diff --git a/.ruby-version b/.ruby-version
index 2078687..c1026d2 100644
--- a/.ruby-version
+++ b/.ruby-version
@@ -1 +1 @@
-ruby-2.3-head
+ruby-2.3.1
diff --git a/Gemfile b/Gemfile
index d96735c..82d12eb 100644
--- a/Gemfile
+++ b/Gemfile
@@ -2,6 +2,7 @@ source 'https://rubygems.org'
 
 gem 'rails', '4.2.6'
 gem 'pg', '~> 0.15'
+gem 'sprockets', '3.6.3'
 gem 'sass-rails', '~> 5.0'
 gem 'uglifier', '>= 1.3.0'
 gem 'coffee-rails', '~> 4.1.0'
@@ -22,6 +23,9 @@ gem 'private_pub'
 gem 'skim'
 gem 'gon'
 gem 'responders'
+gem 'omniauth'
+gem 'omniauth-facebook'
+gem 'omniauth-twitter'
 
 # gem 'unicorn'
 gem 'thin'
@@ -43,6 +47,8 @@ group :test do
   gem 'capybara-webkit'
 end
 
+gem 'capybara-email'
+
 group :development do
   gem 'web-console', '~> 2.0'
   gem 'pry'
@@ -57,4 +63,6 @@ group :development do
   gem 'rails_best_practices'
 
