diff --git a/.DS_Store b/.DS_Store
new file mode 100644
index 000000000..49ed81a4b
Binary files /dev/null and b/.DS_Store differ
diff --git a/.gitignore b/.gitignore
index 5e1422c9c..c0ac3dc53 100644
--- a/.gitignore
+++ b/.gitignore
@@ -48,3 +48,4 @@ build-iPhoneSimulator/
 
 # unless supporting rvm < 1.11.0 or doing something fancy, ignore this:
 .rvmrc
+coverage
diff --git a/.vscode/launch.json b/.vscode/launch.json
new file mode 100644
index 000000000..03988ec62
--- /dev/null
+++ b/.vscode/launch.json
@@ -0,0 +1,29 @@
+{
+  // Use IntelliSense to learn about possible attributes.
+  // Hover to view descriptions of existing attributes.
+  // For more information, visit: https://go.microsoft.com/fwlink/?linkid=830387
+  "version": "0.2.0",
+  "configurations": [
+  {
+    "type": "extensionHost",
+    "request": "launch",
+    "name": "Launch Extension",
+    "runtimeExecutable": "${execPath}",
+    "args": [
+      "--extensionDevelopmentPath=${workspaceFolder}"
+    ],
+    "outFiles": [
+      "${workspaceFolder}/out/**/*.js"
+    ],
+    "preLaunchTask": "npm"
+  },
+
+
+    {
+      "name": "Debug Local File",
+      "type": "Ruby",
+      "request": "launch",
+      "program": "${workspaceRoot}"
+    }
+  ]
+}
\ No newline at end of file
diff --git a/lib/date_range.rb b/lib/date_range.rb
new file mode 100644
index 000000000..40572c26f
--- /dev/null
+++ b/lib/date_range.rb
@@ -0,0 +1,28 @@
+require 'date'
+
+module Hotel
+  class DateRange
+    attr_accessor :start_date, :end_date
+
+    def initialize(start_date, end_date)
+      @start_date = start_date
+      @end_date = end_date
+
+      if @start_date >= @end_date || @start_date && end_date == nil
+        raise ArgumentError
+    end
+  end
+
+    def length_of_stay
+      return (@end_date - @start_date) - 1
+    end
+
+    def overlap?(range)
+      if @start_date >= range.end_date || @end_date <= range.start_date
+        return false
+      else
+        return true
+      end
+    end
+  end
+end
\ No newline at end of file
diff --git a/lib/hotel_controller.rb b/lib/hotel_controller.rb
new file mode 100644
index 000000000..0609cc498
--- /dev/null
+++ b/lib/hotel_controller.rb
@@ -0,0 +1,48 @@
+require_relative 'date_range'
+require_relative 'reservation'
+module Hotel
+  class HotelController
+    attr_reader :reservations, :rooms
+    def initialize
+      @reservations = []
+      @rooms = []
+      (1..20).each do |room|
+        @rooms << room
+      end
+    end
+    # Wave 1
+    # def rooms
+    #   return @rooms
+    # end
+
+    def reserve_room(start_date, end_date)
+      if start_date.class != Date || end_date.class != Date
+        raise ArgumentError.new("Please input valid dates")
+      else
+      reservation = Reservation.new(start_date, end_date)
+      @reservations << reservation
+      return reservation
+    end
+  end
+
+    def reservations(date)
+      reservation_list = []
+      @reservations.each do |reservation|
+        if reservation.include?(date)
+        reservation_list << reservation
+          end
+        end
+      return reservation_list
+  end
+
+    # # Wave 2
+    def available_rooms(start_date, end_date)
+      room_list = []
+      range = DateRange.new(start_date, end_date)
+      # start_date and end_date should be instances of class Date
+      taken_rooms = reservations(range)
+      room_list = @rooms - taken_rooms
+     return room_list
+    end
+  end
+end
\ No newline at end of file
diff --git a/lib/reservation.rb b/lib/reservation.rb
new file mode 100644
index 000000000..5195271dc
--- /dev/null
+++ b/lib/reservation.rb
@@ -0,0 +1,17 @@
+require_relative 'date_range'
+module Hotel
+  class Reservation
+    attr_accessor :start_date, :end_date, :room_rate, :room
+    # Feel free to change this method signature as needed. Make sure to update the tests!
+    def initialize(start_date, end_date, room_rate = 200)
+      @start_date = start_date
+      @end_date = end_date
+      @room = room
+      @room_rate = room_rate
+    end
+
+    def cost
+      return DateRange.new(start_date, end_date).length_of_stay * @room_rate
+    end
+  end
+end
\ No newline at end of file
diff --git a/test/date_range_test.rb b/test/date_range_test.rb
new file mode 100644
index 000000000..32b0cb60d
--- /dev/null
+++ b/test/date_range_test.rb
@@ -0,0 +1,53 @@
+require_relative "test_helper"
+
+describe Hotel::DateRange do
+  describe "consructor" do
+    it "Can be initialized with two dates" do
+      start_date = Date.new(2017, 01, 01)
+      end_date = start_date + 3
+
