From 5ca23026b9bdeef12145b408f33d85acf1e1311a Mon Sep 17 00:00:00 2001
From: Josh Ellithorpe <quest@mac.com>
Date: Mon, 29 May 2017 23:15:19 -0700
Subject: [PATCH] Rubocop refactor and general cleanup

---
 .rubocop.yml                                  |  18 ++
 CHANGELOG.md                                  |   9 +-
 Gemfile                                       |   7 +-
 README.md                                     | 128 ++++----
 Rakefile                                      |   5 +-
 examples/Gemfile                              |   6 +-
 examples/config.ru                            |  29 +-
 examples/omni_auth.rb                         |  28 +-
 lib/omniauth-google-oauth2.rb                 |   2 +
 lib/omniauth/google_oauth2.rb                 |   2 +
 lib/omniauth/google_oauth2/version.rb         |   4 +-
 lib/omniauth/strategies/google_oauth2.rb      | 108 +++----
 omniauth-google-oauth2.gemspec                |  28 +-
 .../omniauth/strategies/google_oauth2_spec.rb | 282 ++++++++++--------
 spec/rubocop_spec.rb                          |   9 +
 spec/spec_helper.rb                           |   4 +-
 16 files changed, 374 insertions(+), 295 deletions(-)
 create mode 100644 .rubocop.yml
 create mode 100644 spec/rubocop_spec.rb

diff --git a/.rubocop.yml b/.rubocop.yml
new file mode 100644
index 0000000..b2bc16f
--- /dev/null
+++ b/.rubocop.yml
@@ -0,0 +1,18 @@
+ClassLength:
+  Enabled: false
+Layout/IndentHeredoc:
+  Enabled: false
+Metrics/AbcSize:
+  Enabled: false
+Metrics/BlockLength:
+  ExcludedMethods: ['describe', 'context']
+Metrics/CyclomaticComplexity:
+  Enabled: false
+Metrics/LineLength:
+  Enabled: false
+Metrics/MethodLength:
+  Enabled: false
+Metrics/PerceivedComplexity:
+  Enabled: false
+Style/FileName:
+  Enabled: false
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 2f3ec9b..0979b98 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,19 +1,22 @@
 # Changelog
 All notable changes to this project will be documented in this file.
 
-## 0.5.0 - 2017-02-13
+## 0.5.0 - 2017-05-29
 
 ### Added
-- Nothing.
+- Rubocop checks to specs.
+- Defaulted dev environment to ruby 2.3.4.
 
 ### Deprecated
 - Nothing.
 
 ### Removed
 - Testing support for older versions of ruby not supported by OmniAuth 1.5.
+- Key `[:urls]['Google']` no longer exists, it has been renamed to `[:urls][:google]`.
 
 ### Fixed
-- Nothing.
+- Updated all code to rubocop conventions. This includes the Ruby 1.9 hash syntax when appropriate.
+- Example javascript flow now picks up ENV vars for google key and secret.
 
 ## 0.4.1 - 2016-03-14
 
diff --git a/Gemfile b/Gemfile
index bbb7613..7f4f5e9 100644
--- a/Gemfile
+++ b/Gemfile
@@ -1,8 +1,5 @@
+# frozen_string_literal: true
+
 source 'https://rubygems.org'
 
 gemspec
-
-group :example do
-  gem 'sinatra'
-  gem 'rack', '~> 1.6.0'
-end
diff --git a/README.md b/README.md
index 69a1d91..37acbe7 100644
--- a/README.md
+++ b/README.md
@@ -16,7 +16,7 @@ For more details, read the Google docs: https://developers.google.com/accounts/d
 Add to your `Gemfile`:
 
 ```ruby
-gem "omniauth-google-oauth2"
+gem 'omniauth-google-oauth2'
 ```
 
 Then `bundle install`.
@@ -36,7 +36,7 @@ Here's an example for adding the middleware to a Rails app in `config/initialize
 
 ```ruby
 Rails.application.config.middleware.use OmniAuth::Builder do
-  provider :google_oauth2, ENV["GOOGLE_CLIENT_ID"], ENV["GOOGLE_CLIENT_SECRET"]
+  provider :google_oauth2, ENV['GOOGLE_CLIENT_ID'], ENV['GOOGLE_CLIENT_SECRET']
 end
 ```
 
@@ -91,66 +91,69 @@ Here's an example of a possible configuration where the strategy name is changed
 
 ```ruby
 Rails.application.config.middleware.use OmniAuth::Builder do
-  provider :google_oauth2, ENV["GOOGLE_CLIENT_ID"], ENV["GOOGLE_CLIENT_SECRET"],
+  provider :google_oauth2, ENV['GOOGLE_CLIENT_ID'], ENV['GOOGLE_CLIENT_SECRET'],
     {
-      :name => "google",
-      :scope => "email, profile, plus.me, http://gdata.youtube.com",
-      :prompt => "select_account",
-      :image_aspect_ratio => "square",
-      :image_size => 50
+      name: 'google',
+      scope: 'email, profile, plus.me, http://gdata.youtube.com',
+      prompt: 'select_account',
+      image_aspect_ratio: 'square',
+      image_size: 50
     }
 end
 ```
 
 ## Auth Hash
 
-Here's an example of an authentication hash available in the callback by accessing `request.env["omniauth.auth"]`:
+Here's an example of an authentication hash available in the callback by accessing `request.env['omniauth.auth']`:
 
 ```ruby
 {
-    :provider => "google_oauth2",
-    :uid => "123456789",
-    :info => {
-        :name => "John Doe",
-        :email => "john@company_name.com",
-        :first_name => "John",
-        :last_name => "Doe",
-        :image => "https://lh3.googleusercontent.com/url/photo.jpg"
-    },
-    :credentials => {
-        :token => "token",
-        :refresh_token => "another_token",
-        :expires_at => 1354920555,
-        :expires => true
+  "provider" => "google_oauth2",
+  "uid" => "100000000000000000000",
+  "info" => {
+    "name" => "John Smith",
+    "email" => "john@example.com",
+    "first_name" => "John",
+    "last_name" => "Smith",
+    "image" => "https://lh4.googleusercontent.com/photo.jpg",
+    "urls" => {
+      "google" => "https://plus.google.com/+JohnSmith"
+    }
+  },
+  "credentials" => {
+    "token" => "TOKEN",
+    "refresh_token" => "REFRESH_TOKEN",
+    "expires_at" => 1496120719,
+    "expires" => true
+  },
+  "extra" => {
+    "id_token" => "ID_TOKEN",
+    "id_info" => {
+      "azp" => "APP_ID",
+      "aud" => "APP_ID",
+      "sub" => "100000000000000000000",
+      "email" => "john@example.com",
+      "email_verified" => true,
+      "at_hash" => "HK6E_P6Dh8Y93mRNtsDB1Q",
+      "iss" => "accounts.google.com",
+      "iat" => 1496117119,
+      "exp" => 1496120719
     },
-    :extra => {
-        :raw_info => {
-            :sub => "123456789",
-            :email => "user@domain.example.com",
-            :email_verified => true,
-            :name => "John Doe",
-            :given_name => "John",
-            :family_name => "Doe",
-            :profile => "https://plus.google.com/123456789",
-            :picture => "https://lh3.googleusercontent.com/url/photo.jpg",
-            :gender => "male",
-            :birthday => "0000-06-25",
-            :locale => "en",
-            :hd => "company_name.com"
-        },
-        :id_info => {
-            "iss" => "accounts.google.com",
-            "at_hash" => "HK6E_P6Dh8Y93mRNtsDB1Q",
-            "email_verified" => "true",
-            "sub" => "10769150350006150715113082367",
-            "azp" => "APP_ID",
-            "email" => "jsmith@example.com",
-            "aud" => "APP_ID",
-            "iat" => 1353601026,
-            "exp" => 1353604926,
-            "openid_id" => "https://www.google.com/accounts/o8/id?id=ABCdfdswawerSDFDsfdsfdfjdsf"
-        }
+    "raw_info" => {
+      "kind" => "plus#personOpenIdConnect",
+      "gender" => "male",
+      "sub" => "100000000000000000000",
+      "name" => "John Smith",
+      "given_name" => "John",
+      "family_name" => "Smith",
+      "profile" => "https://plus.google.com/+JohnSmith",
+      "picture" => "https://lh4.googleusercontent.com/photo.jpg?sz=50",
+      "email" => "john@example.com",
+      "email_verified" => "true",
+      "locale" => "en",
+      "hd" => "company.com"
     }
+  }
 }
 ```
 