   gem 'spring'
+
+  gem 'letter_opener'
 end
diff --git a/Gemfile.lock b/Gemfile.lock
index 5730254..81b80b3 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -39,7 +39,7 @@ GEM
     addressable (2.4.0)
     arel (6.0.3)
     ast (2.3.0)
-    autoprefixer-rails (6.3.7)
+    autoprefixer-rails (6.4.0.3)
       execjs
     bcrypt (3.1.11)
     better_errors (2.1.1)
@@ -61,6 +61,9 @@ GEM
       rack (>= 1.0.0)
       rack-test (>= 0.5.4)
       xpath (~> 2.0)
+    capybara-email (2.5.0)
+      capybara (~> 2.4)
+      mail
     capybara-webkit (1.11.1)
       capybara (>= 2.3.0, < 2.8.0)
       json
@@ -71,7 +74,7 @@ GEM
       mime-types (>= 1.16)
       mimemagic (>= 0.3.0)
     cocoon (1.2.9)
-    code_analyzer (0.4.5)
+    code_analyzer (0.4.7)
       sexp_processor
     coderay (1.1.1)
     coffee-rails (4.1.1)
@@ -83,7 +86,7 @@ GEM
     coffee-script-source (1.10.0)
     concurrent-ruby (1.0.2)
     cookiejar (0.3.3)
-    daemons (1.2.3)
+    daemons (1.2.4)
     database_cleaner (1.5.3)
     debug_inspector (0.0.2)
     devise (4.2.0)
@@ -111,6 +114,8 @@ GEM
       railties (>= 3.0.0)
     faker (1.6.6)
       i18n (~> 0.5)
+    faraday (0.9.2)
+      multipart-post (>= 1.2, < 3)
     faye (1.2.2)
       cookiejar (>= 0.3.0)
       em-http-request (>= 0.3.0)
@@ -142,22 +147,26 @@ GEM
       shellany (~> 0.0)
       thor (>= 0.18.1)
     guard-compat (1.2.1)
-    guard-rspec (4.7.2)
+    guard-rspec (4.7.3)
       guard (~> 2.1)
       guard-compat (~> 1.1)
       rspec (>= 2.99.0, < 4.0)
+    hashie (3.4.4)
     http_parser.rb (0.6.0)
     i18n (0.7.0)
     jbuilder (2.6.0)
       activesupport (>= 3.0.0, < 5.1)
       multi_json (~> 1.2)
-    jquery-rails (4.1.1)
+    jquery-rails (4.2.1)
       rails-dom-testing (>= 1, < 3)
       railties (>= 4.2.0)
       thor (>= 0.14, < 2.0)
     json (1.8.3)
+    jwt (1.5.4)
     launchy (2.4.3)
       addressable (~> 2.3)
+    letter_opener (1.4.1)
+      launchy (~> 2.2)
     listen (3.1.5)
       rb-fsevent (~> 0.9, >= 0.9.4)
       rb-inotify (~> 0.9, >= 0.9.7)
@@ -175,17 +184,40 @@ GEM
     mime-types (3.1)
       mime-types-data (~> 3.2015)
     mime-types-data (3.2016.0521)
-    mimemagic (0.3.1)
+    mimemagic (0.3.2)
     mini_portile2 (2.1.0)
     minitest (5.9.0)
     multi_json (1.12.1)
+    multi_xml (0.5.5)
+    multipart-post (2.0.0)
     nenv (0.3.0)
     nokogiri (1.6.8)
       mini_portile2 (~> 2.1.0)
       pkg-config (~> 1.1.7)
-    notiffany (0.1.0)
+    notiffany (0.1.1)
       nenv (~> 0.1)
       shellany (~> 0.0)
+    oauth (0.5.1)
+    oauth2 (1.2.0)
+      faraday (>= 0.8, < 0.10)
+      jwt (~> 1.0)
+      multi_json (~> 1.3)
+      multi_xml (~> 0.5)
+      rack (>= 1.2, < 3)
+    omniauth (1.3.1)
+      hashie (>= 1.2, < 4)
+      rack (>= 1.0, < 3)
+    omniauth-facebook (4.0.0)
+      omniauth-oauth2 (~> 1.2)
+    omniauth-oauth (1.1.0)
+      oauth
+      omniauth (~> 1.0)
+    omniauth-oauth2 (1.4.0)
+      oauth2 (~> 1.0)
+      omniauth (~> 1.2)
+    omniauth-twitter (1.2.1)
+      json (~> 1.3)
+      omniauth-oauth (~> 1.1)
     orm_adapter (0.5.0)
     parser (2.3.1.2)
       ast (~> 2.2)
@@ -253,13 +285,13 @@ GEM
     remotipart (1.2.1)
     request_store (1.3.1)
     require_all (1.3.3)
-    responders (2.2.0)
+    responders (2.3.0)
       railties (>= 4.2.0, < 5.1)
     rspec (3.5.0)
       rspec-core (~> 3.5.0)
       rspec-expectations (~> 3.5.0)
       rspec-mocks (~> 3.5.0)
-    rspec-core (3.5.1)
+    rspec-core (3.5.2)
       rspec-support (~> 3.5.0)
     rspec-expectations (3.5.0)
       diff-lcs (>= 1.2.0, < 2.0)
@@ -267,7 +299,7 @@ GEM
     rspec-mocks (3.5.0)
       diff-lcs (>= 1.2.0, < 2.0)
       rspec-support (~> 3.5.0)
-    rspec-rails (3.5.1)
+    rspec-rails (3.5.2)
       actionpack (>= 3.0)
       activesupport (>= 3.0)
       railties (>= 3.0)
@@ -283,7 +315,7 @@ GEM
       ruby-progressbar (~> 1.7)
       unicode-display_width (~> 1.0, >= 1.0.1)
     ruby-progressbar (1.8.1)
-    ruby_dep (1.3.1)
+    ruby_dep (1.4.0)
     sass (3.4.22)
     sass-rails (5.0.6)
       railties (>= 4.0.0, < 6)
@@ -314,7 +346,7 @@ GEM
     spring (1.7.2)
     spring-commands-rspec (1.0.4)
       spring (>= 0.9.1)
-    sprockets (3.7.0)
+    sprockets (3.6.3)
       concurrent-ruby (~> 1.0)
       rack (> 1, < 3)
     sprockets-rails (3.1.1)
@@ -329,12 +361,12 @@ GEM
     thor (0.19.1)
     thread_safe (0.3.5)
     tilt (2.0.5)
-    turbolinks (5.0.0)
+    turbolinks (5.0.1)
       turbolinks-source (~> 5)
     turbolinks-source (5.0.0)
     tzinfo (1.2.2)
       thread_safe (~> 0.1)
-    uglifier (3.0.0)
+    uglifier (3.0.2)
       execjs (>= 0.3.0, < 3)
     unicode-display_width (1.1.0)
     warden (1.2.6)
@@ -359,6 +391,7 @@ DEPENDENCIES
   bootstrap-sass (~> 3.3.6)
   byebug (~> 8.0)
   capybara
+  capybara-email
   capybara-webkit
   carrierwave
   cocoon
@@ -372,7 +405,11 @@ DEPENDENCIES
   jbuilder (~> 2.0)
   jquery-rails
   launchy
+  letter_opener
   meta_request
+  omniauth
+  omniauth-facebook
+  omniauth-twitter
   pg (~> 0.15)
   private_pub
   pry
@@ -393,6 +430,7 @@ DEPENDENCIES
   slim-rails
   spring
   spring-commands-rspec
+  sprockets (= 3.6.3)
   thin
   turbolinks
   uglifier (>= 1.3.0)
diff --git a/app/controllers/account_controller.rb b/app/controllers/account_controller.rb
new file mode 100644
index 0000000..6d8c034
--- /dev/null
+++ b/app/controllers/account_controller.rb
@@ -0,0 +1,47 @@
+class AccountController < ApplicationController
+  before_action :check_already_signed_in, only: [:confirm_email]
+  before_action :check_oauth_in_session, only: [:confirm_email]
+
+  def confirm_email
+    if request.patch?
+      email = nil
+      email = params[:user][:email] if params[:user] && params[:user][:email]
+      user = User.where(email: email).first
+      provider = session['devise.oauth_provider']
+      if user.present?
+        set_flash :alert, 'Email already taken.'
+      else
+        User.transaction do
+          @user = User.create(email: email, password: Devise.friendly_token[0, 20])
+          if @user.persisted?
+            @user.identities.create!({
+                provider: provider,
+                uid: session['devise.oauth_uid'].to_s})
+          end
+        end
+        if @user.persisted?
+          set_flash :notice, t('devise.omniauth_callbacks.success', kind: provider.to_s.capitalize)
+          sign_in_and_redirect @user, event: :authentication
+        end
+      end
+    end
+  end
+
+  private
+
+  def check_already_signed_in
+    redirect_to questions_path if signed_in?
+  end
+
+  def check_oauth_in_session
+    if !session['devise.oauth_provider'] && !session['devise.oauth_uid']
+      set_flash :notice, 'Registration done'
+      redirect_to questions_path
+    elsif !session['devise.oauth_provider'] || !session['devise.oauth_uid']
+      session['devise.oauth_provider'] = nil
+      session['devise.oauth_uid'] = nil
+      set_flash :alert, 'Authentication error, try again'
+      redirect_to new_user_session_path
+    end
+  end
+end
diff --git a/app/controllers/application_controller.rb b/app/controllers/application_controller.rb
index 1b8dc55..9056e36 100644
--- a/app/controllers/application_controller.rb
+++ b/app/controllers/application_controller.rb
@@ -10,6 +10,12 @@ class ApplicationController < ActionController::Base
 
