diff --git a/Gemfile b/Gemfile
index 57494b93..f5689e34 100644
--- a/Gemfile
+++ b/Gemfile
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 source "https://rubygems.org"
 
 gemspec
diff --git a/Rakefile b/Rakefile
index bbf71663..6e2ab180 100644
--- a/Rakefile
+++ b/Rakefile
@@ -1,4 +1,5 @@
 # encoding: UTF-8
+# frozen_string_literal: true
 
 require 'bundler/gem_tasks'
 require 'rake/testtask'
diff --git a/app/controllers/devise/confirmations_controller.rb b/app/controllers/devise/confirmations_controller.rb
index 4981545a..3069c6ef 100644
--- a/app/controllers/devise/confirmations_controller.rb
+++ b/app/controllers/devise/confirmations_controller.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 class Devise::ConfirmationsController < DeviseController
   # GET /resource/confirmation/new
   def new
diff --git a/app/controllers/devise/omniauth_callbacks_controller.rb b/app/controllers/devise/omniauth_callbacks_controller.rb
index d5b2c094..5f3f89d7 100644
--- a/app/controllers/devise/omniauth_callbacks_controller.rb
+++ b/app/controllers/devise/omniauth_callbacks_controller.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 class Devise::OmniauthCallbacksController < DeviseController
   prepend_before_action { request.env["devise.skip_timeout"] = true }
 
diff --git a/app/controllers/devise/passwords_controller.rb b/app/controllers/devise/passwords_controller.rb
index f4291c76..010199a7 100644
--- a/app/controllers/devise/passwords_controller.rb
+++ b/app/controllers/devise/passwords_controller.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 class Devise::PasswordsController < DeviseController
   prepend_before_action :require_no_authentication
   # Render the #edit only if coming from a reset password email link
diff --git a/app/controllers/devise/registrations_controller.rb b/app/controllers/devise/registrations_controller.rb
index 31ba0887..ca2bb34c 100644
--- a/app/controllers/devise/registrations_controller.rb
+++ b/app/controllers/devise/registrations_controller.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 class Devise::RegistrationsController < DeviseController
   prepend_before_action :require_no_authentication, only: [:new, :create, :cancel]
   prepend_before_action :authenticate_scope!, only: [:edit, :update, :destroy]
diff --git a/app/controllers/devise/sessions_controller.rb b/app/controllers/devise/sessions_controller.rb
index d04c3aa8..9090b002 100644
--- a/app/controllers/devise/sessions_controller.rb
+++ b/app/controllers/devise/sessions_controller.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 class Devise::SessionsController < DeviseController
   prepend_before_action :require_no_authentication, only: [:new, :create]
   prepend_before_action :allow_params_authentication!, only: :create
diff --git a/app/controllers/devise/unlocks_controller.rb b/app/controllers/devise/unlocks_controller.rb
index 179c9525..1d04d622 100644
--- a/app/controllers/devise/unlocks_controller.rb
+++ b/app/controllers/devise/unlocks_controller.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 class Devise::UnlocksController < DeviseController
   prepend_before_action :require_no_authentication
 
diff --git a/app/controllers/devise_controller.rb b/app/controllers/devise_controller.rb
index 0679a62e..702b97bd 100644
--- a/app/controllers/devise_controller.rb
+++ b/app/controllers/devise_controller.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 # All Devise controllers are inherited from here.
 class DeviseController < Devise.parent_controller.constantize
   include Devise::Controllers::ScopedViews
diff --git a/app/helpers/devise_helper.rb b/app/helpers/devise_helper.rb
index f2d07261..c29120f7 100644
--- a/app/helpers/devise_helper.rb
+++ b/app/helpers/devise_helper.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module DeviseHelper
   # A simple way to show error messages for the current devise resource. If you need
   # to customize this method, you can either overwrite it in your application helpers or
diff --git a/app/mailers/devise/mailer.rb b/app/mailers/devise/mailer.rb
index 857a8bc6..11ef449c 100644
--- a/app/mailers/devise/mailer.rb
+++ b/app/mailers/devise/mailer.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 if defined?(ActionMailer)
   class Devise::Mailer < Devise.parent_mailer.constantize
     include Devise::Mailers::Helpers
diff --git a/devise.gemspec b/devise.gemspec
index 3e67230b..18a43002 100644
--- a/devise.gemspec
+++ b/devise.gemspec
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 # -*- encoding: utf-8 -*-
 $:.push File.expand_path("../lib", __FILE__)
 require "devise/version"
diff --git a/gemfiles/Gemfile.rails-4.1-stable b/gemfiles/Gemfile.rails-4.1-stable
index 2dde99dd..28416032 100644
--- a/gemfiles/Gemfile.rails-4.1-stable
+++ b/gemfiles/Gemfile.rails-4.1-stable
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 source "https://rubygems.org"
 
 gemspec path: ".."
diff --git a/gemfiles/Gemfile.rails-4.2-stable b/gemfiles/Gemfile.rails-4.2-stable
index 8165a950..7856859f 100644
--- a/gemfiles/Gemfile.rails-4.2-stable
+++ b/gemfiles/Gemfile.rails-4.2-stable
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 source "https://rubygems.org"
 
 gemspec path: ".."
diff --git a/gemfiles/Gemfile.rails-5.0-stable b/gemfiles/Gemfile.rails-5.0-stable
index af0e3b47..6ae87244 100644
--- a/gemfiles/Gemfile.rails-5.0-stable
+++ b/gemfiles/Gemfile.rails-5.0-stable
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 source "https://rubygems.org"
 
 gemspec path: ".."
diff --git a/guides/bug_report_templates/integration_test.rb b/guides/bug_report_templates/integration_test.rb
index 6fea86bb..b3eecd22 100644
--- a/guides/bug_report_templates/integration_test.rb
+++ b/guides/bug_report_templates/integration_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 begin
   require 'bundler/inline'
 rescue LoadError => e
diff --git a/lib/devise.rb b/lib/devise.rb
index 3627f2da..16049382 100755
--- a/lib/devise.rb
+++ b/lib/devise.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'rails'
 require 'active_support/core_ext/numeric/time'
 require 'active_support/dependencies'
diff --git a/lib/devise/controllers/helpers.rb b/lib/devise/controllers/helpers.rb
index 81d5e385..7e67660a 100644
--- a/lib/devise/controllers/helpers.rb
+++ b/lib/devise/controllers/helpers.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Devise
   module Controllers
     # Those helpers are convenience methods added to ApplicationController.
diff --git a/lib/devise/controllers/rememberable.rb b/lib/devise/controllers/rememberable.rb
index 02bdaf11..420a2f78 100644
--- a/lib/devise/controllers/rememberable.rb
+++ b/lib/devise/controllers/rememberable.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Devise
   module Controllers
     # A module that may be optionally included in a controller in order
diff --git a/lib/devise/controllers/scoped_views.rb b/lib/devise/controllers/scoped_views.rb
index 7ba965e5..989d3879 100644
--- a/lib/devise/controllers/scoped_views.rb
+++ b/lib/devise/controllers/scoped_views.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Devise
   module Controllers
     module ScopedViews
diff --git a/lib/devise/controllers/sign_in_out.rb b/lib/devise/controllers/sign_in_out.rb
index 77c5987b..2d38ab23 100644
--- a/lib/devise/controllers/sign_in_out.rb
+++ b/lib/devise/controllers/sign_in_out.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Devise
   module Controllers
     # Provide sign in and sign out functionality.
diff --git a/lib/devise/controllers/store_location.rb b/lib/devise/controllers/store_location.rb
index 91655a35..fa8cb342 100644
--- a/lib/devise/controllers/store_location.rb
+++ b/lib/devise/controllers/store_location.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "uri"
 