@@ -161,19 +164,19 @@ First define your application id and secret in `config/initializers/devise.rb`.
 Configuration options can be passed as the last parameter here as key/value pairs.
 
 ```ruby
-config.omniauth :google_oauth2, "GOOGLE_CLIENT_ID", "GOOGLE_CLIENT_SECRET", { }
+config.omniauth :google_oauth2, 'GOOGLE_CLIENT_ID', 'GOOGLE_CLIENT_SECRET', {}
 ```
 
 Then add the following to 'config/routes.rb' so the callback routes are defined.
 
 ```ruby
-devise_for :users, :controllers => { :omniauth_callbacks => "users/omniauth_callbacks" }
+devise_for :users, controllers: { omniauth_callbacks: 'users/omniauth_callbacks' }
 ```
 
 Make sure your model is omniauthable. Generally this is "/app/models/user.rb"
 
 ```ruby
-devise :omniauthable, :omniauth_providers => [:google_oauth2]
+devise :omniauthable, omniauth_providers: [:google_oauth2]
 ```
 
 Then make sure your callbacks controller is setup.
@@ -182,13 +185,13 @@ Then make sure your callbacks controller is setup.
 class Users::OmniauthCallbacksController < Devise::OmniauthCallbacksController
   def google_oauth2
       # You need to implement the method below in your model (e.g. app/models/user.rb)
-      @user = User.from_omniauth(request.env["omniauth.auth"])
+      @user = User.from_omniauth(request.env['omniauth.auth'])
 