   before_action :set_js_current_user
 
+  protected
+
+  def set_flash(scope, message)
+    flash[scope] = message if is_navigational_format?
+  end
+
   private
 
   def set_js_current_user
diff --git a/app/controllers/omniauth_callbacks_controller.rb b/app/controllers/omniauth_callbacks_controller.rb
new file mode 100644
index 0000000..5fc32bf
--- /dev/null
+++ b/app/controllers/omniauth_callbacks_controller.rb
@@ -0,0 +1,43 @@
+class OmniauthCallbacksController < Devise::OmniauthCallbacksController
+  before_action :oauth
+
+  def facebook
+  end
+
+  def twitter
+  end
+
+  private
+
+  def oauth
+    email = nil
+    email = params[:user][:email] if params[:user] && params[:user][:email]
+    auth = request.env['omniauth.auth'] || OmniAuth::AuthHash.new(
+        provider: session['oauth_provider'],
+        uid: session['oauth_uid'],
+        info: {email: email})
+    if auth
+      @user = User.find_for_oauth(auth)
+      if @user.nil? && auth && auth.provider && auth.uid
+        store_auth auth
+        redirect_to account_confirm_email_path
+      elsif @user&.persisted?
+        set_flash_message :notice, :success, kind: auth.provider.to_s.capitalize if is_navigational_format?
+        sign_in_and_redirect @user, event: :authentication
+      else
+        failure_redirect
+      end
+    else
+      failure_redirect
+    end
+  end
+
+  def store_auth(auth)
+    session['devise.oauth_provider'] = auth.provider
+    session['devise.oauth_uid'] = auth.uid
+  end
+
+  def failure_redirect
+    redirect_to new_user_registration_path, alert: 'Authentication failure'
+  end
+end
diff --git a/app/models/identity.rb b/app/models/identity.rb
new file mode 100644
index 0000000..0937cd3
--- /dev/null
+++ b/app/models/identity.rb
@@ -0,0 +1,6 @@
+class Identity < ActiveRecord::Base
+  belongs_to :user
+
+  validates :user_id, :provider, presence: true
+  validates :uid, presence: true, uniqueness: {scope: :provider}
+end
diff --git a/app/models/user.rb b/app/models/user.rb
index 3aab7c2..545e96a 100644
--- a/app/models/user.rb
+++ b/app/models/user.rb
@@ -2,9 +2,34 @@ class User < ActiveRecord::Base
   # Include default devise modules. Others available are:
   # :confirmable, :lockable, :timeoutable and :omniauthable
   devise :database_authenticatable, :registerable,
-         :recoverable, :rememberable, :trackable, :validatable
+      :recoverable, :rememberable, :trackable, :validatable,
+      :confirmable,
+      :omniauthable, omniauth_providers: [:facebook, :twitter]
 
+  has_many :identities, dependent: :destroy
   has_many :questions, dependent: :destroy
   has_many :answers, dependent: :destroy
   has_many :comments, dependent: :destroy
+
+  class << self
+    def find_for_oauth(auth)
+      return nil unless auth
+
+      identity = Identity.where(provider: auth.provider, uid: auth.uid.to_s).first
+      return identity.user if identity
+
+      email = auth.info[:email] if auth.info
+      return nil unless email
+
+      user = User.where(email: email).first
+      unless user
+        password = Devise.friendly_token(20)
+        user = User.new(email: email, password: password, password_confirmation: password)
+        user.save
+      end
+
+      user.identities.create(provider: auth.provider, uid: auth.uid) if user
+      user
+    end
+  end
 end
diff --git a/app/views/account/confirm_email.slim b/app/views/account/confirm_email.slim
new file mode 100644
index 0000000..f5bb479
--- /dev/null
+++ b/app/views/account/confirm_email.slim
@@ -0,0 +1,15 @@
+h2 Enter your email to proceed
+
+.row
+  .col-sm-12
+    = render 'shared/form_errors', object: @user
+
+.row
+  .col-sm-12
+    = form_for :user, url: account_confirm_email_path, method: :patch do |f|
+      .form-group
+        = f.label :email
+        = f.email_field :email, class: 'form-control', placeholder: 'enter@email.here'
+        /= email_field_tag :email, params[:email], class: 'form-control', placeholder: 'enter@email.here'
+      .form-group
+        = f.submit 'Validate Email', class: 'btn btn-primary pull-right'
diff --git a/app/views/shared/_form_errors.slim b/app/views/shared/_form_errors.slim
index 4df8c99..dc05cf1 100644
--- a/app/views/shared/_form_errors.slim
+++ b/app/views/shared/_form_errors.slim
@@ -1,4 +1,4 @@
-- if object.errors.any?
+- if object&.errors&.any?
   #error_explanation
     .alert.alert-danger
       p.lead Form has an error(s):
diff --git a/bin/comet b/bin/comet
index e600183..4053693 100755
--- a/bin/comet
+++ b/bin/comet
@@ -1,5 +1,5 @@
 #!/bin/sh
 