+      range = Hotel::DateRange.new(start_date, end_date)
+
+      expect(range.start_date).must_equal start_date
+      expect(range.end_date).must_equal end_date
+    end
+
+    it "is an an error for negative-length ranges" do
+      start_date = Date.new(2017, 01, 01)
+      end_date = start_date - 3
+
+      expect {Hotel::DateRange.new(start_date, end_date)}.must_raise ArgumentError
+    end
+
+    it "is an error to create a 0-length range" do
+      start_date = 0
+      end_date = 0
+      expect {Hotel::DateRange.new(start_date, end_date)}.must_raise ArgumentError
+    end
+  end
+
+  describe "overlap?" do
+    before do
+      start_date = Date.new(2017, 01, 01)
+      end_date = start_date + 3
+
+      @range = Hotel::DateRange.new(start_date, end_date)
+    end
+
+    it "returns false" do
+      start_date = @range.end_date
+      end_date = @range.end_date
+      test_range = Hotel::DateRange.new(start_date, end_date)
+
+      expect(@range.overlap?(test_range)).must_equal false
+    end
+
+    it "returns true for the same range" do
+      start_date = @range.start_date
+      end_date = @range.end_date
+      test_range = Hotel::DateRange.new(start_date, end_date)
+
+      expect(@range.overlap?(test_range)).must_equal true
+    end
+  end
+end
\ No newline at end of file
diff --git a/test/hotel_controller_test.rb b/test/hotel_controller_test.rb
new file mode 100644
index 000000000..4dacdacdf
--- /dev/null
+++ b/test/hotel_controller_test.rb
@@ -0,0 +1,54 @@
+require_relative "test_helper"
+
+describe Hotel::HotelController do
+  before do
+    @hotel_controller = Hotel::HotelController.new
+    @date = Date.parse("2020-08-04")
+  end
+  describe "wave 1" do
+    describe "rooms" do
+      it "returns a list" do
+        rooms = @hotel_controller.rooms
+        expect(rooms).must_be_kind_of Array
+      end
+    end
+    describe "reserve_room" do
+      it "raises ArgumentError for invalid dates" do
+        start_date = @date
+        end_date = 1
+
+        expect {Hotel::HotelController.new.reserve_room(start_date, end_date)}.must_raise ArgumentError
+      end
+      it "takes two Date objects and returns a Reservation" do
+        start_date = @date
+        end_date = start_date + 3
+        reservation = @hotel_controller.reserve_room(start_date, end_date)
+        expect(reservation).must_be_kind_of Hotel::Reservation
+      end
+    end
+
+    describe "reservations" do
+      it "takes a Date and returns a list of Reservations" do
+        reservation_list = @hotel_controller.reservations(@date)
+
+        expect(reservation_list).must_be_kind_of Array
+        reservation_list.each do |res|
+          res.must_be_kind_of Reservation
+        end
+      end
+    end
+  end
+
+  describe "wave 2" do
+    describe "available_rooms" do
+      it "takes two dates and returns a list" do
+        start_date = @date
+        end_date = start_date + 3
+
+        room_list = @hotel_controller.available_rooms(start_date, end_date)
+
+        expect(room_list).must_be_kind_of Array
+      end
+    end
+  end
+end
\ No newline at end of file
diff --git a/test/reservation_test.rb b/test/reservation_test.rb
new file mode 100644
index 000000000..a8a60ee08
--- /dev/null
+++ b/test/reservation_test.rb
@@ -0,0 +1,20 @@
+require_relative "test_helper"
+
+describe Hotel::Reservation do
+  describe "cost" do
+    it "returns a number" do
+      start_date = Date.new(2017, 01, 01)
+      end_date = start_date + 3
+      room_rate = 200
+      reservation = Hotel::Reservation.new(start_date, end_date, room_rate)
+      expect(reservation.cost).must_be_kind_of Numeric
+    end
+    it "calculates cost accurately" do
+      start_date = Date.new(2017, 01, 01)
+      end_date = start_date + 3
+      room_rate = 200
+      reservation = Hotel::Reservation.new(start_date, end_date, room_rate)
+      expect(reservation.cost).must_equal 400
+    end
+  end
+end
\ No newline at end of file
diff --git a/test/test_helper.rb b/test/test_helper.rb
index c3a7695cf..2d3d808fc 100644
--- a/test/test_helper.rb
+++ b/test/test_helper.rb
@@ -1,8 +1,17 @@
 # Add simplecov
+require 'simplecov'
+SimpleCov.start do
+  add_filter 'test/'
+end
 require "minitest"
 require "minitest/autorun"
 require "minitest/reporters"
 
+require "date"
+
 Minitest::Reporters.use! Minitest::Reporters::SpecReporter.new
 
 # require_relative your lib files here!
+require_relative "../lib/hotel_controller.rb"
+require_relative "../lib/reservation.rb"
+require_relative "../lib/date_range.rb"
\ No newline at end of file