       if @user.persisted?
-        flash[:notice] = I18n.t "devise.omniauth_callbacks.success", :kind => "Google"
-        sign_in_and_redirect @user, :event => :authentication
+        flash[:notice] = I18n.t 'devise.omniauth_callbacks.success', kind: 'Google'
+        sign_in_and_redirect @user, event: :authentication
       else
-        session["devise.google_data"] = request.env["omniauth.auth"].except(:extra) #Removing extra as it can overflow some session stores
+        session['devise.google_data'] = request.env['omniauth.auth'].except(:extra) #Removing extra as it can overflow some session stores
         redirect_to new_user_registration_url, alert: @user.errors.full_messages.join("\n")
       end
   end
@@ -200,12 +203,12 @@ and bind to or create the user
 ```ruby
 def self.from_omniauth(access_token)
     data = access_token.info
-    user = User.where(:email => data["email"]).first
+    user = User.where(email: data['email']).first
 
     # Uncomment the section below if you want users to be created if they don't exist
     # unless user
-    #     user = User.create(name: data["name"],
-    #        email: data["email"],
+    #     user = User.create(name: data['name'],
+    #        email: data['email'],
     #        password: Devise.friendly_token[0,20]
     #     )
     # end
@@ -269,8 +272,7 @@ window.gpAsyncInit = function() {
     }, function(response) {
       if (response && !response.error) {
         // google authentication succeed, now post data to server.
-        jQuery.ajax({type: 'POST', url: "/auth/google_oauth2/callback", 
-data: response,
+        jQuery.ajax({type: 'POST', url: '/auth/google_oauth2/callback', data: response,
           success: function(data) {
             // response from server
           }
@@ -305,7 +307,7 @@ OmniAuth.config.full_host = Rails.env.production? ? 'https://domain.com' : 'http
 
 ## License
 
-Copyright (c) 2016 by Josh Ellithorpe
+Copyright (c) 2017 by Josh Ellithorpe
 
 Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
 
diff --git a/Rakefile b/Rakefile
index 591ff85..db36369 100644
--- a/Rakefile
+++ b/Rakefile
@@ -1,7 +1,8 @@
-#!/usr/bin/env rake
+# frozen_string_literal: true
+
 require File.join('bundler', 'gem_tasks')
 require File.join('rspec', 'core', 'rake_task')
 
 RSpec::Core::RakeTask.new(:spec)
 
-task :default => :spec
\ No newline at end of file
+task default: :spec
diff --git a/examples/Gemfile b/examples/Gemfile
index 07708ae..5dcbf09 100644
--- a/examples/Gemfile
+++ b/examples/Gemfile
@@ -1,4 +1,6 @@
+# frozen_string_literal: true
+
 source 'https://rubygems.org'
 
-gem 'sinatra'
-gem 'omniauth-google-oauth2'
+gem 'omniauth-google-oauth2', '~> 0.5'
+gem 'sinatra', '~> 1.4'
diff --git a/examples/config.ru b/examples/config.ru
index 1931f9e..a09d307 100644
--- a/examples/config.ru
+++ b/examples/config.ru
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 # Sample app for Google OAuth2 Strategy
 # Make sure to setup the ENV variables GOOGLE_KEY and GOOGLE_SECRET
 # Run with "bundle exec rackup"
@@ -15,6 +17,7 @@ require 'omniauth-google-oauth2'
 # http://railsapps.github.io/openssl-certificate-verify-failed.html
 OpenSSL::SSL::VERIFY_PEER = OpenSSL::SSL::VERIFY_NONE
 
+# Main example app for omniauth-google-oauth2
 class App < Sinatra::Base
   get '/' do
     <<-HTML
@@ -37,7 +40,7 @@ class App < Sinatra::Base
           immediate: true,
           response_type: 'code',
           cookie_policy: 'single_host_origin',
-          client_id: 'YOUR_CLIENT_ID',
+          client_id: '#{ENV['GOOGLE_KEY']}',
           scope: 'email profile'
         }, function(response) {
           return;
@@ -48,7 +51,7 @@ class App < Sinatra::Base
             immediate: false,
             response_type: 'code',
             cookie_policy: 'single_host_origin',
-            client_id: 'YOUR_CLIENT_ID',
+            client_id: '#{ENV['GOOGLE_KEY']}',
             scope: 'email profile'
           }, function(response) {
             if (response && !response.error) {
@@ -80,26 +83,38 @@ class App < Sinatra::Base
 
   post '/auth/:provider/callback' do
     content_type 'text/plain'
-    request.env['omniauth.auth'].to_hash.inspect rescue "No Data"
+    begin
+      request.env['omniauth.auth'].to_hash.inspect
+    rescue
+      'No Data'
+    end
   end
 
   get '/auth/:provider/callback' do
     content_type 'text/plain'
-    request.env['omniauth.auth'].to_hash.inspect rescue "No Data"
+    begin
+      request.env['omniauth.auth'].to_hash.inspect
+    rescue
+      'No Data'
+    end
   end
 
   get '/auth/failure' do
     content_type 'text/plain'
-    request.env['omniauth.auth'].to_hash.inspect rescue "No Data"
+    begin
+      request.env['omniauth.auth'].to_hash.inspect
+    rescue
+      'No Data'
+    end
   end
 end
 
-use Rack::Session::Cookie, :secret => ENV['RACK_COOKIE_SECRET']
+use Rack::Session::Cookie, secret: ENV['RACK_COOKIE_SECRET']
 
 use OmniAuth::Builder do
   # For additional provider examples please look at 'omni_auth.rb'
   # The key provider_ignores_state is only for AJAX flows. It is not recommended for normal logins.
-  provider :google_oauth2, ENV['GOOGLE_KEY'], ENV['GOOGLE_SECRET'], {access_type: "offline", prompt: "consent", provider_ignores_state: true, scope: 'email,profile,calendar'}
+  provider :google_oauth2, ENV['GOOGLE_KEY'], ENV['GOOGLE_SECRET'], access_type: 'offline', prompt: 'consent', provider_ignores_state: true, scope: 'email,profile,calendar'
 end
 
 run App.new
diff --git a/examples/omni_auth.rb b/examples/omni_auth.rb
index be65fa9..127b62a 100644
--- a/examples/omni_auth.rb
+++ b/examples/omni_auth.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 # Google's OAuth2 docs. Make sure you are familiar with all the options
 # before attempting to configure this gem.
 # https://developers.google.com/accounts/docs/OAuth2Login
@@ -6,40 +8,26 @@
   # Default usage, this will give you offline access and a refresh token
   # using default scopes 'email' and 'profile'
   #
-  provider :google_oauth2, ENV['GOOGLE_KEY'], ENV['GOOGLE_SECRET'], {
-    :scope => 'email,profile'
-  }
+  provider :google_oauth2, ENV['GOOGLE_KEY'], ENV['GOOGLE_SECRET'], scope: 'email,profile'
 
   # Manual setup for offline access with a refresh token.
   #
-  # provider :google_oauth2, ENV['GOOGLE_KEY'], ENV['GOOGLE_SECRET'], {
-  #   :access_type => 'offline',
-  # }
+  # provider :google_oauth2, ENV['GOOGLE_KEY'], ENV['GOOGLE_SECRET'], access_type: 'offline'
 
   # Custom scope supporting youtube. If you are customizing scopes, remember
   # to include the default scopes 'email' and 'profile'
   #
-  # provider :google_oauth2, ENV['GOOGLE_KEY'], ENV['GOOGLE_SECRET'], {
-  #   :scope => 'http://gdata.youtube.com,email,profile,plus.me'
-  # }
+  # provider :google_oauth2, ENV['GOOGLE_KEY'], ENV['GOOGLE_SECRET'], scope: 'http://gdata.youtube.com,email,profile,plus.me'
 
   # Custom scope for users only using Google for account creation/auth and do not require a refresh token.
   #
-  # provider :google_oauth2, ENV['GOOGLE_KEY'], ENV['GOOGLE_SECRET'], {
-  #   :access_type => 'online',
-  #   :prompt => ''
-  # }
+  # provider :google_oauth2, ENV['GOOGLE_KEY'], ENV['GOOGLE_SECRET'], access_type: 'online', prompt: ''
 
   # To include information about people in your circles you must include the 'plus.login' scope.
   #
-  # provider :google_oauth2, ENV['GOOGLE_KEY'], ENV['GOOGLE_SECRET'], {
-  #   :skip_friends => false,
-  #   :scope => "email,profile,plus.login"
-  # }
+  # provider :google_oauth2, ENV['GOOGLE_KEY'], ENV['GOOGLE_SECRET'], skip_friends: false, scope: 'email,profile,plus.login'
 
   # If you need to acquire whether user picture is a default one or uploaded by user.
   #
-  # provider :google_oauth2, ENV['GOOGLE_KEY'], ENV['GOOGLE_SECRET'], {
-  #   :skip_image_info => false
-  # }
+  # provider :google_oauth2, ENV['GOOGLE_KEY'], ENV['GOOGLE_SECRET'], skip_image_info: false
 end
diff --git a/lib/omniauth-google-oauth2.rb b/lib/omniauth-google-oauth2.rb
index 88ca8ca..a5cc57a 100644
--- a/lib/omniauth-google-oauth2.rb
+++ b/lib/omniauth-google-oauth2.rb
@@ -1 +1,3 @@
+# frozen_string_literal: true
+
 require 'omniauth/google_oauth2'
diff --git a/lib/omniauth/google_oauth2.rb b/lib/omniauth/google_oauth2.rb
index 067a579..594c9a4 100644
--- a/lib/omniauth/google_oauth2.rb
+++ b/lib/omniauth/google_oauth2.rb
@@ -1 +1,3 @@
+# frozen_string_literal: true
+
 require 'omniauth/strategies/google_oauth2'
diff --git a/lib/omniauth/google_oauth2/version.rb b/lib/omniauth/google_oauth2/version.rb