 module Devise
diff --git a/lib/devise/controllers/url_helpers.rb b/lib/devise/controllers/url_helpers.rb
index fed1383f..3da36423 100644
--- a/lib/devise/controllers/url_helpers.rb
+++ b/lib/devise/controllers/url_helpers.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Devise
   module Controllers
     # Create url helpers to be used with resource/scope configuration. Acts as
diff --git a/lib/devise/delegator.rb b/lib/devise/delegator.rb
index 361d4cff..d04f15f1 100644
--- a/lib/devise/delegator.rb
+++ b/lib/devise/delegator.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Devise
   # Checks the scope in the given environment and returns the associated failure app.
   class Delegator
diff --git a/lib/devise/encryptor.rb b/lib/devise/encryptor.rb
index 19651d7b..7a53bef3 100644
--- a/lib/devise/encryptor.rb
+++ b/lib/devise/encryptor.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'bcrypt'
 
 module Devise
diff --git a/lib/devise/failure_app.rb b/lib/devise/failure_app.rb
index 4f7a3ddc..047c5c3f 100644
--- a/lib/devise/failure_app.rb
+++ b/lib/devise/failure_app.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "action_controller/metal"
 
 module Devise
diff --git a/lib/devise/hooks/activatable.rb b/lib/devise/hooks/activatable.rb
index 805c2c57..b2eaea19 100644
--- a/lib/devise/hooks/activatable.rb
+++ b/lib/devise/hooks/activatable.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 # Deny user access whenever their account is not active yet.
 # We need this as hook to validate the user activity on each request
 # and in case the user is using other strategies beside Devise ones.
diff --git a/lib/devise/hooks/csrf_cleaner.rb b/lib/devise/hooks/csrf_cleaner.rb
index 28d4aea8..d725fbc4 100644
--- a/lib/devise/hooks/csrf_cleaner.rb
+++ b/lib/devise/hooks/csrf_cleaner.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 Warden::Manager.after_authentication do |record, warden, options|
   clean_up_for_winning_strategy = !warden.winning_strategy.respond_to?(:clean_up_csrf?) ||
     warden.winning_strategy.clean_up_csrf?
diff --git a/lib/devise/hooks/forgetable.rb b/lib/devise/hooks/forgetable.rb
index 50e2062c..317dc547 100644
--- a/lib/devise/hooks/forgetable.rb
+++ b/lib/devise/hooks/forgetable.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 # Before logout hook to forget the user in the given scope, if it responds
 # to forget_me! Also clear remember token to ensure the user won't be
 # remembered again. Notice that we forget the user unless the record is not persisted.
diff --git a/lib/devise/hooks/lockable.rb b/lib/devise/hooks/lockable.rb
index c9d4df14..a73a1752 100644
--- a/lib/devise/hooks/lockable.rb
+++ b/lib/devise/hooks/lockable.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 # After each sign in, if resource responds to failed_attempts, sets it to 0
 # This is only triggered when the user is explicitly set (with set_user)
 Warden::Manager.after_set_user except: :fetch do |record, warden, options|
diff --git a/lib/devise/hooks/proxy.rb b/lib/devise/hooks/proxy.rb
index 24de988e..96b3a07e 100644
--- a/lib/devise/hooks/proxy.rb
+++ b/lib/devise/hooks/proxy.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Devise
   module Hooks
     # A small warden proxy so we can remember, forget and
diff --git a/lib/devise/hooks/rememberable.rb b/lib/devise/hooks/rememberable.rb
index 077be534..345f2f24 100644
--- a/lib/devise/hooks/rememberable.rb
+++ b/lib/devise/hooks/rememberable.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 Warden::Manager.after_set_user except: :fetch do |record, warden, options|
   scope = options[:scope]
   if record.respond_to?(:remember_me) && options[:store] != false &&
diff --git a/lib/devise/hooks/timeoutable.rb b/lib/devise/hooks/timeoutable.rb
index 1bfa07d7..41b1fde8 100644
--- a/lib/devise/hooks/timeoutable.rb
+++ b/lib/devise/hooks/timeoutable.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 # Each time a record is set we check whether its session has already timed out
 # or not, based on last request time. If so, the record is logged out and
 # redirected to the sign in page. Also, each time the request comes and the
diff --git a/lib/devise/hooks/trackable.rb b/lib/devise/hooks/trackable.rb
index 9bb21288..53ac30dd 100644
--- a/lib/devise/hooks/trackable.rb
+++ b/lib/devise/hooks/trackable.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 # After each sign in, update sign in time, sign in count and sign in IP.
 # This is only triggered when the user is explicitly set (with set_user)
 # and on authentication. Retrieving the user from session (:fetch) does
diff --git a/lib/devise/mailers/helpers.rb b/lib/devise/mailers/helpers.rb
index 12cac733..f6997462 100644
--- a/lib/devise/mailers/helpers.rb
+++ b/lib/devise/mailers/helpers.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Devise
   module Mailers
     module Helpers
diff --git a/lib/devise/mapping.rb b/lib/devise/mapping.rb
index af4a1412..7692020f 100644
--- a/lib/devise/mapping.rb
+++ b/lib/devise/mapping.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Devise
   # Responsible for handling devise mappings and routes configuration. Each
   # resource configured by devise_for in routes is actually creating a mapping
diff --git a/lib/devise/models.rb b/lib/devise/models.rb
index 6419814d..4d50fa24 100644
--- a/lib/devise/models.rb
+++ b/lib/devise/models.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Devise
   module Models
     class MissingAttribute < StandardError
diff --git a/lib/devise/models/authenticatable.rb b/lib/devise/models/authenticatable.rb
index 1246d90d..0ed15041 100644
--- a/lib/devise/models/authenticatable.rb
+++ b/lib/devise/models/authenticatable.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'active_model/version'
 require 'devise/hooks/activatable'
 require 'devise/hooks/csrf_cleaner'
diff --git a/lib/devise/models/confirmable.rb b/lib/devise/models/confirmable.rb
index 726b8fa9..5dfcd772 100644
--- a/lib/devise/models/confirmable.rb
+++ b/lib/devise/models/confirmable.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Devise
   module Models
     # Confirmable is responsible to verify if an account is already confirmed to
diff --git a/lib/devise/models/database_authenticatable.rb b/lib/devise/models/database_authenticatable.rb
index 69967239..a91b21ca 100644
--- a/lib/devise/models/database_authenticatable.rb
+++ b/lib/devise/models/database_authenticatable.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'devise/strategies/database_authenticatable'
 
