pony.rb

class Pony
  attr_accessor :hungry

  def initialize
    @hungry = true
  end

  def legs
    4
  end

  def head
    1
  end

  def hungry?
    hungry
  end

  def eats
    @hungry = false
  end
end

pony_test.rb

require './pony'
require 'minitest/autorun'
require 'minitest/pride'

class PonyTest < Minitest::Test
  def test_it_has_four_legs
    pony = Pony.new
    assert_equal 4, pony.legs
  end

  def test_it_has_one_head
    pony = Pony.new
    assert_equal 1, pony.head
  end

  def test_it_is_hungry_when_it_is_born
    pony = Pony.new
    assert_equal true, pony.hungry?
  end

  def test_it_can_eat
    pony = Pony.new
    assert_respond_to(pony, :eats)
  end

  def test_it_is_no_longer_hungry_when_he_eats
    pony = Pony.new
    assert_equal true, pony.hungry?

    pony.eats
    assert_equal false, pony.hungry?
  end
end