index e690c7b..91d41d0 100644
--- a/lib/omniauth/google_oauth2/version.rb
+++ b/lib/omniauth/google_oauth2/version.rb
@@ -1,5 +1,7 @@
+# frozen_string_literal: true
+
 module OmniAuth
   module GoogleOauth2
-    VERSION = "0.5.0"
+    VERSION = '0.5.0'
   end
 end
diff --git a/lib/omniauth/strategies/google_oauth2.rb b/lib/omniauth/strategies/google_oauth2.rb
index d2a33e1..9d183b3 100644
--- a/lib/omniauth/strategies/google_oauth2.rb
+++ b/lib/omniauth/strategies/google_oauth2.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'multi_json'
 require 'jwt'
 require 'omniauth/strategies/oauth2'
@@ -5,24 +7,24 @@
 
 module OmniAuth
   module Strategies
+    # Main class for Google OAuth2 strategy.
     class GoogleOauth2 < OmniAuth::Strategies::OAuth2
-      BASE_SCOPE_URL = "https://www.googleapis.com/auth/"
-      BASE_SCOPES = %w[profile email openid]
-      DEFAULT_SCOPE = "email,profile"
+      BASE_SCOPE_URL = 'https://www.googleapis.com/auth/'
+      BASE_SCOPES = %w[profile email openid].freeze
+      DEFAULT_SCOPE = 'email,profile'
 
       option :name, 'google_oauth2'
       option :skip_friends, true
       option :skip_image_info, true
       option :skip_jwt, false
       option :jwt_leeway, 60
-      option :authorize_options, [:access_type, :hd, :login_hint, :prompt, :request_visible_actions, :scope, :state, :redirect_uri, :include_granted_scopes, :openid_realm]
+      option :authorize_options, %i[access_type hd login_hint prompt request_visible_actions scope state redirect_uri include_granted_scopes openid_realm]
       option :authorized_client_ids, []
 
-      option :client_options, {
-        :site          => 'https://accounts.google.com',
-        :authorize_url => '/o/oauth2/auth',
-        :token_url     => '/o/oauth2/token'
-      }
+      option :client_options,
+             site: 'https://accounts.google.com',
+             authorize_url: '/o/oauth2/auth',
+             token_url: '/o/oauth2/token'
 
       def authorize_params
         super.tap do |params|
@@ -30,30 +32,27 @@ def authorize_params
             params[k] = request.params[k.to_s] unless [nil, ''].include?(request.params[k.to_s])
           end
 
-          raw_scope = params[:scope] || DEFAULT_SCOPE
-          scope_list = raw_scope.split(" ").map {|item| item.split(",")}.flatten
-          scope_list.map! { |s| s =~ /^https?:\/\// || BASE_SCOPES.include?(s) ? s : "#{BASE_SCOPE_URL}#{s}" }
-          params[:scope] = scope_list.join(" ")
+          params[:scope] = get_scope(params)
           params[:access_type] = 'offline' if params[:access_type].nil?
           params['openid.realm'] = params.delete(:openid_realm) unless params[:openid_realm].nil?
 
-          session['omniauth.state'] = params[:state] if params['state']
+          session['omniauth.state'] = params[:state] if params[:state]
         end
       end
 
       uid { raw_info['sub'] }
 
       info do
-        prune!({
-          :name       => raw_info['name'],
-          :email      => verified_email,
-          :first_name => raw_info['given_name'],
-          :last_name  => raw_info['family_name'],
-          :image      => image_url,
-          :urls => {
-            'Google' => raw_info['profile']
+        prune!(
+          name: raw_info['name'],
+          email: verified_email,
+          first_name: raw_info['given_name'],
+          last_name: raw_info['family_name'],
+          image: image_url,
+          urls: {
+            google: raw_info['profile']
           }
-        })
+        )
       end
 
       extra do
@@ -61,18 +60,17 @@ def authorize_params
         hash[:id_token] = access_token['id_token']
         if !options[:skip_jwt] && !access_token['id_token'].nil?
           hash[:id_info] = JWT.decode(
-            access_token['id_token'], nil, false, {
-              :verify_iss => true,
-              'iss' => 'accounts.google.com',
-              :verify_aud => true,
-              'aud' => options.client_id,
-              :verify_sub => false,
-              :verify_expiration => true,
-              :verify_not_before => true,
-              :verify_iat => true,
-              :verify_jti => false,
-              :leeway => options[:jwt_leeway]
-            }).first
+            access_token['id_token'], nil, false, verify_iss: true,
+                                                  iss: 'accounts.google.com',
+                                                  verify_aud: true,
+                                                  aud: options.client_id,
+                                                  verify_sub: false,
+                                                  verify_expiration: true,
+                                                  verify_not_before: true,
+                                                  verify_iat: true,
+                                                  verify_jti: false,
+                                                  leeway: options[:jwt_leeway]
+          ).first
         end
         hash[:raw_info] = raw_info unless skip_info?
         hash[:raw_friend_info] = raw_friend_info(raw_info['sub']) unless skip_info? || options[:skip_friends]
@@ -93,7 +91,20 @@ def raw_image_info(id)
       end
 
       def custom_build_access_token
-        access_token =
+        access_token = get_access_token(request)
+
+        verify_hd(access_token)
+        access_token
+      end
+      alias build_access_token custom_build_access_token
+
+      private
+
+      def callback_url
+        options[:redirect_uri] || (full_host + script_name + callback_path)
+      end
+
+      def get_access_token(request)
         if request.xhr? && request.params['code']
           verifier = request.params['code']
           redirect_uri = request.params['redirect_uri'] || 'postmessage'
@@ -105,23 +116,20 @@ def custom_build_access_token
         elsif verify_token(request.params['access_token'])
           ::OAuth2::AccessToken.from_hash(client, request.params.dup)
         else
-          verifier = request.params["code"]
+          verifier = request.params['code']
           client.auth_code.get_token(verifier, get_token_options(callback_url), deep_symbolize(options.auth_token_params))
         end
-
-        verify_hd(access_token)
-        access_token
       end
-      alias_method :build_access_token, :custom_build_access_token
 
-      private
-
-      def callback_url
-        options[:redirect_uri] || (full_host + script_name + callback_path)
+      def get_scope(params)
+        raw_scope = params[:scope] || DEFAULT_SCOPE
+        scope_list = raw_scope.split(' ').map { |item| item.split(',') }.flatten
+        scope_list.map! { |s| s =~ %r{^https?://} || BASE_SCOPES.include?(s) ? s : "#{BASE_SCOPE_URL}#{s}" }
+        scope_list.join(' ')
       end
 
       def get_token_options(redirect_uri)
-        { :redirect_uri => redirect_uri }.merge(token_params.to_hash(:symbolize_keys => true))
+        { redirect_uri: redirect_uri }.merge(token_params.to_hash(symbolize_keys: true))
       end
 
       def prune!(hash)
@@ -153,7 +161,7 @@ def image_url
       end
 
       def image_size_opts_passed?
-        !!(options[:image_size] || options[:image_aspect_ratio])
+        options[:image_size] || options[:image_aspect_ratio]
       end
 
       def image_params
@@ -174,7 +182,7 @@ def strip_unnecessary_query_parameters(query_parameters)
         return nil if query_parameters.nil?
 
         params = CGI.parse(query_parameters)
-        stripped_params = params.delete_if { |key| key == "sz" }
+        stripped_params = params.delete_if { |key| key == 'sz' }
 
         # don't return an empty Hash since that would result
         # in URLs with a trailing ? character: http://image.url?
@@ -193,11 +201,11 @@ def verify_token(access_token)
       def verify_hd(access_token)
         return true unless options.hd
         @raw_info ||= access_token.get('https://www.googleapis.com/plus/v1/people/me/openIdConnect').parsed
-        
+
         options.hd = options.hd.call if options.hd.is_a? Proc
         allowed_hosted_domains = Array(options.hd)
 
-        raise CallbackError.new(:invalid_hd, "Invalid Hosted Domain") unless allowed_hosted_domains.include? @raw_info['hd']
+        raise CallbackError.new(:invalid_hd, 'Invalid Hosted Domain') unless allowed_hosted_domains.include? @raw_info['hd']
         true
       end
     end
diff --git a/omniauth-google-oauth2.gemspec b/omniauth-google-oauth2.gemspec
index cb829d2..ab36193 100644
--- a/omniauth-google-oauth2.gemspec
+++ b/omniauth-google-oauth2.gemspec
