added rspec, and wrote tests for all models

Gemfile

@@ -35,6 +35,11 @@ group :development do
   # Spring speeds up development by keeping your application running in the background. Read more: https://github.com/rails/spring
   gem 'spring'
   gem 'spring-watcher-listen', '~> 2.0.0'
+  gem 'rspec-rails', '>= 3.5.0'
+  gem 'shoulda-matchers', '~> 3.1'
+  gem 'database_cleaner'
+  gem 'factory_girl'
+  gem 'faker'
 end
 
 # Windows does not include zoneinfo files, so bundle the tzinfo-data gem

Gemfile.lock

@@ -43,7 +43,13 @@ GEM
     byebug (10.0.0)
     concurrent-ruby (1.0.5)
     crass (1.0.3)
+    database_cleaner (1.6.2)
+    diff-lcs (1.3)
     erubi (1.7.1)
+    factory_girl (4.9.0)
+      activesupport (>= 3.0.0)
+    faker (1.8.7)
+      i18n (>= 0.7)
     ffi (1.9.23)
     globalid (0.4.1)
       activesupport (>= 4.2.0)
@@ -97,7 +103,26 @@ GEM
     rb-fsevent (0.10.3)
     rb-inotify (0.9.10)
       ffi (>= 0.5.0, < 2)
+    rspec-core (3.7.1)
+      rspec-support (~> 3.7.0)
+    rspec-expectations (3.7.0)
+      diff-lcs (>= 1.2.0, < 2.0)
+      rspec-support (~> 3.7.0)
+    rspec-mocks (3.7.0)
+      diff-lcs (>= 1.2.0, < 2.0)
+      rspec-support (~> 3.7.0)
+    rspec-rails (3.7.2)
+      actionpack (>= 3.0)
+      activesupport (>= 3.0)
+      railties (>= 3.0)
+      rspec-core (~> 3.7.0)
+      rspec-expectations (~> 3.7.0)
+      rspec-mocks (~> 3.7.0)
+      rspec-support (~> 3.7.0)
+    rspec-support (3.7.1)
     ruby_dep (1.5.0)
+    shoulda-matchers (3.1.2)
+      activesupport (>= 4.0.0)
     spring (2.0.2)
       activesupport (>= 4.2)
     spring-watcher-listen (2.0.1)
@@ -123,10 +148,15 @@ PLATFORMS
 
 DEPENDENCIES
   byebug
+  database_cleaner
+  factory_girl
+  faker
   listen (>= 3.0.5, < 3.2)
   pg (~> 0.18)
   puma (~> 3.7)
   rails (~> 5.1.1)
+  rspec-rails (>= 3.5.0)
+  shoulda-matchers (~> 3.1)
   spring
   spring-watcher-listen (~> 2.0.0)
   tzinfo-data

app/models/guest.rb

@@ -1,2 +1,4 @@
 class Guest < ApplicationRecord
+  validates :name, :email, presence: true
+  validates :email, uniqueness: true, format: { with: /\A[-a-z0-9_+\.]+\@([-a-z0-9]+\.)+[a-z0-9]{2,4}\z/i }
 end

app/models/reservation.rb

@@ -3,4 +3,13 @@ class Reservation < ApplicationRecord
   belongs_to :guest
   belongs_to :restaurant_table
   belongs_to :restaurant_shift
+
+  validates_associated :restaurant, :guest, :restaurant_table, :restaurant_shift
+  validates :guest_count, :reservation_time, :restaurant_id, :restaurant_shift_id, :restaurant_table_id, presence: true
+  before_save :valid_guest_count
+
+private
+  def valid_guest_count
+    guest_count > 0
+  end
 end

app/models/restaurant.rb

@@ -1,2 +1,4 @@
 class Restaurant < ApplicationRecord
+  validates :name, :email, :phone_number, presence: true
+  validates :email, uniqueness: true, format: { with: /\A[-a-z0-9_+\.]+\@([-a-z0-9]+\.)+[a-z0-9]{2,4}\z/i }
 end

