test-overload-equality.rb

require 'rubygems'
require 'test/unit'

class Agent
  
  attr_accessor :list
  
  def initialize (list=[])
    self.list = list
  end
  
  def ==(other)
    raise ArgumentError unless other.is_a? Agent
    true if other.list.eql?(list)
  end
    
end

class TestAgent < Test::Unit::TestCase
  
  def setup
    @red   = Agent.new([1,2,3])
    @blue  = Agent.new([1,2,3])
    @green = Agent.new([:a,:b,:c])
  end

  def test_equal
    assert_equal(@red, @blue)
  end
  
  def test_not_equal
    assert_not_equal(@red, @green)
  end
end