diff --git a/Rakefile b/Rakefile
new file mode 100644
index 000000000..deb52f2cd
--- /dev/null
+++ b/Rakefile
@@ -0,0 +1,9 @@
+require 'rake/testtask'
+
+Rake::TestTask.new do |t|
+  t.libs = ["lib"]
+  t.warning = true
+  t.test_files = FileList['specs/*_spec.rb']
+end
+
+task default: :test
diff --git a/design-activity.md b/design-activity.md
new file mode 100644
index 000000000..2c9fa900e
--- /dev/null
+++ b/design-activity.md
@@ -0,0 +1,51 @@
+1. What classes does each implementation include? Are the lists the same?
+  answer: Each implementation include three classes: CartEntry, ShoppingCart, Order.
+  in implementation A the total price is calculated only in order class and in implementation B the total price is calculated for each class in separate
+
+2. Write down a sentence to describe each class.
+  answer:
+  Implementation A:
+  class CartEntry: Store the unit price and quantity
+  class ShoppingCart: Store an array of entries
+  class  Order: Store an instant of ShoppingCart and calculate order (price * quantity) after adding Tax
+  Implementation B:
+  class CartEntry: Store the unit price and quantity and calculate (price * quantity)
+  class ShoppingCart: Store an array of entries and calculate prices for all the entries
+  class  Order: Adding Tax for what was already calculate in ShoppingCart class
+
+3. How do the classes relate to each other? It might be helpful to draw a diagram on a whiteboard or   piece of paper.
+answer: class CartEntry store the unit price and quantity, class ShoppingCart store array of entries and class Order store ShoppingCart object and add Tax
+
+4. What data does each class store? How (if at all) does this differ between the two implementations?
+answer:
+Implementation A:
+class CartEntry: Store the unit price and quantity
+class ShoppingCart: Store an array of entries
+class  Order: Store an instant of ShoppingCart and calculate order (price * quantity) after adding Tax
+Implementation B:
+class CartEntry: Store the unit price and quantity and calculate (price * quantity)
+class ShoppingCart: Store an array of entries and calculate prices for all the entries
+class  Order: Adding Tax for what was already calculate in ShoppingCart class
+
+5. What methods does each class have? How (if at all) does this differ between the two implementations?
+  answer:
+  Implementation A:
+  class CartEntry: initialize
+  class ShoppingCart: initialize
+  class  Order: initialize, total_price
+  Implementation B:
+  class CartEntry: initialize, price
+  class ShoppingCart: initialize, price
+  class  Order: initialize, total_price
+
+6. Consider the Order#total_price method. In each implementation:
+  - Is logic to compute the price delegated to "lower level" classes like ShoppingCart and CartEntry, or is it retained in Order?
+  - Does total_price directly manipulate the instance variables of other classes?
+
+7. If we decide items are cheaper if bought in bulk, how would this change the code? Which implementation is easier to modify?
+  answer: We will need to use an if statement and it will be easier to modify implementation A
+
+8. Which implementation better adheres to the single responsibility principle?
+  answer: Implementation B is better
+
+9. Bonus question once you've read Metz ch. 3: Which implementation is more loosely coupled?
diff --git a/lib/management.rb b/lib/management.rb
new file mode 100644
index 000000000..88b93276e
--- /dev/null
+++ b/lib/management.rb
@@ -0,0 +1,37 @@
+module Hotel
+  class Management
+
+    # PRICE_PER_NIGHT = 200
+    attr_reader :rooms, :price_per_night
+
+    def initialize
+      @rooms = []
+      (1..20).each do |num|
+        @rooms << Hotel::Room.new(num)
+      end
+      @reservations = []
+
+    end
+
+    def reserve_room(room, check_in, check_out)
+      reservation = Hotel::Reservation.new(room, check_in, check_out)
+      @reservations << reservation
+      return reservation
+    end
+
+    def get_reservations_for_date(date)
+      reservations_for_date = []
+      @reservations.each do |reservation|
+        if reservation.dates.include?(date) #check_in == date
+          reservations_for_date << reservation
+        end
+      end
+      return reservations_for_date
+    end
+
+
+
+
+
+  end # end of class
+end # end of module
diff --git a/lib/period.rb b/lib/period.rb
new file mode 100644
index 000000000..c109d4801
--- /dev/null
+++ b/lib/period.rb
@@ -0,0 +1,25 @@
+require 'pry'
+module Hotel
+  class Period
+
+    attr_reader :check_in, :check_out
+
+    def initialize(check_in, check_out)
+      @check_in = check_in
+      @check_out = check_out
+    end
+
+    def is_valid?