@@ -1,26 +1,32 @@
 # -*- encoding: utf-8 -*-
-require File.expand_path(File.join('..', 'lib', 'omniauth', 'google_oauth2', 'version'), __FILE__)
+# frozen_string_literal: true
+
+require File.expand_path(
+  File.join('..', 'lib', 'omniauth', 'google_oauth2', 'version'),
+  __FILE__
+)
 
 Gem::Specification.new do |gem|
-  gem.name          = "omniauth-google-oauth2"
+  gem.name          = 'omniauth-google-oauth2'
   gem.version       = OmniAuth::GoogleOauth2::VERSION
   gem.license       = 'MIT'
-  gem.summary       = %q{A Google OAuth2 strategy for OmniAuth 1.x}
-  gem.description   = %q{A Google OAuth2 strategy for OmniAuth 1.x}
-  gem.authors       = ["Josh Ellithorpe", "Yury Korolev"]
-  gem.email         = ["quest@mac.com"]
-  gem.homepage      = "https://github.com/zquestz/omniauth-google-oauth2"
+  gem.summary       = %(A Google OAuth2 strategy for OmniAuth 1.x)
+  gem.description   = %(A Google OAuth2 strategy for OmniAuth 1.x. This allows you to login to Google with your ruby app.)
+  gem.authors       = ['Josh Ellithorpe', 'Yury Korolev']
+  gem.email         = ['quest@mac.com']
+  gem.homepage      = 'https://github.com/zquestz/omniauth-google-oauth2'
 
   gem.files         = `git ls-files`.split("\n")
-  gem.require_paths = ["lib"]
+  gem.require_paths = ['lib']
 
   gem.required_ruby_version = '>= 2.0'
 
   gem.add_runtime_dependency 'omniauth', '>= 1.1.1'
   gem.add_runtime_dependency 'omniauth-oauth2', '>= 1.3.1'
-  gem.add_runtime_dependency 'jwt', '~> 1.5.2'
+  gem.add_runtime_dependency 'jwt', '~> 1.5'
   gem.add_runtime_dependency 'multi_json', '~> 1.3'
 
-  gem.add_development_dependency 'rspec', '>= 2.14.0'
-  gem.add_development_dependency 'rake'
+  gem.add_development_dependency 'rspec', '~> 3.6'
+  gem.add_development_dependency 'rake', '~> 12.0'
+  gem.add_development_dependency 'rubocop', '~> 0.49'
 end
diff --git a/spec/omniauth/strategies/google_oauth2_spec.rb b/spec/omniauth/strategies/google_oauth2_spec.rb
index 8b3103c..698ffcc 100644
--- a/spec/omniauth/strategies/google_oauth2_spec.rb
+++ b/spec/omniauth/strategies/google_oauth2_spec.rb
@@ -1,19 +1,21 @@
+# frozen_string_literal: true
+
 require 'spec_helper'
 require 'omniauth-google-oauth2'
 
 describe OmniAuth::Strategies::GoogleOauth2 do
-  let(:request) { double('Request', :params => {}, :cookies => {}, :env => {}) }
-  let(:app) {
+  let(:request) { double('Request', params: {}, cookies: {}, env: {}) }
+  let(:app) do
     lambda do
-      [200, {}, ["Hello."]]
+      [200, {}, ['Hello.']]
     end
-  }
+  end
 
   subject do
     OmniAuth::Strategies::GoogleOauth2.new(app, 'appid', 'secret', @options || {}).tap do |strategy|
-      allow(strategy).to receive(:request) {
+      allow(strategy).to receive(:request) do
         request
-      }
+      end
     end
   end
 
@@ -38,40 +40,59 @@
       expect(subject.client.options[:token_url]).to eq('/o/oauth2/token')
     end
 
-    describe "overrides" do
-      it 'should allow overriding the site' do
-        @options = {:client_options => {'site' => 'https://example.com'}}
-        expect(subject.client.site).to eq('https://example.com')
-      end
+    describe 'overrides' do
+      context 'as strings' do
+        it 'should allow overriding the site' do
+          @options = { client_options: { 'site' => 'https://example.com' } }
+          expect(subject.client.site).to eq('https://example.com')
+        end
 
-      it 'should allow overriding the authorize_url' do
-        @options = {:client_options => {'authorize_url' => 'https://example.com'}}
-        expect(subject.client.options[:authorize_url]).to eq('https://example.com')
+        it 'should allow overriding the authorize_url' do
+          @options = { client_options: { 'authorize_url' => 'https://example.com' } }
+          expect(subject.client.options[:authorize_url]).to eq('https://example.com')
+        end
+
+        it 'should allow overriding the token_url' do
+          @options = { client_options: { 'token_url' => 'https://example.com' } }
+          expect(subject.client.options[:token_url]).to eq('https://example.com')
+        end
       end
 
-      it 'should allow overriding the token_url' do
-        @options = {:client_options => {'token_url' => 'https://example.com'}}
-        expect(subject.client.options[:token_url]).to eq('https://example.com')
+      context 'as symbols' do
+        it 'should allow overriding the site' do
+          @options = { client_options: { site: 'https://example.com' } }
+          expect(subject.client.site).to eq('https://example.com')
+        end
+
+        it 'should allow overriding the authorize_url' do
+          @options = { client_options: { authorize_url: 'https://example.com' } }
+          expect(subject.client.options[:authorize_url]).to eq('https://example.com')
+        end
+
+        it 'should allow overriding the token_url' do
+          @options = { client_options: { token_url: 'https://example.com' } }
+          expect(subject.client.options[:token_url]).to eq('https://example.com')
+        end
       end
     end
   end
 
-  describe "#authorize_options" do
-    [:access_type, :hd, :login_hint, :prompt, :scope, :state].each do |k|
+  describe '#authorize_options' do
+    %i[access_type hd login_hint prompt scope state].each do |k|
       it "should support #{k}" do
-        @options = {k => 'http://someval'}
+        @options = { k => 'http://someval' }
         expect(subject.authorize_params[k.to_s]).to eq('http://someval')
       end
     end
 
-    describe "redirect_uri" do
+    describe 'redirect_uri' do
       it 'should default to nil' do
         @options = {}
         expect(subject.authorize_params['redirect_uri']).to eq(nil)
       end
 
       it 'should set the redirect_uri parameter if present' do
-        @options = {:redirect_uri => 'https://example.com'}
+        @options = { redirect_uri: 'https://example.com' }
         expect(subject.authorize_params['redirect_uri']).to eq('https://example.com')
       end
     end
@@ -83,56 +104,56 @@
       end
 
       it 'should set the access_type parameter if present' do
-        @options = {:access_type => 'online'}
+        @options = { access_type: 'online' }
         expect(subject.authorize_params['access_type']).to eq('online')
       end
     end
 
     describe 'hd' do
-      it "should default to nil" do
+      it 'should default to nil' do
         expect(subject.authorize_params['hd']).to eq(nil)
       end
 
       it 'should set the hd (hosted domain) parameter if present' do
-        @options = {:hd => 'example.com'}
+        @options = { hd: 'example.com' }
         expect(subject.authorize_params['hd']).to eq('example.com')
       end
 
       it 'should set the hd parameter and work with nil hd (gmail)' do
-        @options = {:hd => nil }
+        @options = { hd: nil }
         expect(subject.authorize_params['hd']).to eq(nil)
       end
     end
 
     describe 'login_hint' do
-      it "should default to nil" do
+      it 'should default to nil' do
         expect(subject.authorize_params['login_hint']).to eq(nil)
       end
 
       it 'should set the login_hint parameter if present' do
-        @options = {:login_hint => 'john@example.com'}
+        @options = { login_hint: 'john@example.com' }
         expect(subject.authorize_params['login_hint']).to eq('john@example.com')
       end
     end
 
     describe 'prompt' do
-      it "should default to nil" do
+      it 'should default to nil' do
         expect(subject.authorize_params['prompt']).to eq(nil)
       end
 
       it 'should set the prompt parameter if present' do
-        @options = {:prompt => 'consent select_account'}
+        @options = { prompt: 'consent select_account' }
         expect(subject.authorize_params['prompt']).to eq('consent select_account')
       end
     end
 
     describe 'request_visible_actions' do
-      it "should default to nil" do
+      it 'should default to nil' do
         expect(subject.authorize_params['request_visible_actions']).to eq(nil)
       end
 
       it 'should set the request_visible_actions parameter if present' do
-        @options = {:request_visible_actions => 'something'}
+        @options = { request_visible_actions: 'something' }
         expect(subject.authorize_params['request_visible_actions']).to eq('something')
       end
     end
@@ -143,29 +164,29 @@
       end
 
       it 'should set the include_granted_scopes parameter if present' do
-        @options = {:include_granted_scopes => 'true'}