 module Devise
diff --git a/lib/devise/models/lockable.rb b/lib/devise/models/lockable.rb
index fe05b255..b97d12d3 100644
--- a/lib/devise/models/lockable.rb
+++ b/lib/devise/models/lockable.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "devise/hooks/lockable"
 
 module Devise
diff --git a/lib/devise/models/omniauthable.rb b/lib/devise/models/omniauthable.rb
index c1faf37a..c0fe1e54 100644
--- a/lib/devise/models/omniauthable.rb
+++ b/lib/devise/models/omniauthable.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'devise/omniauth'
 
 module Devise
diff --git a/lib/devise/models/recoverable.rb b/lib/devise/models/recoverable.rb
index 7857b686..75318d50 100644
--- a/lib/devise/models/recoverable.rb
+++ b/lib/devise/models/recoverable.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Devise
   module Models
 
diff --git a/lib/devise/models/registerable.rb b/lib/devise/models/registerable.rb
index 1f10dd2e..3965ee5c 100644
--- a/lib/devise/models/registerable.rb
+++ b/lib/devise/models/registerable.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Devise
   module Models
     # Registerable is responsible for everything related to registering a new
diff --git a/lib/devise/models/rememberable.rb b/lib/devise/models/rememberable.rb
index 5b72ebba..5a175013 100644
--- a/lib/devise/models/rememberable.rb
+++ b/lib/devise/models/rememberable.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'devise/strategies/rememberable'
 require 'devise/hooks/rememberable'
 require 'devise/hooks/forgetable'
diff --git a/lib/devise/models/timeoutable.rb b/lib/devise/models/timeoutable.rb
index d589e24a..ee187dbf 100644
--- a/lib/devise/models/timeoutable.rb
+++ b/lib/devise/models/timeoutable.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'devise/hooks/timeoutable'
 
 module Devise
diff --git a/lib/devise/models/trackable.rb b/lib/devise/models/trackable.rb
index adee0eaa..9a3056e9 100644
--- a/lib/devise/models/trackable.rb
+++ b/lib/devise/models/trackable.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'devise/hooks/trackable'
 
 module Devise
diff --git a/lib/devise/models/validatable.rb b/lib/devise/models/validatable.rb
index 1ad2e70e..91890fb5 100644
--- a/lib/devise/models/validatable.rb
+++ b/lib/devise/models/validatable.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Devise
   module Models
     # Validatable creates all needed validations for a user email and password.
diff --git a/lib/devise/modules.rb b/lib/devise/modules.rb
index 2af8820b..d8cde834 100644
--- a/lib/devise/modules.rb
+++ b/lib/devise/modules.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'active_support/core_ext/object/with_options'
 
 Devise.with_options model: true do |d|
diff --git a/lib/devise/omniauth.rb b/lib/devise/omniauth.rb
index ff342fd7..63ea6ca5 100644
--- a/lib/devise/omniauth.rb
+++ b/lib/devise/omniauth.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 begin
   require "omniauth"
   require "omniauth/version"
diff --git a/lib/devise/omniauth/config.rb b/lib/devise/omniauth/config.rb
index e22d701c..2d3749ff 100644
--- a/lib/devise/omniauth/config.rb
+++ b/lib/devise/omniauth/config.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Devise
   module OmniAuth
     class StrategyNotFound < NameError
diff --git a/lib/devise/omniauth/url_helpers.rb b/lib/devise/omniauth/url_helpers.rb
index f2cc3dbc..72eac65e 100644
--- a/lib/devise/omniauth/url_helpers.rb
+++ b/lib/devise/omniauth/url_helpers.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Devise
   module OmniAuth
     module UrlHelpers
diff --git a/lib/devise/orm/active_record.rb b/lib/devise/orm/active_record.rb
index de114825..0fecf64e 100644
--- a/lib/devise/orm/active_record.rb
+++ b/lib/devise/orm/active_record.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'orm_adapter/adapters/active_record'
 
 ActiveSupport.on_load(:active_record) do
diff --git a/lib/devise/orm/mongoid.rb b/lib/devise/orm/mongoid.rb
index cc2f1c55..034501ef 100644
--- a/lib/devise/orm/mongoid.rb
+++ b/lib/devise/orm/mongoid.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 ActiveSupport.on_load(:mongoid) do
   require 'orm_adapter/adapters/mongoid'
 
diff --git a/lib/devise/parameter_filter.rb b/lib/devise/parameter_filter.rb
index 63d06f90..d61e66d1 100644
--- a/lib/devise/parameter_filter.rb
+++ b/lib/devise/parameter_filter.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Devise
   class ParameterFilter
     def initialize(case_insensitive_keys, strip_whitespace_keys)
diff --git a/lib/devise/parameter_sanitizer.rb b/lib/devise/parameter_sanitizer.rb
index 0f6faee6..91060c66 100644
--- a/lib/devise/parameter_sanitizer.rb
+++ b/lib/devise/parameter_sanitizer.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Devise
   # The +ParameterSanitizer+ deals with permitting specific parameters values
   # for each +Devise+ scope in the application.
diff --git a/lib/devise/rails.rb b/lib/devise/rails.rb
index 6321c71d..d23aade5 100644
--- a/lib/devise/rails.rb
+++ b/lib/devise/rails.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'devise/rails/routes'
 require 'devise/rails/warden_compat'
 
diff --git a/lib/devise/rails/routes.rb b/lib/devise/rails/routes.rb
index 9a02363e..2d177b25 100644
--- a/lib/devise/rails/routes.rb
+++ b/lib/devise/rails/routes.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "active_support/core_ext/object/try"
 require "active_support/core_ext/hash/slice"
 