 #rackup private_pub.ru -s thin -E development
-rackup private_pub.ru -s thin -E production
+rackup -D private_pub.ru -s thin -E production
 
diff --git a/circle.yml b/circle.yml
new file mode 100644
index 0000000..46f7575
--- /dev/null
+++ b/circle.yml
@@ -0,0 +1,11 @@
+machine:
+  timezone:
+    Europe/Moscow
+  ruby:
+    version: 2.3.0
+
+dependencies:
+  pre:
+    - gem install bundler --pre
+  post:
+    - bundle exec ./bin/comet
diff --git a/config/environments/development.rb b/config/environments/development.rb
index b2a1347..c469ec5 100644
--- a/config/environments/development.rb
+++ b/config/environments/development.rb
@@ -15,7 +15,8 @@
 
   config.action_mailer.perform_deliveries = true
   config.action_mailer.raise_delivery_errors = true
-  config.action_mailer.delivery_method = :sendmail
+  # config.action_mailer.delivery_method = :sendmail
+  config.action_mailer.delivery_method = :letter_opener
   config.action_mailer.default_options = { from: 'e@varnakov.ru' }
 
   # Print deprecation notices to the Rails logger.
diff --git a/config/environments/test.rb b/config/environments/test.rb
index 1c19f08..aecc6eb 100644
--- a/config/environments/test.rb
+++ b/config/environments/test.rb
@@ -30,6 +30,8 @@
   # The :test delivery method accumulates sent emails in the
   # ActionMailer::Base.deliveries array.
   config.action_mailer.delivery_method = :test
+  config.action_mailer.perform_deliveries = true
+  config.action_mailer.default_url_options = { host: 'localhost', port: 3001 }
 
   # Randomize the order test cases are executed.
   config.active_support.test_order = :random
@@ -39,4 +41,10 @@
 
   # Raises error for missing translations
   # config.action_view.raise_on_missing_translations = true
+
+  # Enable stdout logger
+  config.logger = Logger.new(STDOUT)
+
+  # Set log level
+  config.log_level = :DEBUG
 end
diff --git a/config/initializers/devise.rb b/config/initializers/devise.rb
index 09f665c..bc19a1e 100644
--- a/config/initializers/devise.rb
+++ b/config/initializers/devise.rb
@@ -12,13 +12,13 @@
   # Configure the e-mail address which will be shown in Devise::Mailer,
   # note that it will be overwritten if you use your own mailer class
   # with default "from" parameter.
-  config.mailer_sender = 'please-change-me-at-config-initializers-devise@example.com'
+  config.mailer_sender = 'e@varnakov.ru'
 
   # Configure the class responsible to send e-mails.
-  # config.mailer = 'Devise::Mailer'
+  config.mailer = 'Devise::Mailer'
 
   # Configure the parent class responsible to send e-mails.
-  # config.parent_mailer = 'ActionMailer::Base'
+  config.parent_mailer = 'ActionMailer::Base'
 
   # ==> ORM configuration
   # Load and configure the ORM. Supports :active_record (default) and
@@ -114,6 +114,7 @@
   # access will be blocked just in the third day. Default is 0.days, meaning
   # the user cannot access the website without confirming their account.
   # config.allow_unconfirmed_access_for = 2.days
+  config.allow_unconfirmed_access_for = 2.days if Rails.env.test?
 
   # A period that the user is allowed to confirm their account before their
   # token becomes invalid. For example, if set to 3.days, the user can confirm
@@ -242,6 +243,10 @@
   # Add a new OmniAuth provider. Check the wiki for more information on setting
   # up on your models and hooks.
   # config.omniauth :github, 'APP_ID', 'APP_SECRET', scope: 'user,public_repo'
+  config.omniauth :facebook, Rails.application.secrets.facebook_app_id,
+                  Rails.application.secrets.facebook_app_secret, scope: [:email]
+  config.omniauth :twitter, Rails.application.secrets.twitter_app_id,
+                  Rails.application.secrets.twitter_app_secret
 
   # ==> Warden configuration
   # If you want to use other strategies, that are not supported by Devise, or
diff --git a/config/routes.rb b/config/routes.rb
index ba20d7a..0b311d3 100644
--- a/config/routes.rb
+++ b/config/routes.rb
@@ -1,7 +1,8 @@
 Rails.application.routes.draw do
   root 'questions#index'
 
-  devise_for :users
+  devise_for :users, controllers: { omniauth_callbacks: :omniauth_callbacks}
+  match 'account/confirm_email', via: [:get, :patch]
 
   concern :rateable do
     member do
diff --git a/config/secrets.yml b/config/secrets.yml
index ff4b40e..bae4c49 100644
--- a/config/secrets.yml
+++ b/config/secrets.yml
@@ -12,6 +12,10 @@
 
 development:
   secret_key_base: b95a307aeef7b76a6805c4f196f9f228bd8b7e40d78dcae5b003e55b851b299189b273e11148c542a8a5e06b44c1b97fcabb2922a1a02e515e498998a228766f
+  facebook_app_id: 1111783555576872
+  facebook_app_secret: cc941c1c69c4df0cd160e2bca79fce00
+  twitter_app_id: 1BeipKxAypv1y4DDbzLN30kja
+  twitter_app_secret: tAJ0d57JXZpyITrYy8f7kUvlFpcghzav4KwZBthTv2WfKX7IUH
 