app/models/restaurant_shift.rb

@@ -1,3 +1,12 @@
 class RestaurantShift < ApplicationRecord
   belongs_to :restaurant
+
+  validates_associated :restaurant
+  validates :start_time, :end_time, :name, :restaurant_id, presence: true
+  before_save :has_no_conflicts
+
+private
+  def has_no_conflicts
+    return true
+  end
 end

app/models/restaurant_table.rb

@@ -1,3 +1,13 @@
 class RestaurantTable < ApplicationRecord
   belongs_to :restaurant
+
+  validates_associated :restaurant
+  validates :minimum_count, :maximum_count, :restaurant_id, presence: true
+  before_save :valid_table_count
+
+  private
+    def valid_table_count
+      maximum_count > minimum_count && minimum_count > 0
+    end
+
 end

db/migrate/20180321014957_create_restaurant_shifts.rb

@@ -2,8 +2,8 @@ class CreateRestaurantShifts < ActiveRecord::Migration[5.1]
   def change
     create_table :restaurant_shifts do |t|
       t.references :restaurant, foreign_key: true
-      t.date :start_time
-      t.date :end_time
+      t.time :start_time
+      t.time :end_time
       t.string :name
 
       t.timestamps

spec/factories/factories.rb

@@ -0,0 +1,36 @@
+require "faker"
+FactoryGirl.define do
+
+  factory :guest do
+    name Faker::Name.name
+    email Faker::Internet.email
+  end
+
+  factory :restaurant do
+    name Faker::Name.name
+    email Faker::Internet.email
+    phone_number Faker::PhoneNumber.phone_number
+  end
+
+  factory :restaurant_table do
+    maximum_count Faker::Number.between(3, 10)
+    minimum_count Faker::Number.between(1,2)
+    restaurant { Restaurant.first || association(:restaurant) }
+  end
+
+  factory :restaurant_shift do
+    name Faker::Name.name
+    start_time Faker::Time.between(2.days.ago, Date.today, :morning)
+    end_time Faker::Time.between(2.days.ago, Date.today, :night)
+    restaurant { Restaurant.first || association(:restaurant) }
+  end
+
+  factory :reservation do
+    guest_count Faker::Number.between(1, 100)
+    reservation_time Faker::Time.forward(2, :morning)
+    restaurant { Restaurant.first || association(:restaurant) }
+    guest { Guest.first || association(:guest) }
+    restaurant_table { RestaurantTable.first || association(:restaurant_table) }
+    restaurant_shift { RestaurantShift.first || association(:restaurant_shift) }
+  end
+end

spec/models/guest_spec.rb

@@ -0,0 +1,14 @@
+require 'rails_helper'
+
+RSpec.describe Guest, type: :model do
+
+  it 'has a valid factory' do
+    expect(FactoryGirl.create(:guest)).to be_valid
+  end
+
+  context 'validations' do
+    it { is_expected.to validate_presence_of :email }
+    it { is_expected.to validate_uniqueness_of :email }
+    it { is_expected.to validate_presence_of :name }
+  end
+end

spec/models/reservations_spec.rb

@@ -0,0 +1,16 @@
+require 'rails_helper'
+
+RSpec.describe Reservation, type: :model do
+
+  it 'has a valid factory' do
+    expect(FactoryGirl.create(:reservation)).to be_valid
+  end
+
+  context 'validations' do
+    it { is_expected.to validate_presence_of :guest_count }
+    it { is_expected.to validate_presence_of :reservation_time }
+    it { is_expected.to validate_presence_of :restaurant_id }
+    it { is_expected.to validate_presence_of :restaurant_table_id }
+    it { is_expected.to validate_presence_of :restaurant_shift_id }
+  end
+end

spec/models/restaurant_shift_spec.rb

@@ -0,0 +1,15 @@
+require 'rails_helper'
+
+RSpec.describe RestaurantShift, type: :model do
+
+  it 'has a valid factory' do
+    expect(FactoryGirl.create(:restaurant_shift)).to be_valid
+  end
+
+  context 'validations' do
+    it { is_expected.to validate_presence_of :start_time }
+    it { is_expected.to validate_presence_of :end_time }
+    it { is_expected.to validate_presence_of :name }
+    it { is_expected.to validate_presence_of :restaurant_id }
+  end
+end