diff --git a/lib/devise/rails/warden_compat.rb b/lib/devise/rails/warden_compat.rb
index 553e8e44..3db7ecae 100644
--- a/lib/devise/rails/warden_compat.rb
+++ b/lib/devise/rails/warden_compat.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Warden::Mixins::Common
   def request
     @request ||= ActionDispatch::Request.new(env)
diff --git a/lib/devise/strategies/authenticatable.rb b/lib/devise/strategies/authenticatable.rb
index 13249e82..afcbef0b 100644
--- a/lib/devise/strategies/authenticatable.rb
+++ b/lib/devise/strategies/authenticatable.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'devise/strategies/base'
 
 module Devise
diff --git a/lib/devise/strategies/base.rb b/lib/devise/strategies/base.rb
index ee5c8c7f..998e6a36 100644
--- a/lib/devise/strategies/base.rb
+++ b/lib/devise/strategies/base.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Devise
   module Strategies
     # Base strategy for Devise. Responsible for verifying correct scope and mapping.
diff --git a/lib/devise/strategies/database_authenticatable.rb b/lib/devise/strategies/database_authenticatable.rb
index 3d8f4072..fe9812ab 100644
--- a/lib/devise/strategies/database_authenticatable.rb
+++ b/lib/devise/strategies/database_authenticatable.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'devise/strategies/authenticatable'
 
 module Devise
diff --git a/lib/devise/strategies/rememberable.rb b/lib/devise/strategies/rememberable.rb
index 3a09a6b4..fe20804f 100644
--- a/lib/devise/strategies/rememberable.rb
+++ b/lib/devise/strategies/rememberable.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'devise/strategies/authenticatable'
 
 module Devise
diff --git a/lib/devise/test/controller_helpers.rb b/lib/devise/test/controller_helpers.rb
index 89060e57..a5447f09 100644
--- a/lib/devise/test/controller_helpers.rb
+++ b/lib/devise/test/controller_helpers.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Devise
   module Test
     # `Devise::Test::ControllerHelpers` provides a facility to test controllers
diff --git a/lib/devise/test/integration_helpers.rb b/lib/devise/test/integration_helpers.rb
index e39b6792..99731389 100644
--- a/lib/devise/test/integration_helpers.rb
+++ b/lib/devise/test/integration_helpers.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Devise
   # Devise::Test::IntegrationHelpers is a helper module for facilitating
   # authentication on Rails integration tests to bypass the required steps for
diff --git a/lib/devise/test_helpers.rb b/lib/devise/test_helpers.rb
index fbaed4cd..c5b52fad 100644
--- a/lib/devise/test_helpers.rb
+++ b/lib/devise/test_helpers.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Devise
   module TestHelpers
     def self.included(base)
diff --git a/lib/devise/time_inflector.rb b/lib/devise/time_inflector.rb
index 94795afd..db3f6558 100644
--- a/lib/devise/time_inflector.rb
+++ b/lib/devise/time_inflector.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "active_support/core_ext/module/delegation"
 
 module Devise
diff --git a/lib/devise/token_generator.rb b/lib/devise/token_generator.rb
index 636a1e78..9eb74a04 100644
--- a/lib/devise/token_generator.rb
+++ b/lib/devise/token_generator.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'openssl'
 
 module Devise
diff --git a/lib/devise/version.rb b/lib/devise/version.rb
index ac983193..44b6adf2 100644
--- a/lib/devise/version.rb
+++ b/lib/devise/version.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Devise
   VERSION = "4.3.0".freeze
 end
diff --git a/lib/generators/active_record/devise_generator.rb b/lib/generators/active_record/devise_generator.rb
index ffcca870..b5640bf8 100644
--- a/lib/generators/active_record/devise_generator.rb
+++ b/lib/generators/active_record/devise_generator.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'rails/generators/active_record'
 require 'generators/devise/orm_helpers'
 
diff --git a/lib/generators/active_record/templates/migration.rb b/lib/generators/active_record/templates/migration.rb
index 2df528a9..deed9859 100644
--- a/lib/generators/active_record/templates/migration.rb
+++ b/lib/generators/active_record/templates/migration.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 class DeviseCreate<%= table_name.camelize %> < ActiveRecord::Migration<%= migration_version %>
   def change
     create_table :<%= table_name %> do |t|
diff --git a/lib/generators/active_record/templates/migration_existing.rb b/lib/generators/active_record/templates/migration_existing.rb
index d7893343..a44e5413 100644
--- a/lib/generators/active_record/templates/migration_existing.rb
+++ b/lib/generators/active_record/templates/migration_existing.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 class AddDeviseTo<%= table_name.camelize %> < ActiveRecord::Migration<%= migration_version %>
   def self.up
     change_table :<%= table_name %> do |t|
diff --git a/lib/generators/devise/controllers_generator.rb b/lib/generators/devise/controllers_generator.rb
index 803ba041..c91371a3 100644
--- a/lib/generators/devise/controllers_generator.rb
+++ b/lib/generators/devise/controllers_generator.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'rails/generators/base'
 
 module Devise
diff --git a/lib/generators/devise/devise_generator.rb b/lib/generators/devise/devise_generator.rb
index ea7054c7..79f860ba 100644
--- a/lib/generators/devise/devise_generator.rb
+++ b/lib/generators/devise/devise_generator.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'rails/generators/named_base'
 
 module Devise
diff --git a/lib/generators/devise/install_generator.rb b/lib/generators/devise/install_generator.rb
index 6c6626b1..f81494d6 100644
--- a/lib/generators/devise/install_generator.rb
+++ b/lib/generators/devise/install_generator.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'rails/generators/base'
 require 'securerandom'
 
diff --git a/lib/generators/devise/orm_helpers.rb b/lib/generators/devise/orm_helpers.rb
index f67204b3..34afc38d 100644
--- a/lib/generators/devise/orm_helpers.rb
+++ b/lib/generators/devise/orm_helpers.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Devise
   module Generators
     module OrmHelpers
diff --git a/lib/generators/devise/views_generator.rb b/lib/generators/devise/views_generator.rb
index 2faacd5a..29bf8fed 100644
--- a/lib/generators/devise/views_generator.rb
+++ b/lib/generators/devise/views_generator.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'rails/generators/base'
 
 module Devise
diff --git a/lib/generators/mongoid/devise_generator.rb b/lib/generators/mongoid/devise_generator.rb
index 4ff57f06..40a8ac27 100644
--- a/lib/generators/mongoid/devise_generator.rb
+++ b/lib/generators/mongoid/devise_generator.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'rails/generators/named_base'
 require 'generators/devise/orm_helpers'
 
