jumpstartlab objects-and-methods exercise

README.md

Note from Viki: working on exercise 2. I'm on bag.rb. Tests were provided, I'm running bag_test.rb and running into issues on line 90, which is testing my method take in bag.rb starting on line 34.

Objects and Methods

Exercise 1

If you'd like to be walked through the exercise, check out the Objects and Methods workshop on the Jumpstart Lab tutorials site.

Make the tests pass in the following sequence:

• test/candy_test.rb
• test/bag_test.rb
• test/costume_test.rb
• test/trick_or_treater_test.rb

Run a test file by calling it with ruby:

$ ruby test/bag_test.rb

Exercise 2

Each object has become a little bit more complex.

Make the tests pass in the following sequence:

• test/candy_test.rb
• test/bag_test.rb
• test/costume_test.rb
• test/trick_or_treater_test.rb

bag.rb

class Bag

  def initialize
    @candies = []
  end

  def candies
    @candies
  end

  def empty?
    candies.count == 0
  end

  def count
    candies.count
  end

  def <<(candy)
    candies << candy
  end

  def contains?(type)
    candies.any? do |candy|
      candy.type == type
    end
  end

  def grab(piece)
    candy_piece = candies.find { |candy| candy.type == piece}
    candies.delete(candy_piece)
  end

  def take(number)
    removed_candies = candies.take(number)
    removed_candies.each { |candy| candies.delete(candy)}
  end
end

bag_test.rb

gem 'minitest', '~> 5.2'
require 'minitest/autorun'
require 'minitest/pride'
require_relative '../lib/bag'
require_relative '../lib/candy'

class BagTest < Minitest::Test
  def test_a_new_bag_is_empty
    assert Bag.new.empty?
  end

  def test_count_the_candies_in_an_empty_bag
    assert_equal 0, Bag.new.count
  end

  def test_empty_bag_has_no_candies
    assert_equal [], Bag.new.candies
  end

  def test_put_candy_in_the_bag
    bag = Bag.new
    candy = Candy.new("Sour frogs")
    bag << candy
    assert_equal [candy], bag.candies
  end

  def test_a_bag_with_candies_is_not_empty
    bag = Bag.new
    bag << Candy.new("Nerds")
    refute bag.empty?
  end

  def test_bag_counts_candies
    bag = Bag.new
    bag << Candy.new("Caramelized Almonds")
    assert_equal 1, bag.count
  end

  def test_bag_contains_candies_and_candies_have_a_type
    bag = Bag.new
    bag << Candy.new("Hershey's Kisses")
    # You usually don't want to chain a bunch of different
    # types of things together like this.
    # We'll talk about it more in a few weeks.
    # It's important to understand how these methods work, though.
    type = bag.candies.first.type
    assert_equal "Hershey's Kisses", type
  end

  def test_ask_bag_if_it_contains_a_particular_type_of_candy
    bag = Bag.new
    bag << Candy.new("Lindt chocolate")

    assert bag.contains?("Lindt chocolate")
    refute bag.contains?("Hershey's chocolate")
  end

  def test_get_a_particular_type_of_candy
    bag = Bag.new
    bag << Candy.new("Jawbreaker")
    bag << Candy.new("Jawbreaker")
    bag << Candy.new("Jolly Ranchers")
    bag << Candy.new("100 Grand")

    candy = bag.grab "Jawbreaker"
    assert_equal "Jawbreaker", candy.type
  end

  def test_grabbing_candy_removes_it_from_the_bag
    bag = Bag.new
    bag << Candy.new("Reese's Pieces")
    bag << Candy.new("Junior Mints")
    bag << Candy.new("Reese's Pieces")
    assert_equal 3, bag.count

    candy = bag.grab "Reese's Pieces"
    assert_equal 2, bag.count
  end

  def test_take_a_number_of_candies_from_the_bag
    bag = Bag.new
    bag << Candy.new("Swedish Fish")
    bag << Candy.new("Milky Way")
    bag << Candy.new("Cotton Candy")

    assert_equal 3, bag.count

    taken = bag.take(2)
    assert_equal 2, taken.size
    assert_equal 1, bag.count
  end

  def test_take_one_candy
    bag = Bag.new
    bag << Candy.new("Lifesavers")

    candy = bag.take(1)
    assert_equal "Lifesavers", candy.type
  end
end

candy.rb

class Candy

  def initialize(candy, sugar=100)
    @candy = candy
    @sugar = sugar
  end

  def type
    @candy
  end

  def sugar
    @sugar
  end

end

candy_test.rb

gem 'minitest', '~> 5.2'
require 'minitest/autorun'
require 'minitest/pride'
require_relative '../lib/candy'

class CandyTest < Minitest::Test
  def test_candy_type
    candy = Candy.new("Skittles")
    assert_equal "Skittles", candy.type
  end

  def test_other_type_of_candy
    candy = Candy.new("Mars")
    assert_equal "Mars", candy.type
  end

  def test_amount_of_sugar_is_100_by_default
    candy = Candy.new("Circus Peanuts")
    assert_equal 100, candy.sugar
  end

  def test_amount_of_sugar_is_configurable
    candy = Candy.new("Pop Rocks", 78)
    assert_equal 78, candy.sugar
  end
end