 test:
   secret_key_base: 409050a6e334ef505b4403e78afbe40e18007505904d27227ce6302b311a1b2084c3f0028f4a06fa86a718e7e4846e492a20d26f768c7c9672828e9c5fef391b
diff --git a/db/migrate/20160822233027_create_identities.rb b/db/migrate/20160822233027_create_identities.rb
new file mode 100644
index 0000000..2634a1a
--- /dev/null
+++ b/db/migrate/20160822233027_create_identities.rb
@@ -0,0 +1,13 @@
+class CreateIdentities < ActiveRecord::Migration
+  def change
+    create_table :identities do |t|
+      t.references :user, index: true, foreign_key: true
+      t.string :provider, null: false
+      t.string :uid, null: false
+
+      t.timestamps null: false
+    end
+
+    add_index :identities, [:provider, :uid]
+  end
+end
diff --git a/db/migrate/20160829190531_add_confirmable_to_devise.rb b/db/migrate/20160829190531_add_confirmable_to_devise.rb
new file mode 100644
index 0000000..f94d2a6
--- /dev/null
+++ b/db/migrate/20160829190531_add_confirmable_to_devise.rb
@@ -0,0 +1,18 @@
+class AddConfirmableToDevise < ActiveRecord::Migration
+  def up
+    add_column :users, :confirmation_token, :string
+    add_column :users, :confirmed_at, :datetime
+    add_column :users, :confirmation_sent_at, :datetime
+    add_column :users, :unconfirmed_email, :string
+
+    add_index :users, :confirmation_token, unique: true
+
+    User.all.update_all confirmed_at: Time.now
+  end
+
+  def down
+    remove_index :users, :confirmation_token
+
+    remove_columns :users, :confirmation_token, :confirmed_at, :confirmation_sent_at, :unconfirmed_email
+  end
+end
diff --git a/db/schema.rb b/db/schema.rb
index 42a97fd..de4641d 100644
--- a/db/schema.rb
+++ b/db/schema.rb
@@ -11,7 +11,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 20160806125740) do
+ActiveRecord::Schema.define(version: 20160829190531) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
@@ -48,6 +48,17 @@
     t.datetime "updated_at",       null: false
   end
 
+  create_table "identities", force: :cascade do |t|
+    t.integer  "user_id"
+    t.string   "provider",   null: false
+    t.string   "uid",        null: false
+    t.datetime "created_at", null: false
+    t.datetime "updated_at", null: false
+  end
+
+  add_index "identities", ["provider", "uid"], name: "index_identities_on_provider_and_uid", using: :btree
+  add_index "identities", ["user_id"], name: "index_identities_on_user_id", using: :btree
+
   create_table "questions", force: :cascade do |t|
     t.string   "topic",      limit: 200,             null: false
     t.text     "body",                               null: false
@@ -84,14 +95,20 @@
     t.datetime "last_sign_in_at"
     t.inet     "current_sign_in_ip"
     t.inet     "last_sign_in_ip"
+    t.string   "confirmation_token"
+    t.datetime "confirmed_at"
+    t.datetime "confirmation_sent_at"
+    t.string   "unconfirmed_email"
   end
 
+  add_index "users", ["confirmation_token"], name: "index_users_on_confirmation_token", unique: true, using: :btree
   add_index "users", ["email"], name: "index_users_on_email", unique: true, using: :btree
   add_index "users", ["reset_password_token"], name: "index_users_on_reset_password_token", unique: true, using: :btree
 