diff --git a/lib/generators/templates/controllers/confirmations_controller.rb b/lib/generators/templates/controllers/confirmations_controller.rb
index 480ee9a0..e0466111 100644
--- a/lib/generators/templates/controllers/confirmations_controller.rb
+++ b/lib/generators/templates/controllers/confirmations_controller.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 class <%= @scope_prefix %>ConfirmationsController < Devise::ConfirmationsController
   # GET /resource/confirmation/new
   # def new
diff --git a/lib/generators/templates/controllers/omniauth_callbacks_controller.rb b/lib/generators/templates/controllers/omniauth_callbacks_controller.rb
index cc122dc4..5f95be2d 100644
--- a/lib/generators/templates/controllers/omniauth_callbacks_controller.rb
+++ b/lib/generators/templates/controllers/omniauth_callbacks_controller.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 class <%= @scope_prefix %>OmniauthCallbacksController < Devise::OmniauthCallbacksController
   # You should configure your model like this:
   # devise :omniauthable, omniauth_providers: [:twitter]
diff --git a/lib/generators/templates/controllers/passwords_controller.rb b/lib/generators/templates/controllers/passwords_controller.rb
index 3409d435..afd468cc 100644
--- a/lib/generators/templates/controllers/passwords_controller.rb
+++ b/lib/generators/templates/controllers/passwords_controller.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 class <%= @scope_prefix %>PasswordsController < Devise::PasswordsController
   # GET /resource/password/new
   # def new
diff --git a/lib/generators/templates/controllers/registrations_controller.rb b/lib/generators/templates/controllers/registrations_controller.rb
index 3ffd29e9..cdd91acc 100644
--- a/lib/generators/templates/controllers/registrations_controller.rb
+++ b/lib/generators/templates/controllers/registrations_controller.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 class <%= @scope_prefix %>RegistrationsController < Devise::RegistrationsController
   # before_action :configure_sign_up_params, only: [:create]
   # before_action :configure_account_update_params, only: [:update]
diff --git a/lib/generators/templates/controllers/sessions_controller.rb b/lib/generators/templates/controllers/sessions_controller.rb
index 69afe4b4..f229c9b4 100644
--- a/lib/generators/templates/controllers/sessions_controller.rb
+++ b/lib/generators/templates/controllers/sessions_controller.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 class <%= @scope_prefix %>SessionsController < Devise::SessionsController
   # before_action :configure_sign_in_params, only: [:create]
 
diff --git a/lib/generators/templates/controllers/unlocks_controller.rb b/lib/generators/templates/controllers/unlocks_controller.rb
index 0e2cced5..0eadbbf6 100644
--- a/lib/generators/templates/controllers/unlocks_controller.rb
+++ b/lib/generators/templates/controllers/unlocks_controller.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 class <%= @scope_prefix %>UnlocksController < Devise::UnlocksController
   # GET /resource/unlock/new
   # def new
diff --git a/lib/generators/templates/devise.rb b/lib/generators/templates/devise.rb
index e3d9ede7..17bd5073 100755
--- a/lib/generators/templates/devise.rb
+++ b/lib/generators/templates/devise.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 # Use this hook to configure devise mailer, warden hooks and so forth.
 # Many of these configuration options can be set straight in your model.
 Devise.setup do |config|
diff --git a/test/controllers/custom_registrations_controller_test.rb b/test/controllers/custom_registrations_controller_test.rb
index 13e4eef2..683322eb 100644
--- a/test/controllers/custom_registrations_controller_test.rb
+++ b/test/controllers/custom_registrations_controller_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'test_helper'
 
 class CustomRegistrationsControllerTest < Devise::ControllerTestCase
diff --git a/test/controllers/custom_strategy_test.rb b/test/controllers/custom_strategy_test.rb
index b63bead6..c39ac3e6 100644
--- a/test/controllers/custom_strategy_test.rb
+++ b/test/controllers/custom_strategy_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'test_helper'
 require 'ostruct'
 require 'warden/strategies/base'
diff --git a/test/controllers/helper_methods_test.rb b/test/controllers/helper_methods_test.rb
index 59f913fd..5e20477c 100644
--- a/test/controllers/helper_methods_test.rb
+++ b/test/controllers/helper_methods_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'test_helper'
 
 class ApiController < ActionController::Metal
diff --git a/test/controllers/helpers_test.rb b/test/controllers/helpers_test.rb
index acbfe404..2380d362 100644
--- a/test/controllers/helpers_test.rb
+++ b/test/controllers/helpers_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'test_helper'
 require 'ostruct'
 
diff --git a/test/controllers/inherited_controller_i18n_messages_test.rb b/test/controllers/inherited_controller_i18n_messages_test.rb
index 677ce30f..f5d142d2 100644
--- a/test/controllers/inherited_controller_i18n_messages_test.rb
+++ b/test/controllers/inherited_controller_i18n_messages_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'test_helper'
 
 class SessionsInheritedController < Devise::SessionsController
diff --git a/test/controllers/internal_helpers_test.rb b/test/controllers/internal_helpers_test.rb
index d2a96119..7710e0d7 100644
--- a/test/controllers/internal_helpers_test.rb
+++ b/test/controllers/internal_helpers_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'test_helper'
 
 class MyController < DeviseController
diff --git a/test/controllers/load_hooks_controller_test.rb b/test/controllers/load_hooks_controller_test.rb
index cf8f4544..6387b309 100644
--- a/test/controllers/load_hooks_controller_test.rb
+++ b/test/controllers/load_hooks_controller_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'test_helper'
 
 class LoadHooksControllerTest < Devise::ControllerTestCase
diff --git a/test/controllers/passwords_controller_test.rb b/test/controllers/passwords_controller_test.rb
index 5c359eed..887e0133 100644
--- a/test/controllers/passwords_controller_test.rb
+++ b/test/controllers/passwords_controller_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'test_helper'
 
 class PasswordsControllerTest < Devise::ControllerTestCase
diff --git a/test/controllers/sessions_controller_test.rb b/test/controllers/sessions_controller_test.rb
index 69b65f37..e88cf7e9 100644
--- a/test/controllers/sessions_controller_test.rb
+++ b/test/controllers/sessions_controller_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'test_helper'
 
 class SessionsControllerTest < Devise::ControllerTestCase
diff --git a/test/controllers/url_helpers_test.rb b/test/controllers/url_helpers_test.rb
index a4db0901..d5328a36 100644
--- a/test/controllers/url_helpers_test.rb
+++ b/test/controllers/url_helpers_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'test_helper'
 
 class RoutesTest < Devise::ControllerTestCase
diff --git a/test/delegator_test.rb b/test/delegator_test.rb
index 65dda06e..851afbca 100644
--- a/test/delegator_test.rb
+++ b/test/delegator_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'test_helper'
 