+      (@check_out != nil && @check_in != nil) && !(@check_out <= @check_in) 
+   end
+
+    def num_of_nights
+      return check_out - check_in
+    end
+
+    def include?(date)
+      return date >= check_in && date < check_out
+    end
+
+  end
+end
diff --git a/lib/reservation.rb b/lib/reservation.rb
new file mode 100644
index 000000000..c0d694f06
--- /dev/null
+++ b/lib/reservation.rb
@@ -0,0 +1,17 @@
+module Hotel
+  class Reservation
+
+    attr_reader :room, :dates, :total_cost
+    def initialize(room, check_in, check_out)
+      @room = room
+      @dates = Hotel::Period.new(check_in, check_out)
+        if !@dates.is_valid? || !@room.is_available(@dates)
+          raise ArgumentError.new("This dates are not availabe")
+        end
+      @room.mark_dates_as_reserved(@dates)
+      @total_cost = @dates.num_of_nights * @room.price_per_night
+    end
+
+
+  end
+end
diff --git a/lib/room.rb b/lib/room.rb
new file mode 100644
index 000000000..df13397a4
--- /dev/null
+++ b/lib/room.rb
@@ -0,0 +1,38 @@
+module Hotel
+  class Room
+
+    PRICE_PER_NIGHT = 200
+    attr_reader :room_num, :price_per_night
+
+    def initialize(num)
+      @room_num = num
+      @price_per_night = PRICE_PER_NIGHT
+      @reserved_dates = []
+    end
+
+
+
+    def mark_dates_as_reserved(reservation_period)
+      (reservation_period.check_in...reservation_period.check_out).each do |date|
+        @reserved_dates << date
+      end
+    end
+
+  	def is_reserved_for_date(date)
+      if date != nil 
+        @reserved_dates.include?(date)
+      else
+        raise ArgumentError.new("Invalid date")
+      end
+    end
+
+    def is_available(query_period)
+      (query_period.check_in...query_period.check_out).each do |date|
+        if is_reserved_for_date(date)
+          return false
+        end
+      end
+      return true
+    end
+  end
+end
diff --git a/specs/management_spec.rb b/specs/management_spec.rb
new file mode 100644
index 000000000..b5c3cb754
--- /dev/null
+++ b/specs/management_spec.rb
@@ -0,0 +1,54 @@
+require_relative 'spec_helper'
+
+describe 'Management class' do
+  describe 'initialize' do
+    it "can be created" do
+      hotel_management = Hotel::Management.new
+      hotel_management.must_be_instance_of Hotel::Management
+      hotel_management.rooms.must_be_kind_of Array
+      reservations = Hotel::Management.new
+      reservations.must_be_instance_of Hotel::Management
+    end
+    it "can access the list of all of the rooms in the hotel" do
+      hotel = Hotel::Management.new
+      hotel.rooms.length.must_equal 20
+    end
+
+    it "there should be 20 total rooms" do
+      hotel = Hotel::Management.new
+      hotel.rooms.count.must_equal 20
+    end
+
+  end
+  describe 'reserve_room' do
+    it 'return reservation' do
+      room = Hotel::Room.new(1)
+      check_in = Date.new(2018, 03, 01)
+      check_out = Date.new(2018, 03, 03)
+      reservation = Hotel::Management.new.reserve_room(room, check_in, check_out)
+      reservation.dates.check_in.must_equal check_in
+      reservation.dates.check_out.must_equal check_out
+    end
+
+    it 'raise an error if room is already reserved' do
+      room = Hotel::Room.new(1)
+      check_in = Date.new(2018, 03, 01)
+      check_out = Date.new(2018, 03, 03)
+      reservation = Hotel::Management.new.reserve_room(room, check_in, check_out)
+      proc{ Hotel::Management.new.reserve_room(room, check_in, check_out)}.must_raise ArgumentError
+    end
+  end
+
+  describe 'get_reservations_for_date' do
+    it 'return an array of reservations for date' do
+      management = Hotel::Management.new
+      room = Hotel::Room.new(1)
+      date = Date.new(2018, 03, 02)
+      check_in = Date.new(2018, 03, 01)
+      check_out = Date.new(2018, 03, 03)
+      management.reserve_room(room, check_in, check_out)
+      management.get_reservations_for_date(date).must_be_kind_of Array
