assert_equal

今回の題材はテスト駆動用の根幹となる, assert_equalです.まずは1==1から始めてみます.

code

p 1==1

結果

> ruby assert_equal.rb
true

これをテスト用のメソッドに置き換えると,

def assert_equal(expected, result)
  return expected == result
end

p assert_equal(1, 1)

Colorize

require 'colorize'

def assert_equal(expected, result)
  if expected == result
    puts 'true'.green
  else
    puts 'false'.red
  end
end

assert_equal(1, 1)
assert_equal(1, 2)

出力結果が, 緑や赤に変化した.

Richer output

出力をもう少し見やすくする.

require 'colorize'

def assert_equal(expected, result)
  puts "expected :: #{expected}"
  puts "result   :: #{result}"
  if expected == result
    puts "succeeded in assert_equal".green
  else
    puts 'failed in assert_equal'.red
  end
end

assert_equal(1,1)
assert_equal(1,2)

clear code

重複している箇所を個別に分けて関数に書き換える.

require 'colorize'

def puts_vals(expected, result)
  puts "expected :: #{expected}"
  puts "result   :: #{result}"
end

def assert_equal(expected, result)
  puts_vals(expected,result)
  if expected == result
    puts "succeeded in assert_equal".green
  else
    puts 'failed in assert_equal'.red
  end
end

重複実行の予防

require './assert_equal'

assert_equal(2, 1*2)
assert_not_equal('bob', 'bob2')

しかし, 今のままだとassert_equal.rbに書いたテストがそのまま実行されてしまう.それを回避してくれる便利な熟語があるらしい.

if $PROGRAM_NAME == __FILE__
  assert_equal(1, 1)
  assert_equal(1, 2)
  assert_not_equal(1, 2)
  assert_not_equal(1, 1)
end

これを踏まえて, まとめると以下のようになる.以下の内容は覚えておく!!

require 'colorize'
def puts_vals(expected, result)
  puts "expected :: #{expected}"
  puts "result   :: #{result}"
end
def assert_not_equal(expected, result)
  puts_vals(expected, result)
  print expected != result ?
  "succeeded in #{__method__}.\n".green :
    "failed in #{__method__}.\n".red
end
def assert_equal(expected, result)
  puts_vals(expected, result)
  print  case expected == result
     when true  ; "succeeded in #{__method__}.\n".green
     when false ; "failed in #{__method__}.\n".red
     end
end

if $PROGRAM_NAME == __FILE__
  assert_equal(1, 1)
  assert_equal(1, 2)
  assert_not_equal(1, 2)
  assert_not_equal(1, 1)
end

参考サイト

https://qiita.com/daddygongon/items/f6cea87314ee26e130ea https://qiita.com/Mutakouki7595/items/1f3e59fad4aa187a7431

source ~/my_ruby/grad_members_20f/members/drop-sd/lectures/no9.org

第九回講義メモ