 class DelegatorTest < ActiveSupport::TestCase
diff --git a/test/devise_test.rb b/test/devise_test.rb
index 07377cc6..088527fe 100755
--- a/test/devise_test.rb
+++ b/test/devise_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'test_helper'
 
 module Devise
diff --git a/test/failure_app_test.rb b/test/failure_app_test.rb
index ee6d19fb..b37a9f00 100644
--- a/test/failure_app_test.rb
+++ b/test/failure_app_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'test_helper'
 require 'ostruct'
 
diff --git a/test/generators/active_record_generator_test.rb b/test/generators/active_record_generator_test.rb
index 79fab2b1..006ec5d3 100644
--- a/test/generators/active_record_generator_test.rb
+++ b/test/generators/active_record_generator_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "test_helper"
 
 if DEVISE_ORM == :active_record
diff --git a/test/generators/controllers_generator_test.rb b/test/generators/controllers_generator_test.rb
index 6df0f0c2..01bf970e 100644
--- a/test/generators/controllers_generator_test.rb
+++ b/test/generators/controllers_generator_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "test_helper"
 
 class ControllersGeneratorTest < Rails::Generators::TestCase
diff --git a/test/generators/devise_generator_test.rb b/test/generators/devise_generator_test.rb
index b8824680..00118c22 100644
--- a/test/generators/devise_generator_test.rb
+++ b/test/generators/devise_generator_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'test_helper'
 
 require "generators/devise/devise_generator"
diff --git a/test/generators/install_generator_test.rb b/test/generators/install_generator_test.rb
index daf386d9..45aeddd0 100644
--- a/test/generators/install_generator_test.rb
+++ b/test/generators/install_generator_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "test_helper"
 
 class InstallGeneratorTest < Rails::Generators::TestCase
diff --git a/test/generators/mongoid_generator_test.rb b/test/generators/mongoid_generator_test.rb
index 51802e8e..ea20b4ca 100644
--- a/test/generators/mongoid_generator_test.rb
+++ b/test/generators/mongoid_generator_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "test_helper"
 
 if DEVISE_ORM == :mongoid
diff --git a/test/generators/views_generator_test.rb b/test/generators/views_generator_test.rb
index 7fcdff0d..bfb4a7f1 100644
--- a/test/generators/views_generator_test.rb
+++ b/test/generators/views_generator_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "test_helper"
 
 class ViewsGeneratorTest < Rails::Generators::TestCase
diff --git a/test/helpers/devise_helper_test.rb b/test/helpers/devise_helper_test.rb
index 816d5426..754e82d8 100644
--- a/test/helpers/devise_helper_test.rb
+++ b/test/helpers/devise_helper_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'test_helper'
 
 class DeviseHelperTest < Devise::IntegrationTest
diff --git a/test/integration/authenticatable_test.rb b/test/integration/authenticatable_test.rb
index 6d715b79..4f19f3c8 100644
--- a/test/integration/authenticatable_test.rb
+++ b/test/integration/authenticatable_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'test_helper'
 
 class AuthenticationSanityTest < Devise::IntegrationTest
diff --git a/test/integration/confirmable_test.rb b/test/integration/confirmable_test.rb
index 02730d58..72a28c82 100644
--- a/test/integration/confirmable_test.rb
+++ b/test/integration/confirmable_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'test_helper'
 
 class ConfirmationTest < Devise::IntegrationTest
diff --git a/test/integration/database_authenticatable_test.rb b/test/integration/database_authenticatable_test.rb
index 135f113b..c367ce07 100644
--- a/test/integration/database_authenticatable_test.rb
+++ b/test/integration/database_authenticatable_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'test_helper'
 
 class DatabaseAuthenticationTest < Devise::IntegrationTest
diff --git a/test/integration/http_authenticatable_test.rb b/test/integration/http_authenticatable_test.rb
index 56ea541c..54349f45 100644
--- a/test/integration/http_authenticatable_test.rb
+++ b/test/integration/http_authenticatable_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'test_helper'
 
 class HttpAuthenticationTest < Devise::IntegrationTest
diff --git a/test/integration/lockable_test.rb b/test/integration/lockable_test.rb
index cf6a9001..87e439ef 100644
--- a/test/integration/lockable_test.rb
+++ b/test/integration/lockable_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'test_helper'
 
 class LockTest < Devise::IntegrationTest
diff --git a/test/integration/mounted_engine_test.rb b/test/integration/mounted_engine_test.rb
index 98dcf475..a19d6a22 100644
--- a/test/integration/mounted_engine_test.rb
+++ b/test/integration/mounted_engine_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'test_helper'
 
 class MyMountableEngine
diff --git a/test/integration/omniauthable_test.rb b/test/integration/omniauthable_test.rb
index 6af88420..050b210c 100644
--- a/test/integration/omniauthable_test.rb
+++ b/test/integration/omniauthable_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'test_helper'
 
 
diff --git a/test/integration/recoverable_test.rb b/test/integration/recoverable_test.rb
index f35a46b7..c834f1d2 100644
--- a/test/integration/recoverable_test.rb
+++ b/test/integration/recoverable_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'test_helper'
 
 class PasswordTest < Devise::IntegrationTest
diff --git a/test/integration/registerable_test.rb b/test/integration/registerable_test.rb
index 4fa361b7..2387cd29 100644
--- a/test/integration/registerable_test.rb
+++ b/test/integration/registerable_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'test_helper'
 
 class RegistrationTest < Devise::IntegrationTest
diff --git a/test/integration/rememberable_test.rb b/test/integration/rememberable_test.rb
index 1dfd07d6..193a458e 100644
--- a/test/integration/rememberable_test.rb
+++ b/test/integration/rememberable_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'test_helper'
 
 class RememberMeTest < Devise::IntegrationTest
diff --git a/test/integration/timeoutable_test.rb b/test/integration/timeoutable_test.rb
index d831a96c..ceddd108 100644
--- a/test/integration/timeoutable_test.rb
+++ b/test/integration/timeoutable_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'test_helper'
 
 class SessionTimeoutTest < Devise::IntegrationTest
diff --git a/test/integration/trackable_test.rb b/test/integration/trackable_test.rb
index 4337f153..68d50e11 100644
--- a/test/integration/trackable_test.rb
+++ b/test/integration/trackable_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'test_helper'
 
 class TrackableHooksTest < Devise::IntegrationTest
diff --git a/test/mailers/confirmation_instructions_test.rb b/test/mailers/confirmation_instructions_test.rb
index f929ba43..358b092c 100644
--- a/test/mailers/confirmation_instructions_test.rb
+++ b/test/mailers/confirmation_instructions_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'test_helper'
 
