about_dice_project.rb

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

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

  def initialize
    self.values ||= []
  end

  # roll(x) takes in the number of dice to be rolled,
  # and assigns a random value (from 1 - 6) to each die.

  def roll(number_of_dice)
    @values = (1..number_of_dice).map { rand(6) + 1 }

    # Discovered the above shorter and cleaner way on GitHub.
    # number_of_dice.times.each do
    #   self.values << 1 + rand(6)
    # end
    # self.values
  end

  # NOTE: An @ before a value is an instance variable.
  # "values" is the instance variable, and an array when being computed upon
  # by the roll method.
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

  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, second_time,
      "Two rolls should not be equal"

    # 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?
  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