wtf.rb

class WTF
  attr_reader :color
  
  def initialize
    @color = 'red'
  end
  
  def color_with_self
    color = self.color
    color
  end
  
  def color_without_self
    color = color
    color
  end
end

require "test/unit"

class WTFTest < Test::Unit::TestCase
  def test_with_self
    assert_equal "red", WTF.new.color_with_self
  end

  def test_without_self
    assert_equal "red", WTF.new.color_without_self
  end
end