],

    'true'      => [true, true],
    '1'         => [true, 1],
    '999'       => [true, 999],
    '"true"'    => [true, "true"],
    '"TRUE"'    => [true, "TRUE"],
    '"TrUe"'    => [true, "TrUe"],
    '"t"'       => [true, "t"],
    '"yes"'     => [true, "yes"],
    '"y"'       => [true, "y"],
    '"on"'      => [true, "on"],
    '"1"'       => [true, "1"],
    '"0.1"'     => [true, "0.1"],
    '"a"'       => [true, "a"],
    '"+"'       => [true, "+"],
    '"nil"'     => [true, "nil"],
    'object'    => [true, Object.new],
  }

  params.each do |name, (expected, target)|
    define_method("test_#{name}") do
      assert_equal(expected, parse_bool(target))
    end
  end
end