 class ConfirmationInstructionsTest < ActionMailer::TestCase
diff --git a/test/mailers/email_changed_test.rb b/test/mailers/email_changed_test.rb
index f3578297..09717f3c 100644
--- a/test/mailers/email_changed_test.rb
+++ b/test/mailers/email_changed_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'test_helper'
 
 class EmailChangedTest < ActionMailer::TestCase
diff --git a/test/mailers/mailer_test.rb b/test/mailers/mailer_test.rb
index f6ec5d5a..f8369052 100644
--- a/test/mailers/mailer_test.rb
+++ b/test/mailers/mailer_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "test_helper"
 
 class MailerTest < ActionMailer::TestCase
diff --git a/test/mailers/reset_password_instructions_test.rb b/test/mailers/reset_password_instructions_test.rb
index 511cadd3..f0b45809 100644
--- a/test/mailers/reset_password_instructions_test.rb
+++ b/test/mailers/reset_password_instructions_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'test_helper'
 
 class ResetPasswordInstructionsTest < ActionMailer::TestCase
diff --git a/test/mailers/unlock_instructions_test.rb b/test/mailers/unlock_instructions_test.rb
index 32b998f3..586799da 100644
--- a/test/mailers/unlock_instructions_test.rb
+++ b/test/mailers/unlock_instructions_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'test_helper'
 
 class UnlockInstructionsTest < ActionMailer::TestCase
diff --git a/test/mapping_test.rb b/test/mapping_test.rb
index b1010166..0fc10c1a 100644
--- a/test/mapping_test.rb
+++ b/test/mapping_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'test_helper'
 
 class FakeRequest < Struct.new(:path_info, :params)
diff --git a/test/models/authenticatable_test.rb b/test/models/authenticatable_test.rb
index ba664f3e..b3cab65b 100644
--- a/test/models/authenticatable_test.rb
+++ b/test/models/authenticatable_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'test_helper'
 
 class AuthenticatableTest < ActiveSupport::TestCase
diff --git a/test/models/confirmable_test.rb b/test/models/confirmable_test.rb
index e0f08cc0..d0446642 100644
--- a/test/models/confirmable_test.rb
+++ b/test/models/confirmable_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'test_helper'
 
 class ConfirmableTest < ActiveSupport::TestCase
diff --git a/test/models/database_authenticatable_test.rb b/test/models/database_authenticatable_test.rb
index a5c7c77f..fa0de7d0 100644
--- a/test/models/database_authenticatable_test.rb
+++ b/test/models/database_authenticatable_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'test_helper'
 require 'test_models'
 require 'digest/sha1'
diff --git a/test/models/lockable_test.rb b/test/models/lockable_test.rb
index 52373b81..2685afe9 100644
--- a/test/models/lockable_test.rb
+++ b/test/models/lockable_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'test_helper'
 
 class LockableTest < ActiveSupport::TestCase
diff --git a/test/models/omniauthable_test.rb b/test/models/omniauthable_test.rb
index 03e1f688..c22bc430 100644
--- a/test/models/omniauthable_test.rb
+++ b/test/models/omniauthable_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'test_helper'
 
 class OmniauthableTest < ActiveSupport::TestCase
diff --git a/test/models/recoverable_test.rb b/test/models/recoverable_test.rb
index 96b36187..919e6e48 100644
--- a/test/models/recoverable_test.rb
+++ b/test/models/recoverable_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'test_helper'
 
 class RecoverableTest < ActiveSupport::TestCase
diff --git a/test/models/registerable_test.rb b/test/models/registerable_test.rb
index bef6c8ce..25493416 100644
--- a/test/models/registerable_test.rb
+++ b/test/models/registerable_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'test_helper'
 
 class RegisterableTest < ActiveSupport::TestCase
diff --git a/test/models/rememberable_test.rb b/test/models/rememberable_test.rb
index aa9ce817..24ebb3fe 100644
--- a/test/models/rememberable_test.rb
+++ b/test/models/rememberable_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'test_helper'
 
 class RememberableTest < ActiveSupport::TestCase
diff --git a/test/models/serializable_test.rb b/test/models/serializable_test.rb
index 784b51d7..0ec9e720 100644
--- a/test/models/serializable_test.rb
+++ b/test/models/serializable_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'test_helper'
 
 class SerializableTest < ActiveSupport::TestCase
diff --git a/test/models/timeoutable_test.rb b/test/models/timeoutable_test.rb
index 2deac0d3..205c8023 100644
--- a/test/models/timeoutable_test.rb
+++ b/test/models/timeoutable_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'test_helper'
 
 class TimeoutableTest < ActiveSupport::TestCase
diff --git a/test/models/trackable_test.rb b/test/models/trackable_test.rb
index 07ac9802..4685f1ce 100644
--- a/test/models/trackable_test.rb
+++ b/test/models/trackable_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'test_helper'
 
 class TrackableTest < ActiveSupport::TestCase
diff --git a/test/models/validatable_test.rb b/test/models/validatable_test.rb
index 343be9ce..6e02ad44 100644
--- a/test/models/validatable_test.rb
+++ b/test/models/validatable_test.rb
@@ -1,4 +1,6 @@
 # encoding: UTF-8
+# frozen_string_literal: true
+
 require 'test_helper'
 
 class ValidatableTest < ActiveSupport::TestCase
diff --git a/test/models_test.rb b/test/models_test.rb
index 2dc3d9d8..f1e42799 100644
--- a/test/models_test.rb
+++ b/test/models_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'test_helper'
 require 'test_models'
 
diff --git a/test/omniauth/config_test.rb b/test/omniauth/config_test.rb
index d2d0223d..d2bf11bb 100644
--- a/test/omniauth/config_test.rb
+++ b/test/omniauth/config_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'test_helper'
 
 class OmniAuthConfigTest < ActiveSupport::TestCase
diff --git a/test/omniauth/url_helpers_test.rb b/test/omniauth/url_helpers_test.rb
index 21bf9d3a..41d4f501 100644
--- a/test/omniauth/url_helpers_test.rb
+++ b/test/omniauth/url_helpers_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'test_helper'
 
 class OmniAuthRoutesTest < ActionController::TestCase
diff --git a/test/orm/active_record.rb b/test/orm/active_record.rb
index a3afd74e..138c554c 100644
--- a/test/orm/active_record.rb
+++ b/test/orm/active_record.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 ActiveRecord::Migration.verbose = false
 ActiveRecord::Base.logger = Logger.new(nil)
 ActiveRecord::Base.include_root_in_json = true
diff --git a/test/orm/mongoid.rb b/test/orm/mongoid.rb
index 1cbe5ed4..d31bc4d2 100644
--- a/test/orm/mongoid.rb
+++ b/test/orm/mongoid.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'mongoid/version'
 