+      management.get_reservations_for_date(date).length.must_equal 1
+    end
+  end
+end
diff --git a/specs/period_spec.rb b/specs/period_spec.rb
new file mode 100644
index 000000000..955a82ccd
--- /dev/null
+++ b/specs/period_spec.rb
@@ -0,0 +1,69 @@
+require_relative 'spec_helper'
+
+describe 'Period class' do
+
+  describe 'initialize' do
+    it 'Can initialize check in and check out' do
+      check_in = Date.new(2018, 03, 01)
+      check_out = Date.new(2017, 03, 03)
+      period = Hotel::Period.new(check_in, check_out)
+      period.check_in.must_equal check_in
+      period.check_out.must_equal check_out
+      period.must_be_instance_of Hotel::Period
+    end
+
+    it "is an instance of Date" do
+      check_in = Date.new(2018, 03, 01)
+      check_out = Date.new(2017, 03, 03)
+      check_in.must_be_kind_of Date
+      check_out.must_be_kind_of Date
+    end
+  end
+
+  describe 'num_of_nights' do
+    it "accurately calculates the number of night" do
+      check_in = Date.new(2018, 03, 16)
+      check_out = Date.new(2018, 03, 19)
+      period = Hotel::Period.new(check_in, check_out)
+      period.num_of_nights.must_equal 3
+    end
+  end
+
+  describe "is_valid?" do
+    it 'cannot have negative number of days' do
+      check_in = Date.new(2018, 03, 01)
+      check_out = Date.new(2018, 02, 25)
+      Hotel::Period.new(check_in, check_out).is_valid?.must_equal false
+    end
+
+    it 'cannot have 0 days' do
+      check_in = Date.new(2018, 03, 01)
+      check_out = Date.new(2018, 03, 01)
+      Hotel::Period.new(check_in, check_out).is_valid?.must_equal false
+    end
+
+    it 'valid dates' do
+      check_in = Date.new(2018, 03, 01)
+      check_out = Date.new(2018, 03, 03)
+      Hotel::Period.new(check_in, check_out).is_valid?.must_equal true
+    end
+  end
+
+  describe 'include?' do
+    it "returns true if the date is between check_in and check_out" do
+      check_in = Date.new(2018, 03, 01)
+      check_out = Date.new(2018, 03, 04)
+      period = Hotel::Period.new(check_in, check_out)
+      date = Date.new(2018, 03, 03)
+      period.include?(date).must_equal true
+    end
+
+    it "returns false if the date is not between check_in and check_out" do
+      check_in = Date.new(2018, 03, 01)
+      check_out = Date.new(2018, 03, 04)
+      period = Hotel::Period.new(check_in, check_out)
+      date = Date.new(2018, 03, 05)
+      period.include?(date).must_equal false
+    end
+  end
+end
diff --git a/specs/reservation_spec.rb b/specs/reservation_spec.rb
new file mode 100644
index 000000000..32150120c
--- /dev/null
+++ b/specs/reservation_spec.rb
@@ -0,0 +1,42 @@
+require_relative 'spec_helper'
+
+describe 'Reservation class' do
+
+  describe 'initialize' do
+    it 'can be created' do
+      room = Hotel::Room.new(1)
+      check_in = Date.new(2018,03,01)
+      check_out = Date.new(2018,03,03)
+      dates = Hotel::Period.new(check_in, check_out)
+      reservation = Hotel::Reservation.new(room, check_in, check_out)
+      room.must_be_instance_of Hotel::Room
+      dates.must_be_instance_of Hotel::Period
+    end
+    it 'can calculate the total cost' do
+      reservation = Hotel::Reservation.new(Hotel::Room.new(1), Date.new(2018,03,01), Date.new(2018,03,03))
+      room = Hotel::Room.new(1)
+      dates = Hotel::Period.new(Date.new(2018,03,01), Date.new(2018,03,03))
+      room.mark_dates_as_reserved(dates)
+      price_per_night = room.price_per_night
+      total_cost = dates.num_of_nights * price_per_night
+      reservation.total_cost.must_equal 400
+    end
+    it 'raise an error if the date range is not availabe' do
+      room = Hotel::Room.new(1)
+      dates = Hotel::Period.new(Date.new(2018,03,01), Date.new(2018,03,03))
+      reservation = Hotel::Reservation.new(room, Date.new(2018,03,01), Date.new(2018,03,03))
+      room.mark_dates_as_reserved(dates)
+      proc{ Hotel::Reservation.new(room, Date.new(2018,03,01), Date.new(2018,03,02))}.must_raise ArgumentError