   add_foreign_key "answers", "questions"
   add_foreign_key "answers", "users"
   add_foreign_key "comments", "users"
+  add_foreign_key "identities", "users"
   add_foreign_key "questions", "users"
   add_foreign_key "ratings", "users"
 end
diff --git a/spec/controllers/account_controller_spec.rb b/spec/controllers/account_controller_spec.rb
new file mode 100644
index 0000000..40ede5c
--- /dev/null
+++ b/spec/controllers/account_controller_spec.rb
@@ -0,0 +1,130 @@
+require 'rails_helper'
+
+describe AccountController do
+  let!(:user) { create(:user) }
+
+  describe 'GET #confirm_email' do
+    subject { get :confirm_email }
+
+    context 'as unauthenticated user' do
+      context 'with valid OAuth data in session' do
+        before do
+          session['devise.oauth_provider'] = generate(:provider)
+          session['devise.oauth_uid'] = generate(:uid)
+        end
+
+        it { is_expected.to have_http_status :success }
+        it { is_expected.to render_template :confirm_email }
+      end
+
+      context 'with invalid OAuth data in session' do
+        before do
+          session['devise.oauth_provider'] = generate(:provider)
+          session['devise.uid'] = nil
+        end
+
+        it { is_expected.to have_http_status :redirect }
+        it { is_expected.to redirect_to new_user_session_path }
+      end
+
+      context 'with no OAuth data in session' do
+        it { is_expected.to have_http_status :redirect }
+        it { is_expected.to redirect_to questions_path }
+      end
+    end
+
+    context 'as authenticated user' do
+      sign_in_user
+
+      before { get :confirm_email }
+
+      it { is_expected.to have_http_status :redirect }
+      it { is_expected.to redirect_to questions_path }
+    end
+  end
+
+  describe 'PATCH #confirm_email' do
+    let(:email) { generate(:email) }
+    subject (:confirm_email) { patch :confirm_email, user: {email: email} }
+
+    context 'as unauthenticated user' do
+      context 'with valid OAuth data in session' do
+        before do
+          session['devise.oauth_provider'] = generate(:provider)
+          session['devise.oauth_uid'] = generate(:uid)
+        end
+
+        context 'with correct email' do
+          it { is_expected.to have_http_status :redirect }
+
+          it 'should assign User object to @user' do
+            confirm_email
+            expect(assigns(:user)).to be_a User
+          end
+
+          context 'for new user' do
+            it 'should create new User instance' do
+              expect { confirm_email }.to change(User, :count).by(1)
+            end
+
+            it 'should create new Identity for the User' do
+              expect { confirm_email }.to change(Identity, :count).by(1)
+            end
+
+            it 'should set given email for new User' do
+              confirm_email
+              expect(assigns(:user).email).to eq email
+            end
+          end
+
+          context 'for existing user' do
+            subject(:confirm_email) { patch :confirm_email, email: user.email }
+
+            it 'shouldn\'t create new User instance' do
+              expect { confirm_email }.not_to change(User, :count)
+            end
+
+            it 'shouldn\'t create new Identitities' do
+              expect { confirm_email }.not_to change(Identity, :count)
+            end
+          end
+        end
+
+        context 'with invalid (empty) email' do
+          subject(:confirm_email) { patch :confirm_email }
+
+          it { is_expected.to have_http_status :success }
+          it { is_expected.to render_template :confirm_email }
+
+          it 'shouldn\'t create new Identitities' do
+            expect { confirm_email }.not_to change(Identity, :count)
+          end
+        end
+      end
+
+      context 'with invalid OAuth data in session' do
+        before do
+          session['devise.oauth_provider'] = generate(:provider)
+          session['devise.uid'] = nil
+        end
+
+        it { is_expected.to have_http_status :redirect }
+        it { is_expected.to redirect_to new_user_session_path }
+      end
+
+      context 'with no OAuth data in session' do
+        it { is_expected.to have_http_status :redirect }
+        it { is_expected.to redirect_to questions_path }
+      end
+    end
+
+    context 'as authenticated user' do
+      sign_in_user
+
+      before { get :confirm_email }
+
+      it { is_expected.to have_http_status :redirect }
+      it { is_expected.to redirect_to questions_path }
+    end
+  end
+end
diff --git a/spec/controllers/omniauth_callbacks_controller_spec.rb b/spec/controllers/omniauth_callbacks_controller_spec.rb
new file mode 100644
index 0000000..9f4e5ff
--- /dev/null
+++ b/spec/controllers/omniauth_callbacks_controller_spec.rb
@@ -0,0 +1,59 @@
+require 'rails_helper'
+
+shared_examples :oauth_callback do
+  let(:user) { create(:user) }
+  before { request.env['devise.mapping'] = Devise.mappings[:user] }
+
+
+  context 'empty request' do
+    subject { get provider }
+    it { is_expected.to redirect_to new_user_registration_path }
+  end
+
+  context 'email not given' do
+    before do
+      request.env['omniauth.auth'] = OmniAuth::AuthHash.new(provider: provider.to_s, uid: '123456', info: {email: nil})
+      get provider
+    end
+
+    it 'stores data in session' do
+      expect(session['devise.oauth_provider']).to eq provider.to_s
+      expect(session['devise.oauth_uid']).to eq '123456'
+    end
+
+    it { should_not be_user_signed_in }
+    it { expect(response).to redirect_to account_confirm_email_path }
+  end
+
+  context 'user does not exist' do
+    before do
+      request.env['omniauth.auth'] = OmniAuth::AuthHash.new(provider: provider.to_s, uid: '123456', info: {email: 'new-user@email.com'})
+      get provider
+    end
+
+    it 'assigns user to @user' do
+      expect(assigns(:user)).to be_a(User)
+    end
+  end
+
+  context 'nulled credentials' do
+    before do
+      request.env['omniauth.auth'] = OmniAuth::AuthHash.new(provider: nil, uid: nil)
+      get provider
+    end
+
+    it 'redirects to registration' do
+      expect(response).to redirect_to new_user_registration_path
+    end
+  end
+end
+
+describe OmniauthCallbacksController do
+  [:facebook, :twitter].each do |provider|
+    describe "GET ##{provider}" do
+      include_examples :oauth_callback do
+        let(:provider) { provider }
+      end
+    end
+  end
+end
diff --git a/spec/factories/identities.rb b/spec/factories/identities.rb
new file mode 100644
index 0000000..9da8a38
--- /dev/null
+++ b/spec/factories/identities.rb
@@ -0,0 +1,21 @@
+FactoryGirl.define do
+  sequence :uid do |n|
+    "#{Time.now.to_i}-#{Faker::Lorem.word}-#{n}"