+        @options = { include_granted_scopes: 'true' }
         expect(subject.authorize_params['include_granted_scopes']).to eq('true')
       end
     end
 
     describe 'scope' do
       it 'should expand scope shortcuts' do
-        @options = {:scope => 'plus.me'}
+        @options = { scope: 'plus.me' }
         expect(subject.authorize_params['scope']).to eq('https://www.googleapis.com/auth/plus.me')
       end
 
       it 'should leave base scopes as is' do
-        @options = {:scope => 'profile'}
+        @options = { scope: 'profile' }
         expect(subject.authorize_params['scope']).to eq('profile')
       end
 
       it 'should join scopes' do
-        @options = {:scope => 'profile,email'}
+        @options = { scope: 'profile,email' }
         expect(subject.authorize_params['scope']).to eq('profile email')
       end
 
       it 'should deal with whitespace when joining scopes' do
-        @options = {:scope => 'profile, email'}
+        @options = { scope: 'profile, email' }
         expect(subject.authorize_params['scope']).to eq('profile email')
       end
 
@@ -174,56 +195,58 @@
       end
 
       it 'should support space delimited scopes' do
-        @options = {:scope => 'profile email'}
+        @options = { scope: 'profile email' }
         expect(subject.authorize_params['scope']).to eq('profile email')
       end
 
-      it "should support extremely badly formed scopes" do
-        @options = {:scope => 'profile email,foo,steve yeah http://example.com'}
+      it 'should support extremely badly formed scopes' do
+        @options = { scope: 'profile email,foo,steve yeah http://example.com' }
         expect(subject.authorize_params['scope']).to eq('profile email https://www.googleapis.com/auth/foo https://www.googleapis.com/auth/steve https://www.googleapis.com/auth/yeah http://example.com')
       end
     end
 
     describe 'state' do
       it 'should set the state parameter' do
-        @options = {:state => 'some_state'}
+        @options = { state: 'some_state' }
         expect(subject.authorize_params['state']).to eq('some_state')
+        expect(subject.authorize_params[:state]).to eq('some_state')
         expect(subject.session['omniauth.state']).to eq('some_state')
       end
 
       it 'should set the omniauth.state dynamically' do
-        allow(subject).to receive(:request) { double('Request', {:params => {'state' => 'some_state'}, :env => {}}) }
+        allow(subject).to receive(:request) { double('Request', params: { 'state' => 'some_state' }, env: {}) }
         expect(subject.authorize_params['state']).to eq('some_state')
+        expect(subject.authorize_params[:state]).to eq('some_state')
         expect(subject.session['omniauth.state']).to eq('some_state')
       end
     end
 
-    describe "overrides" do
+    describe 'overrides' do
       it 'should include top-level options that are marked as :authorize_options' do
-        @options = {:authorize_options => [:scope, :foo, :request_visible_actions], :scope => 'http://bar', :foo => 'baz', :hd => "wow", :request_visible_actions => "something"}
+        @options = { authorize_options: %i[scope foo request_visible_actions], scope: 'http://bar', foo: 'baz', hd: 'wow', request_visible_actions: 'something' }
         expect(subject.authorize_params['scope']).to eq('http://bar')
         expect(subject.authorize_params['foo']).to eq('baz')
         expect(subject.authorize_params['hd']).to eq(nil)
         expect(subject.authorize_params['request_visible_actions']).to eq('something')
       end
 
-      describe "request overrides" do
-        [:access_type, :hd, :login_hint, :prompt, :scope, :state].each do |k|
+      describe 'request overrides' do
+        %i[access_type hd login_hint prompt scope state].each do |k|
           context "authorize option #{k}" do
-            let(:request) { double('Request', :params => {k.to_s => 'http://example.com'}, :cookies => {}, :env => {}) }
+            let(:request) { double('Request', params: { k.to_s => 'http://example.com' }, cookies: {}, env: {}) }
 
             it "should set the #{k} authorize option dynamically in the request" do
-              @options = {k => ''}
+              @options = { k: '' }
               expect(subject.authorize_params[k.to_s]).to eq('http://example.com')
             end
           end
         end
 
-        describe "custom authorize_options" do
-          let(:request) { double('Request', :params => {'foo' => 'something'}, :cookies => {}, :env => {}) }
+        describe 'custom authorize_options' do
+          let(:request) { double('Request', params: { 'foo' => 'something' }, cookies: {}, env: {}) }
 
-          it "should support request overrides from custom authorize_options" do
-            @options = {:authorize_options => [:foo], :foo => ''}
+          it 'should support request overrides from custom authorize_options' do
+            @options = { authorize_options: [:foo], foo: '' }
             expect(subject.authorize_params['foo']).to eq('something')
           end
         end
@@ -233,7 +256,7 @@
 
   describe '#authorize_params' do
     it 'should include any authorize params passed in the :authorize_params option' do
-      @options = {:authorize_params => {:request_visible_actions => 'something', :foo => 'bar', :baz => 'zip'}, :hd => 'wow', :bad => 'not_included'}
+      @options = { authorize_params: { request_visible_actions: 'something', foo: 'bar', baz: 'zip' }, hd: 'wow', bad: 'not_included' }
       expect(subject.authorize_params['request_visible_actions']).to eq('something')
       expect(subject.authorize_params['foo']).to eq('bar')
       expect(subject.authorize_params['baz']).to eq('zip')
@@ -244,15 +267,15 @@
 
   describe '#token_params' do
     it 'should include any token params passed in the :token_params option' do
-      @options = {:token_params => {:foo => 'bar', :baz => 'zip'}}
+      @options = { token_params: { foo: 'bar', baz: 'zip' } }
       expect(subject.token_params['foo']).to eq('bar')
       expect(subject.token_params['baz']).to eq('zip')
     end
   end
 
-  describe "#token_options" do
+  describe '#token_options' do
     it 'should include top-level options that are marked as :token_options' do
-      @options = {:token_options => [:scope, :foo], :scope => 'bar', :foo => 'baz', :bad => 'not_included'}
+      @options = { token_options: %i[scope foo], scope: 'bar', foo: 'baz', bad: 'not_included' }
       expect(subject.token_params['scope']).to eq('bar')
       expect(subject.token_params['foo']).to eq('baz')
       expect(subject.token_params['bad']).to eq(nil)
@@ -265,10 +288,9 @@
     end
 
     it 'should set the callback_path parameter if present' do
-      @options = {:callback_path => '/auth/foo/callback'}
+      @options = { callback_path: '/auth/foo/callback' }
       expect(subject.callback_path).to eq('/auth/foo/callback')
     end
-
   end
 
   describe '#extra' do
@@ -276,9 +298,9 @@
       OAuth2::Client.new('abc', 'def') do |builder|
         builder.request :url_encoded
         builder.adapter :test do |stub|
-          stub.get('/plus/v1/people/me/openIdConnect') {|env| [200, {'content-type' => 'application/json'}, '{"sub": "12345"}']}
-          stub.get('/plus/v1/people/12345/people/visible') {|env| [200, {'content-type' => 'application/json'}, '[{"foo":"bar"}]']}
-          stub.get('/plus/v1/people/12345?fields=image') {|env| [200, {'content-type' => 'application/json'}, '{"image":"imageData"}']}
+          stub.get('/plus/v1/people/me/openIdConnect') { [200, { 'content-type' => 'application/json' }, '{"sub": "12345"}'] }
+          stub.get('/plus/v1/people/12345/people/visible') { [200, { 'content-type' => 'application/json' }, '[{"foo":"bar"}]'] }
+          stub.get('/plus/v1/people/12345?fields=image') { [200, { 'content-type' => 'application/json' }, '{"image":"imageData"}'] }
         end
       end
     end
@@ -295,18 +317,18 @@
             'nbf' => Time.now.to_i - 60,
             'iat' => Time.now.to_i,
             'aud' => 'appid',
-            'iss' => 'accounts.google.com',
+            'iss' => 'accounts.google.com'
           }
         id_token = JWT.encode(token_info, 'secret')
-        let(:access_token) { OAuth2::AccessToken.from_hash(client, {'id_token' => id_token}) }
+        let(:access_token) { OAuth2::AccessToken.from_hash(client, 'id_token' => id_token) }
 
         it 'should include id_token when set on the access_token' do
-          expect(subject.extra).to include(:id_token => id_token)