spec/models/restaurant_spec.rb

@@ -0,0 +1,15 @@
+require 'rails_helper'
+
+RSpec.describe Restaurant, type: :model do
+
+  it 'has a valid factory' do
+    expect(FactoryGirl.create(:restaurant)).to be_valid
+  end
+
+  context 'validations' do
+    it { is_expected.to validate_presence_of :email }
+    it { is_expected.to validate_uniqueness_of :email }
+    it { is_expected.to validate_presence_of :name }
+    it { is_expected.to validate_presence_of :phone_number }
+  end
+end

spec/models/restaurant_table_spec.rb

@@ -0,0 +1,14 @@
+require 'rails_helper'
+
+RSpec.describe RestaurantTable, type: :model do
+
+  it 'has a valid factory' do
+    expect(FactoryGirl.create(:restaurant_table)).to be_valid
+  end
+
+  context 'validations' do
+    it { is_expected.to validate_presence_of :maximum_count }
+    it { is_expected.to validate_presence_of :minimum_count }
+    it { is_expected.to validate_presence_of :restaurant_id }
+  end
+end

spec/rails_helper.rb

@@ -0,0 +1,64 @@
+# This file is copied to spec/ when you run 'rails generate rspec:install'
+require 'spec_helper'
+ENV['RAILS_ENV'] ||= 'test'
+require File.expand_path('../../config/environment', __FILE__)
+# Prevent database truncation if the environment is production
+abort("The Rails environment is running in production mode!") if Rails.env.production?
+require 'rspec/rails'
+require 'shoulda/matchers'
+require 'faker'
+require 'database_cleaner'
+require 'factory_girl'
+require 'support/shoulda'
+require 'support/database_cleaner'
+require 'factories/factories.rb'
+# Add additional requires below this line. Rails is not loaded until this point!
+
+# Requires supporting ruby files with custom matchers and macros, etc, in
+# spec/support/ and its subdirectories. Files matching `spec/**/*_spec.rb` are
+# run as spec files by default. This means that files in spec/support that end
+# in _spec.rb will both be required and run as specs, causing the specs to be
+# run twice. It is recommended that you do not name files matching this glob to
+# end with _spec.rb. You can configure this pattern with the --pattern
+# option on the command line or in ~/.rspec, .rspec or `.rspec-local`.
+#
+# The following line is provided for convenience purposes. It has the downside
+# of increasing the boot-up time by auto-requiring all files in the support
+# directory. Alternatively, in the individual `*_spec.rb` files, manually
+# require only the support files necessary.
+#
+# Dir[Rails.root.join('spec/support/**/*.rb')].each { |f| require f }
+
+# Checks for pending migrations and applies them before tests are run.
+# If you are not using ActiveRecord, you can remove this line.
+ActiveRecord::Migration.maintain_test_schema!
+
+RSpec.configure do |config|
+  # Remove this line if you're not using ActiveRecord or ActiveRecord fixtures
+  config.fixture_path = "#{::Rails.root}/spec/fixtures"
+
+  # If you're not using ActiveRecord, or you'd prefer not to run each of your
+  # examples within a transaction, remove the following line or assign false
+  # instead of true.
+  config.use_transactional_fixtures = true
+
+  # RSpec Rails can automatically mix in different behaviours to your tests
+  # based on their file location, for example enabling you to call `get` and
+  # `post` in specs under `spec/controllers`.
+  #
+  # You can disable this behaviour by removing the line below, and instead
+  # explicitly tag your specs with their type, e.g.:
+  #
+  #     RSpec.describe UsersController, :type => :controller do
+  #       # ...
+  #     end
+  #
+  # The different available types are documented in the features, such as in
+  # https://relishapp.com/rspec/rspec-rails/docs
+  config.infer_spec_type_from_file_location!
+
+  # Filter lines from Rails gems in backtraces.
+  config.filter_rails_from_backtrace!
+  # arbitrary gems may also be filtered via:
+  # config.filter_gems_from_backtrace("gem name")
+end