+  end
+
+  sequence :provider do |n|
+    "deeprec-provider-#{n}"
+  end
+
+  factory :identity do
+    user
+    provider
+    uid
+  end
+
+  factory :invalid_identity, class: 'Identity' do
+    user nil
+    provider nil
+    uid nil
+  end
+end
diff --git a/spec/features/confirm_oauth_registration_spec.rb b/spec/features/confirm_oauth_registration_spec.rb
new file mode 100644
index 0000000..708a85e
--- /dev/null
+++ b/spec/features/confirm_oauth_registration_spec.rb
@@ -0,0 +1,43 @@
+require 'features_helper'
+
+shared_examples :oauth_registration_confirm do
+  let(:email) { '1234@ab536356c.com' }
+
+  background do
+    clear_emails
+    mock_auth_hash(provider, info: nil)
+    visit new_user_session_path
+    click_on "Sign in with #{provider.to_s.capitalize}"
+    sleep 1
+    fill_in 'Email', with: email
+    click_on "Validate Email"
+    sleep 1
+    save_and_open_page
+    puts '--------------------------------'
+    p ActionMailer::Base.deliveries
+    p all_emails
+    p current_email
+    open_email "test@example.com"
+  end
+
+  # scenario 'check email' do
+  #   current_email.click_link 'Confirm my account'
+  #   expect(page).to have_content 'Your email address has been successfully confirmed'
+  # end
+end
+
+feature 'Confirm OAuth registration', %q(
+  To became regular user
+  As a guest having Facebook or Twitter account
+  I want to set and confirm my email
+) do
+
+  [:facebook, :twitter].each do |prov|
+    context "Logging in with #{prov.to_s.capitalize} OAuth" do
+      given!(:provider) { prov }
+      # given!(:identity) { create(:identity, provider: provider) }
+
+      it_behaves_like :oauth_registration_confirm
+    end
+  end
+end
diff --git a/spec/features/devise_email_spec.rb b/spec/features/devise_email_spec.rb
new file mode 100644
index 0000000..20ec06a
--- /dev/null
+++ b/spec/features/devise_email_spec.rb
@@ -0,0 +1,26 @@
+require 'features_helper'
+
+feature 'Check devise confirmation emails works' do
+  background do
+    # will clear the message queue
+    clear_emails
+    p Devise::Mailer.logger
+    p Devise::Mailer.perform_deliveries
+    p Devise::Mailer.delivery_method
+
+    User.create(email: 'test@example.com', password: '123456')
+    # Will find an email sent to test@example.com
+    # and set `current_email`
+    sleep 1
+    p ActionMailer::Base.deliveries
+    p all_emails
+    open_email('test@example.com')
+    p current_email
+  end
+
+  scenario 'following a link' do
+    p all_emails
+    # current_email.click_link 'your profile'
+    # expect(page).to have_content 'Profile page'
+  end
+end
diff --git a/spec/features/sign_in_oauth_spec.rb b/spec/features/sign_in_oauth_spec.rb
new file mode 100644
index 0000000..0d539bd
--- /dev/null
+++ b/spec/features/sign_in_oauth_spec.rb
@@ -0,0 +1,118 @@
+require 'features_helper'
+
+shared_examples :oauth_sign_in do
+  given(:user) { create(:user) }
+  given(:provider_name) { provider.to_s.capitalize }
+
+  let(:link_text) { "Sign in with #{provider_name}" }
+  let(:success_auth_text) { "GLYPH:info-sign Successfully authenticated from #{provider_name} account." }
+
+  subject(:sign_in_with_oauth) do
+    visit new_user_session_path
+    expect(page).to have_link link_text
+    click_link link_text
+  end
+
+  context 'when email is sent by OAuth provider' do
+    scenario 'when User and Identity are new' do
+      mock_auth_hash(provider, {info: {email: user.email}})
+      sign_in_with_oauth
+
+      expect(page).to have_content success_auth_text
+    end
+
+    scenario 'when User with given email is already registered' do
+      mock_auth_hash(identity.provider, info: {email: user.email})
+      sign_in_with_oauth
+
+      expect(page).to have_content success_auth_text
+      expect(page).not_to have_content 'Enter your email to proceed'
+    end
+
+    scenario 'when Identity is already registered with given email' do
+      mock_auth_hash(identity.provider, uid: identity.uid, info: {email: identity.user.email})
+      sign_in_with_oauth
+
+      expect(page).to have_content success_auth_text
+    end
+  end
+
+  context 'when no email is sent by OAuth provider' do
+    context 'when User and Identity are new' do
+      before do
+        mock_auth_hash(provider, info: nil)
+        sign_in_with_oauth
+
+        expect(page).not_to have_content success_auth_text
+        expect(page).to have_content 'Enter your email to proceed'
+        expect(page).to have_button 'Validate Email'
+      end
+
+      scenario 'with new valid email' do
+        fill_in 'Email', with: generate(:email)
+        click_on 'Validate Email'
+
+        expect(page).to have_content success_auth_text
+      end
+
+      scenario 'with email that already exists' do
+        fill_in 'Email', with: user.email
+        click_on 'Validate Email'
+
+        expect(page).not_to have_content success_auth_text
+        expect(page).to have_content 'GLYPH:alert Email already taken'
+      end
+
+      scenario 'with empty email' do
+        click_on 'Validate Email'
+
+        expect(page).not_to have_content success_auth_text
+        expect(page).to have_content 'Form has an error(s)'
+        expect(page).to have_content 'Email can\'t be blank'
+      end
+
+      scenario 'with invalid email' do
+        fill_in 'Email', with: 'this_is_really_not_an_email'
+        click_on 'Validate Email'
+
+        expect(page).not_to have_content success_auth_text
+        expect(page).to have_content 'Form has an error(s)'
+        expect(page).to have_content 'Email is invalid'
+      end
+    end
+  end
+
+  scenario 'with invalid credentials' do
+    OmniAuth.config.mock_auth[provider] = :invalid_credentials
+    sign_in_with_oauth
+
+    expect(page).not_to have_content success_auth_text
+    expect(page).to have_content 'GLYPH:alert Authentication failure'
+  end
+
+  scenario 'when User already logged in' do
+    sign_in user
+
+    visit new_user_session_path
+
+    expect(page).not_to have_content success_auth_text
+    expect(page).not_to have_link link_text
+    expect(page).to have_content 'GLYPH:alert You are already signed in.'
+  end
+end
+
+feature 'Signing in using OAuth', %q(
+  To ask questions
+  As a user
+  I want to sign in using Facebook or Twitter
+) do
+
+  [:facebook, :twitter].each do |prov|
+    context "Logging in with #{prov.to_s.capitalize} OAuth" do
+      given!(:provider) { prov }
+      given!(:identity) { create(:identity, provider: provider) }
+
+      it_behaves_like :oauth_sign_in
+    end
+  end
+end
diff --git a/spec/features_helper.rb b/spec/features_helper.rb
index 1302751..5fada1b 100644
--- a/spec/features_helper.rb
+++ b/spec/features_helper.rb
@@ -2,6 +2,8 @@
 require 'tilt/coffee'
 