+          expect(subject.extra).to include(id_token: id_token)
         end
 
         it 'should include id_info when id_token is set on the access_token and skip_jwt is false' do
           subject.options[:skip_jwt] = false
-          expect(subject.extra).to include(:id_info => token_info)
+          expect(subject.extra).to include(id_info: token_info)
         end
 
         it 'should not include id_info when id_token is set on the access_token and skip_jwt is true' do
@@ -315,7 +337,7 @@
         end
 
         it 'should include id_info when id_token is set on the access_token by default' do
-          expect(subject.extra).to include(:id_info => token_info)
+          expect(subject.extra).to include(id_info: token_info)
         end
       end
 
@@ -372,7 +394,7 @@
           before { subject.options[:skip_friends] = false }
 
           it 'should not include raw_friend_info' do
-            expect(subject.extra[:raw_friend_info]).to eq([{'foo' => 'bar'}])
+            expect(subject.extra[:raw_friend_info]).to eq([{ 'foo' => 'bar' }])
           end
         end
       end
@@ -402,7 +424,7 @@
           before { subject.options[:skip_image_info] = false }
 
           it 'should include raw_image_info' do
-            expect(subject.extra[:raw_image_info]).to eq({'image' => 'imageData'})
+            expect(subject.extra[:raw_image_info]).to eq('image' => 'imageData')
           end
         end
       end
@@ -411,92 +433,92 @@
 
   describe 'populate auth hash urls' do
     it 'should populate url map in auth hash if link present in raw_info' do
-      allow(subject).to receive(:raw_info) { {'name' => 'Foo', 'profile' => 'https://plus.google.com/123456'} }
-      expect(subject.info[:urls]['Google']).to eq('https://plus.google.com/123456')
+      allow(subject).to receive(:raw_info) { { 'name' => 'Foo', 'profile' => 'https://plus.google.com/123456' } }
+      expect(subject.info[:urls][:google]).to eq('https://plus.google.com/123456')
     end
 
     it 'should not populate url map in auth hash if no link present in raw_info' do
-      allow(subject).to receive(:raw_info) { {'name' => 'Foo'} }
+      allow(subject).to receive(:raw_info) { { 'name' => 'Foo' } }
       expect(subject.info).not_to have_key(:urls)
     end
   end
 
   describe 'image options' do
-    it "should have no image if a picture isn't present" do
-      @options = {:image_aspect_ratio => 'square'}
-      allow(subject).to receive(:raw_info) { {'name' => 'User Without Pic'} }
+    it 'should have no image if a picture is not present' do
+      @options = { image_aspect_ratio: 'square' }
+      allow(subject).to receive(:raw_info) { { 'name' => 'User Without Pic' } }
       expect(subject.info[:image]).to be_nil
     end
 
-    describe "when a picture is returned from google" do
+    describe 'when a picture is returned from google' do
       it 'should return the image with size specified in the `image_size` option' do
-        @options = {:image_size => 50}
-        allow(subject).to receive(:raw_info) { {'picture' => 'https://lh3.googleusercontent.com/url/photo.jpg'} }
+        @options = { image_size: 50 }
+        allow(subject).to receive(:raw_info) { { 'picture' => 'https://lh3.googleusercontent.com/url/photo.jpg' } }
         expect(subject.info[:image]).to eq('https://lh3.googleusercontent.com/url/s50/photo.jpg')
       end
 
       it 'should handle a picture with too many slashes correctly' do
-        @options = {:image_size => 50}
-        allow(subject).to receive(:raw_info) { {'picture' => 'https://lh3.googleusercontent.com/url//photo.jpg'} }
+        @options = { image_size: 50 }
+        allow(subject).to receive(:raw_info) { { 'picture' => 'https://lh3.googleusercontent.com/url//photo.jpg' } }
         expect(subject.info[:image]).to eq('https://lh3.googleusercontent.com/url/s50/photo.jpg')
       end
 
       it 'should handle a picture with a size query parameter correctly' do
-        @options = {:image_size => 50}
-        allow(subject).to receive(:raw_info) { {'picture' => 'https://lh3.googleusercontent.com/url/photo.jpg?sz=50'} }
+        @options = { image_size: 50 }
+        allow(subject).to receive(:raw_info) { { 'picture' => 'https://lh3.googleusercontent.com/url/photo.jpg?sz=50' } }
         expect(subject.info[:image]).to eq('https://lh3.googleusercontent.com/url/s50/photo.jpg')
       end
 
       it 'should handle a picture with a size query parameter and other valid query parameters correctly' do
-        @options = {:image_size => 50}
-        allow(subject).to receive(:raw_info) { {'picture' => 'https://lh3.googleusercontent.com/url/photo.jpg?sz=50&hello=true&life=42'} }
+        @options = { image_size: 50 }
+        allow(subject).to receive(:raw_info) { { 'picture' => 'https://lh3.googleusercontent.com/url/photo.jpg?sz=50&hello=true&life=42' } }
         expect(subject.info[:image]).to eq('https://lh3.googleusercontent.com/url/s50/photo.jpg?hello=true&life=42')
       end
 
       it 'should handle a picture with other valid query parameters correctly' do
-        @options = {:image_size => 50}
-        allow(subject).to receive(:raw_info) { {'picture' => 'https://lh3.googleusercontent.com/url/photo.jpg?hello=true&life=42'} }
+        @options = { image_size: 50 }
+        allow(subject).to receive(:raw_info) { { 'picture' => 'https://lh3.googleusercontent.com/url/photo.jpg?hello=true&life=42' } }
         expect(subject.info[:image]).to eq('https://lh3.googleusercontent.com/url/s50/photo.jpg?hello=true&life=42')
       end
 
       it 'should return the image with width and height specified in the `image_size` option' do
-        @options = {:image_size => {:width => 50, :height => 40}}
-        allow(subject).to receive(:raw_info) { {'picture' => 'https://lh3.googleusercontent.com/url/photo.jpg'} }
+        @options = { image_size: { width: 50, height: 40 } }
+        allow(subject).to receive(:raw_info) { { 'picture' => 'https://lh3.googleusercontent.com/url/photo.jpg' } }
         expect(subject.info[:image]).to eq('https://lh3.googleusercontent.com/url/w50-h40/photo.jpg')
       end
 
       it 'should return square image when `image_aspect_ratio` is specified' do
-        @options = {:image_aspect_ratio => 'square'}
-        allow(subject).to receive(:raw_info) { {'picture' => 'https://lh3.googleusercontent.com/url/photo.jpg'} }
+        @options = { image_aspect_ratio: 'square' }
+        allow(subject).to receive(:raw_info) { { 'picture' => 'https://lh3.googleusercontent.com/url/photo.jpg' } }
         expect(subject.info[:image]).to eq('https://lh3.googleusercontent.com/url/c/photo.jpg')
       end
 
       it 'should return square sized image when `image_aspect_ratio` and `image_size` is set' do
-        @options = {:image_aspect_ratio => 'square', :image_size => 50}
-        allow(subject).to receive(:raw_info) { {'picture' => 'https://lh3.googleusercontent.com/url/photo.jpg'} }
+        @options = { image_aspect_ratio: 'square', image_size: 50 }
+        allow(subject).to receive(:raw_info) { { 'picture' => 'https://lh3.googleusercontent.com/url/photo.jpg' } }
         expect(subject.info[:image]).to eq('https://lh3.googleusercontent.com/url/s50-c/photo.jpg')
       end
 
       it 'should return square sized image when `image_aspect_ratio` and `image_size` has height and width' do
-        @options = {:image_aspect_ratio => 'square', :image_size => {:width => 50, :height => 40}}
-        allow(subject).to receive(:raw_info) { {'picture' => 'https://lh3.googleusercontent.com/url/photo.jpg'} }
+        @options = { image_aspect_ratio: 'square', image_size: { width: 50, height: 40 } }
+        allow(subject).to receive(:raw_info) { { 'picture' => 'https://lh3.googleusercontent.com/url/photo.jpg' } }
         expect(subject.info[:image]).to eq('https://lh3.googleusercontent.com/url/w50-h40-c/photo.jpg')
       end
 
       it 'should return original image if image url does not end in `photo.jpg`' do
-        @options = {:image_size => 50}
-        allow(subject).to receive(:raw_info) { {'picture' => 'https://lh3.googleusercontent.com/url/photograph.jpg'} }
+        @options = { image_size: 50 }
+        allow(subject).to receive(:raw_info) { { 'picture' => 'https://lh3.googleusercontent.com/url/photograph.jpg' } }
         expect(subject.info[:image]).to eq('https://lh3.googleusercontent.com/url/photograph.jpg')
       end
     end
 
     it 'should return original image if no options are provided' do
-      allow(subject).to receive(:raw_info) { {'picture' => 'https://lh3.googleusercontent.com/url/photo.jpg'} }
