about_dice_project.rb

require File.expand_path(File.dirname(__FILE__) + "/neo")

# TIL:
# - When expecting a random number(s) not to match e.g. in a unit test, it's best to also check object id in the rare
#   case that a random number(s) is selected more than once.

# Implement a DiceSet Class here:
class DiceSet
  attr_accessor :values

  def initialize
    @values = []
  end

  def roll(number)
    self.values = []
    number.times { values << rand(1..6) }

    values
  end
end

class AboutDiceProject < Neo::Koan
  def test_can_create_a_dice_set
    dice = DiceSet.new
    assert_not_nil dice
  end

  def test_rolling_the_dice_returns_a_set_of_integers_between_1_and_6
    dice = DiceSet.new

    dice.roll(5)
    assert dice.values.is_a?(Array), "should be an array"
    assert_equal 5, dice.values.size
    dice.values.each do |value|
      assert value >= 1 && value <= 6, "value #{value} must be between 1 and 6"
    end
  end

  def test_dice_values_do_not_change_unless_explicitly_rolled
    dice = DiceSet.new
    dice.roll(5)
    first_time = dice.values
    second_time = dice.values
    assert_equal first_time, second_time
  end

  # THINK ABOUT IT:
  #
  # If the rolls are random, then it is possible (although not
  # likely) that two consecutive rolls are equal.  What would be a
  # better way to test this?

  # Answer found here: http://stackoverflow.com/questions/2082970/whats-the-best-way-to-test-this

  def test_dice_values_should_change_between_rolls
    dice = DiceSet.new

    dice.roll(5)
    first_time = dice.values

    dice.roll(5)
    second_time = dice.values

    assert_not_equal [first_time, first_time.object_id],
      [second_time, second_time.object_id], "Two rolls should not be equal"
  end

  def test_you_can_roll_different_numbers_of_dice
    dice = DiceSet.new

    dice.roll(3)
    assert_equal 3, dice.values.size

    dice.roll(1)
    assert_equal 1, dice.values.size
  end
end