+
+      # new_dates = Hotel::Period.new(Date.new(2018,03,01), Date.new(2018,03,02))
+    end
+
+    it 'raise an error if the date is in_valid' do
+      room = Hotel::Room.new(1)
+      dates = Hotel::Period.new(Date.new(2018,03,01), Date.new(2018,03,01))
+      reservation = Hotel::Reservation.new(room, Date.new(2018,03,01), Date.new(2018,03,03))
+      room.mark_dates_as_reserved(dates)
+      proc{ Hotel::Reservation.new(room, Date.new(2018,03,01), Date.new(2018,03,02))}.must_raise ArgumentError
+    end
+  end
+end
diff --git a/specs/room_spec.rb b/specs/room_spec.rb
new file mode 100644
index 000000000..679afe6a6
--- /dev/null
+++ b/specs/room_spec.rb
@@ -0,0 +1,68 @@
+require_relative 'spec_helper'
+require 'pry'
+
+describe 'Room class' do
+  describe 'initialize' do
+    it 'can create an instance of a room' do
+      room = Hotel::Room.new(1)
+      room.must_be_instance_of Hotel::Room
+      room.room_num.must_equal 1
+    end
+  end
+
+  describe 'mark_dates_as_reserved' do
+    it 'should not mark the date as reserved' do
+      room = Hotel::Room.new(1)
+      period = Hotel::Period.new(Date.new(2018,03,01), Date.new(2018,03,03))
+      room.mark_dates_as_reserved(period)
+      period2 = Hotel::Period.new(Date.new(2018,03,02), Date.new(2018,03,04))
+      room.is_available(period2).must_equal false
+    end
+    it 'it should mark the date as reserved' do
+      room = Hotel::Room.new(1)
+      period = Hotel::Period.new(Date.new(2018,03,01), Date.new(2018,03,03))
+      room.mark_dates_as_reserved(period)
+      period2 = Hotel::Period.new(Date.new(2018,03,03), Date.new(2018,03,05))
+      room.is_available(period2).must_equal true
+    end
+  end
+
+  describe 'is_reserved_for_date' do
+    it 'raise an error if the date is nil' do
+      room = Hotel::Room.new(1)
+      date = nil
+      proc {room.is_reserved_for_date(date)}.must_raise ArgumentError
+    end
+    it 'should return false if the date is include in the array' do
+      room = Hotel::Room.new(1)
+      period = Hotel::Period.new(Date.new(2018,03,01), Date.new(2018,03,03))
+      room.mark_dates_as_reserved(period)
+      date = Date.new(2018,02,02)
+      room.is_reserved_for_date(date).must_equal false
+    end
+    it 'should return true if the date is include in the array' do
+      room = Hotel::Room.new(1)
+      period = Hotel::Period.new(Date.new(2018,03,01), Date.new(2018,03,03))
+      room.mark_dates_as_reserved(period)
+      date = Date.new(2018,03,02)
+      room.is_reserved_for_date(date).must_equal true
+    end
+  end
+
+  describe 'is_available' do
+    it 'return true if the range of dates are available' do
+      room = Hotel::Room.new(1)
+      period = Hotel::Period.new(Date.new(2018,03,01), Date.new(2018,03,03))
+      room.mark_dates_as_reserved(period)
+      period2 = Hotel::Period.new(Date.new(2018,03,03), Date.new(2018,03,05))
+      room.is_available(period2).must_equal true
+    end
+    it 'return false if the range of dates are not available' do
+      room = Hotel::Room.new(1)
+      period = Hotel::Period.new(Date.new(2018,03,01), Date.new(2018,03,03))
+      room.mark_dates_as_reserved(period)
+      period2 = Hotel::Period.new(Date.new(2018,03,02), Date.new(2018,03,05))
+      room.is_available(period2).must_equal false
+    end
+  end
+end
diff --git a/specs/spec_helper.rb b/specs/spec_helper.rb
new file mode 100644
index 000000000..0a20f5a8c
--- /dev/null
+++ b/specs/spec_helper.rb
@@ -0,0 +1,18 @@
+require 'simplecov'
+SimpleCov.start do
+  add_filter "/specs/"
+end
+
+require 'minitest'
+require 'minitest/autorun'
+require 'minitest/reporters'
+require 'awesome_print'
+require 'date'
+# Add simplecov
+
+Minitest::Reporters.use! Minitest::Reporters::SpecReporter.new
+
+require_relative '../lib/room'
+require_relative '../lib/reservation'
+require_relative '../lib/period'
+require_relative '../lib/management'