+      allow(subject).to receive(:raw_info) { { 'picture' => 'https://lh3.googleusercontent.com/url/photo.jpg' } }
       expect(subject.info[:image]).to eq('https://lh3.googleusercontent.com/url/photo.jpg')
     end
 
     it 'should return correct image if google image url has double https' do
-      allow(subject).to receive(:raw_info) { {'picture' => 'https:https://lh3.googleusercontent.com/url/photo.jpg'} }
+      allow(subject).to receive(:raw_info) { { 'picture' => 'https:https://lh3.googleusercontent.com/url/photo.jpg' } }
       expect(subject.info[:image]).to eq('https://lh3.googleusercontent.com/url/photo.jpg')
     end
   end
@@ -510,7 +532,7 @@
       auth_code = double(:auth_code)
       allow(client).to receive(:auth_code).and_return(auth_code)
       expect(subject).to receive(:client).and_return(client)
-      expect(auth_code).to receive(:get_token).with('valid_code', { :redirect_uri => 'postmessage'}, {})
+      expect(auth_code).to receive(:get_token).with('valid_code', { redirect_uri: 'postmessage' }, {})
 
       expect(subject).not_to receive(:orig_build_access_token)
       subject.build_access_token
@@ -524,7 +546,7 @@
       auth_code = double(:auth_code)
       allow(client).to receive(:auth_code).and_return(auth_code)
       expect(subject).to receive(:client).and_return(client)
-      expect(auth_code).to receive(:get_token).with('valid_code', { :redirect_uri => ''}, {})
+      expect(auth_code).to receive(:get_token).with('valid_code', { redirect_uri: '' }, {})
 
       expect(subject).not_to receive(:orig_build_access_token)
       subject.build_access_token
@@ -538,7 +560,7 @@
       auth_code = double(:auth_code)
       allow(client).to receive(:auth_code).and_return(auth_code)
       expect(subject).to receive(:client).and_return(client)
-      expect(auth_code).to receive(:get_token).with('valid_code', { :redirect_uri => 'redirect_uri'}, {})
+      expect(auth_code).to receive(:get_token).with('valid_code', { redirect_uri: 'redirect_uri' }, {})
 
       expect(subject).not_to receive(:orig_build_access_token)
       subject.build_access_token
@@ -566,7 +588,7 @@
       allow(subject).to receive(:callback_url).and_return('redirect_uri_without_query_string')
 
       expect(subject).to receive(:client).and_return(client)
-      expect(auth_code).to receive(:get_token).with('valid_code', { :redirect_uri => 'redirect_uri_without_query_string'}, {})
+      expect(auth_code).to receive(:get_token).with('valid_code', { redirect_uri: 'redirect_uri_without_query_string' }, {})
       subject.build_access_token
     end
   end
@@ -576,19 +598,19 @@
       subject.options.client_options[:connection_build] = proc do |builder|
         builder.request :url_encoded
         builder.adapter :test do |stub|
-          stub.get('/oauth2/v3/tokeninfo?access_token=valid_access_token') do |env|
-            [200, {'Content-Type' => 'application/json; charset=UTF-8'}, MultiJson.encode(
-              :aud => "000000000000.apps.googleusercontent.com",
-              :sub => "123456789",
-              :email_verified => "true",
-              :email => "example@example.com",
-              :access_type => "offline",
-              :scope => "profile email",
-              :expires_in => 436
+          stub.get('/oauth2/v3/tokeninfo?access_token=valid_access_token') do
+            [200, { 'Content-Type' => 'application/json; charset=UTF-8' }, MultiJson.encode(
+              aud: '000000000000.apps.googleusercontent.com',
+              sub: '123456789',
+              email_verified: 'true',
+              email: 'example@example.com',
+              access_type: 'offline',
+              scope: 'profile email',
+              expires_in: 436
             )]
           end
-          stub.get('/oauth2/v3/tokeninfo?access_token=invalid_access_token') do |env|
-            [400, {'Content-Type' => 'application/json; charset=UTF-8'}, MultiJson.encode(:error_description => 'Invalid Value')]
+          stub.get('/oauth2/v3/tokeninfo?access_token=invalid_access_token') do
+            [400, { 'Content-Type' => 'application/json; charset=UTF-8' }, MultiJson.encode(error_description: 'Invalid Value')]
           end
         end
       end
@@ -600,7 +622,7 @@
     end
 
     it 'should verify token if access_token is valid and app_id authorized' do
-      subject.options.authorized_client_ids = ["000000000000.apps.googleusercontent.com"]
+      subject.options.authorized_client_ids = ['000000000000.apps.googleusercontent.com']
       expect(subject.send(:verify_token, 'valid_access_token')).to eq(true)
     end
 
@@ -609,9 +631,9 @@
     end
 
     it 'should raise error if access_token is invalid' do
-      expect {
+      expect do
         subject.send(:verify_token, 'invalid_access_token')
-      }.to raise_error(OAuth2::Error)
+      end.to raise_error(OAuth2::Error)
     end
   end
 
@@ -620,9 +642,9 @@
       OAuth2::Client.new('abc', 'def') do |builder|
         builder.request :url_encoded
         builder.adapter :test do |stub|
-          stub.get('/plus/v1/people/me/openIdConnect') do |env|
-            [200, {'Content-Type' => 'application/json; charset=UTF-8'}, MultiJson.encode(
-              :hd => 'example.com',
+          stub.get('/plus/v1/people/me/openIdConnect') do
+            [200, { 'Content-Type' => 'application/json; charset=UTF-8' }, MultiJson.encode(
+              hd: 'example.com'
             )]
           end
         end
@@ -635,8 +657,8 @@
         OAuth2::Client.new('abc', 'def') do |builder|
           builder.request :url_encoded
           builder.adapter :test do |stub|
-            stub.get('/plus/v1/people/me/openIdConnect') do |env|
-              [200, {'Content-Type' => 'application/json; charset=UTF-8'}, MultiJson.encode({})]
+            stub.get('/plus/v1/people/me/openIdConnect') do
+              [200, { 'Content-Type' => 'application/json; charset=UTF-8' }, MultiJson.encode({})]
             end
           end
         end
@@ -654,9 +676,9 @@
 
       it 'should raise an exception if nil is not included' do
         subject.options.hd = ['example.com', 'example.co']
-        expect {
+        expect do
           subject.send(:verify_hd, access_token)
-        }.to raise_error(OmniAuth::Strategies::OAuth2::CallbackError)
+        end.to raise_error(OmniAuth::Strategies::OAuth2::CallbackError)
       end
     end
 
@@ -673,29 +695,29 @@
       subject.options.hd = ['example.com', 'example.co', nil]
       expect(subject.send(:verify_hd, access_token)).to eq(true)
     end
-    
+
     it 'should verify hd if options hd is set as an Proc and is correct' do
-      subject.options.hd = Proc.new { 'example.com' }
+      subject.options.hd = proc { 'example.com' }
       expect(subject.send(:verify_hd, access_token)).to eq(true)
     end
-    
+
     it 'should verify hd if options hd is set as an Proc returning an array and is correct' do
-      subject.options.hd = Proc.new { ['example.com', 'example.co'] }
+      subject.options.hd = proc { ['example.com', 'example.co'] }
       expect(subject.send(:verify_hd, access_token)).to eq(true)
     end
 
     it 'should raise error if options hd is set and wrong' do
       subject.options.hd = 'invalid.com'
-      expect {
+      expect do
         subject.send(:verify_hd, access_token)
-      }.to raise_error(OmniAuth::Strategies::GoogleOauth2::CallbackError)
+      end.to raise_error(OmniAuth::Strategies::GoogleOauth2::CallbackError)
     end
 
     it 'should raise error if options hd is set as an array and is not correct' do
       subject.options.hd = ['invalid.com', 'invalid.co']
-      expect {
+      expect do
         subject.send(:verify_hd, access_token)
-      }.to raise_error(OmniAuth::Strategies::GoogleOauth2::CallbackError)
+      end.to raise_error(OmniAuth::Strategies::GoogleOauth2::CallbackError)
     end
   end
 end
diff --git a/spec/rubocop_spec.rb b/spec/rubocop_spec.rb
new file mode 100644
index 0000000..eca9b45
--- /dev/null
+++ b/spec/rubocop_spec.rb
@@ -0,0 +1,9 @@
+# frozen_string_literal: true
+
+require_relative 'spec_helper'
+
+describe 'Rubocop' do
+  it 'should pass with no offenses detected' do
+    expect(`rubocop`).to include('no offenses detected')
+  end
+end
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
index 9d08904..3c23253 100644
--- a/spec/spec_helper.rb
+++ b/spec/spec_helper.rb
@@ -1,2 +1,4 @@
+# frozen_string_literal: true
+
 require File.join('bundler', 'setup')
-require 'rspec'
\ No newline at end of file
+require 'rspec'