 RSpec.configure do |config|
+  config.include(OmniauthMacros)
+
   Capybara.javascript_driver = :webkit
   Capybara.default_max_wait_time = 10
 
@@ -9,6 +11,9 @@
     config.block_unknown_urls
   end
 
+  Capybara.server_port = 3001
+  Capybara.app_host = 'http://localhost:3001'
+
   config.include FeaturesMacros, type: :feature
 
   config.use_transactional_fixtures = false
@@ -33,3 +38,5 @@
     DatabaseCleaner.clean
   end
 end
+
+OmniAuth.config.test_mode = true
diff --git a/spec/models/identity_spec.rb b/spec/models/identity_spec.rb
new file mode 100644
index 0000000..e065c24
--- /dev/null
+++ b/spec/models/identity_spec.rb
@@ -0,0 +1,14 @@
+require 'rails_helper'
+
+describe Identity do
+  it { is_expected.to belong_to :user }
+
+  it { is_expected.to validate_presence_of :user_id }
+  it { is_expected.to validate_presence_of :uid }
+  it { is_expected.to validate_presence_of :provider }
+
+  describe 'should validate uniqueness of uid for the provider' do
+    subject { create(:identity) }
+    it { is_expected.to validate_uniqueness_of(:uid).scoped_to(:provider) }
+  end
+end
diff --git a/spec/models/user_spec.rb b/spec/models/user_spec.rb
index 25718f3..4da733a 100644
--- a/spec/models/user_spec.rb
+++ b/spec/models/user_spec.rb
@@ -1,9 +1,79 @@
 require 'rails_helper'
 
 RSpec.describe User do
+  it { is_expected.to have_many(:identities).dependent(:destroy) }
   it { is_expected.to have_many(:questions).dependent(:destroy) }
   it { is_expected.to have_many(:answers).dependent(:destroy) }
+  it { is_expected.to have_many(:comments).dependent(:destroy) }
 
   it { is_expected.to validate_presence_of :email }
   it { is_expected.to validate_presence_of :password }
+
+  describe '.find_for_oauth' do
+    let!(:user) { create(:user) }
+    let(:auth) { OmniAuth::AuthHash.new(provider: 'facebook', uid: '42') }
+
+    context 'User\'s Identity already exists' do
+      it 'returns valid user' do
+        user.identities.create(provider: 'facebook', uid: '42')
+        expect(User.find_for_oauth(auth)).to eq user
+      end
+    end
+
+    context 'User\'s Identity doesn\'t exists' do
+      context 'User elready exists' do
+        let(:auth) { OmniAuth::AuthHash.new(provider: 'facebook', uid: '42',
+            info: {email: user.email}) }
+
+        it 'doesn\'t create new User' do
+          expect { User.find_for_oauth(auth) }.to_not change(User, :count)
+        end
+
+        it 'creates Identity for the User' do
+          expect { User.find_for_oauth(auth) }.to change(user.identities, :count).by(1)
+        end
+
+        it 'creates Identity with provider and uid' do
+          identity = User.find_for_oauth(auth).identities.first
+
+          expect(identity.provider).to eq auth.provider
+          expect(identity.uid).to eq auth.uid
+        end
+
+        it 'returns User object' do
+          expect(User.find_for_oauth(auth)).to eq user
+        end
+      end
+
+      context 'User doesn\'t exists' do
+        let(:auth) { OmniAuth::AuthHash.new(provider: 'facebook', uid: '42',
+            info: {email: 'notexistent@user.com'}) }
+
+        it 'creates new User' do
+          expect { User.find_for_oauth(auth) }.to change(User, :count).by(1)
+        end
+
+        it 'returns new User' do
+          expect(User.find_for_oauth(auth)).to be_a(User)
+        end
+
+        it 'fills User\'s email' do
+          user = User.find_for_oauth(auth)
+          expect(user.email).to eq auth.info.email
+        end
+
+        it 'creates Identity for the User' do
+          user = User.find_for_oauth(auth)
+          expect(user.identities).to_not be_empty
+        end
+
+        it 'creates Identity with provider and uid' do
+          identity = User.find_for_oauth(auth).identities.first
+
+          expect(identity.provider).to eq auth.provider
+          expect(identity.uid).to eq auth.uid
+        end
+      end
+    end
+  end
 end
diff --git a/spec/rails_helper.rb b/spec/rails_helper.rb
index 8358237..bf5e6b8 100644
--- a/spec/rails_helper.rb
+++ b/spec/rails_helper.rb
@@ -6,6 +6,7 @@
 require 'spec_helper'
 require 'rspec/rails'
 # Add additional requires below this line. Rails is not loaded until this point!
+require 'capybara/email/rspec'
 
 # Requires supporting ruby files with custom matchers and macros, etc, in
 # spec/support/ and its subdirectories. Files matching `spec/**/*_spec.rb` are
diff --git a/spec/support/omniauth_macros.rb b/spec/support/omniauth_macros.rb
new file mode 100644
index 0000000..056fc9a
--- /dev/null
+++ b/spec/support/omniauth_macros.rb
@@ -0,0 +1,9 @@
+module OmniauthMacros
+  def mock_auth_hash(provider, oauth_params = {})
+    OmniAuth.config.mock_auth[provider] = OmniAuth::AuthHash.new(
+        {
+            provider: provider,
+            uid: '123545'
+        }.merge oauth_params)
+  end
+end