 Mongoid.configure do |config|
diff --git a/test/parameter_sanitizer_test.rb b/test/parameter_sanitizer_test.rb
index a1f38426..4e89eb9e 100644
--- a/test/parameter_sanitizer_test.rb
+++ b/test/parameter_sanitizer_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'test_helper'
 require 'devise/parameter_sanitizer'
 
diff --git a/test/rails_app/app/active_record/admin.rb b/test/rails_app/app/active_record/admin.rb
index 124bc905..5383b3b2 100644
--- a/test/rails_app/app/active_record/admin.rb
+++ b/test/rails_app/app/active_record/admin.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'shared_admin'
 
 class Admin < ActiveRecord::Base
diff --git a/test/rails_app/app/active_record/shim.rb b/test/rails_app/app/active_record/shim.rb
index 66f12cdb..be35adb9 100644
--- a/test/rails_app/app/active_record/shim.rb
+++ b/test/rails_app/app/active_record/shim.rb
@@ -1,2 +1,4 @@
+# frozen_string_literal: true
+
 module Shim
 end
diff --git a/test/rails_app/app/active_record/user.rb b/test/rails_app/app/active_record/user.rb
index 1c9ebd41..52bb16dd 100644
--- a/test/rails_app/app/active_record/user.rb
+++ b/test/rails_app/app/active_record/user.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'shared_user'
 
 class User < ActiveRecord::Base
diff --git a/test/rails_app/app/active_record/user_on_engine.rb b/test/rails_app/app/active_record/user_on_engine.rb
index 21eb3050..42f233f3 100644
--- a/test/rails_app/app/active_record/user_on_engine.rb
+++ b/test/rails_app/app/active_record/user_on_engine.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'shared_user_without_omniauth'
 
 class UserOnEngine < ActiveRecord::Base
diff --git a/test/rails_app/app/active_record/user_on_main_app.rb b/test/rails_app/app/active_record/user_on_main_app.rb
index 54ef1f80..596bc3b9 100644
--- a/test/rails_app/app/active_record/user_on_main_app.rb
+++ b/test/rails_app/app/active_record/user_on_main_app.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'shared_user_without_omniauth'
 
 class UserOnMainApp < ActiveRecord::Base
diff --git a/test/rails_app/app/active_record/user_with_validations.rb b/test/rails_app/app/active_record/user_with_validations.rb
index abfbe7e0..c396ba88 100644
--- a/test/rails_app/app/active_record/user_with_validations.rb
+++ b/test/rails_app/app/active_record/user_with_validations.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'shared_user'
 
 class UserWithValidations < ActiveRecord::Base
diff --git a/test/rails_app/app/active_record/user_without_email.rb b/test/rails_app/app/active_record/user_without_email.rb
index 9ad58188..62bdb897 100644
--- a/test/rails_app/app/active_record/user_without_email.rb
+++ b/test/rails_app/app/active_record/user_without_email.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "shared_user_without_email"
 
 class UserWithoutEmail < ActiveRecord::Base
diff --git a/test/rails_app/app/controllers/admins/sessions_controller.rb b/test/rails_app/app/controllers/admins/sessions_controller.rb
index 525ca5ef..122e15a7 100644
--- a/test/rails_app/app/controllers/admins/sessions_controller.rb
+++ b/test/rails_app/app/controllers/admins/sessions_controller.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 class Admins::SessionsController < Devise::SessionsController
   def new
     flash[:special] = "Welcome to #{controller_path.inspect} controller!"
diff --git a/test/rails_app/app/controllers/admins_controller.rb b/test/rails_app/app/controllers/admins_controller.rb
index 6b39be19..c732f589 100644
--- a/test/rails_app/app/controllers/admins_controller.rb
+++ b/test/rails_app/app/controllers/admins_controller.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 class AdminsController < ApplicationController
   before_action :authenticate_admin!
 
diff --git a/test/rails_app/app/controllers/application_controller.rb b/test/rails_app/app/controllers/application_controller.rb
index 7adee128..e60ba0c2 100644
--- a/test/rails_app/app/controllers/application_controller.rb
+++ b/test/rails_app/app/controllers/application_controller.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 # Filters added to this controller apply to all controllers in the application.
 # Likewise, all the methods added will be available for all controllers.
 
diff --git a/test/rails_app/app/controllers/application_with_fake_engine.rb b/test/rails_app/app/controllers/application_with_fake_engine.rb
index c77d67f1..652bd2e0 100644
--- a/test/rails_app/app/controllers/application_with_fake_engine.rb
+++ b/test/rails_app/app/controllers/application_with_fake_engine.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 class ApplicationWithFakeEngine < ApplicationController
   private
 
diff --git a/test/rails_app/app/controllers/custom/registrations_controller.rb b/test/rails_app/app/controllers/custom/registrations_controller.rb
index 3864661f..dd0e7a2f 100644
--- a/test/rails_app/app/controllers/custom/registrations_controller.rb
+++ b/test/rails_app/app/controllers/custom/registrations_controller.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 class Custom::RegistrationsController < Devise::RegistrationsController
   def new
     super do |resource|
diff --git a/test/rails_app/app/controllers/home_controller.rb b/test/rails_app/app/controllers/home_controller.rb
index e2a34230..703e9ef8 100644
--- a/test/rails_app/app/controllers/home_controller.rb
+++ b/test/rails_app/app/controllers/home_controller.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 class HomeController < ApplicationController
   def index
   end
diff --git a/test/rails_app/app/controllers/publisher/registrations_controller.rb b/test/rails_app/app/controllers/publisher/registrations_controller.rb
index 7809a363..f7bdaa08 100644
--- a/test/rails_app/app/controllers/publisher/registrations_controller.rb
+++ b/test/rails_app/app/controllers/publisher/registrations_controller.rb
@@ -1,2 +1,4 @@
+# frozen_string_literal: true
+
 class Publisher::RegistrationsController < ApplicationController
 end
diff --git a/test/rails_app/app/controllers/publisher/sessions_controller.rb b/test/rails_app/app/controllers/publisher/sessions_controller.rb
index 2eed1bb0..48ce6859 100644
--- a/test/rails_app/app/controllers/publisher/sessions_controller.rb
+++ b/test/rails_app/app/controllers/publisher/sessions_controller.rb
@@ -1,2 +1,4 @@
+# frozen_string_literal: true
+
 class Publisher::SessionsController < ApplicationController
 end
diff --git a/test/rails_app/app/controllers/users/omniauth_callbacks_controller.rb b/test/rails_app/app/controllers/users/omniauth_callbacks_controller.rb
index 37cf9a8a..98df2957 100644
--- a/test/rails_app/app/controllers/users/omniauth_callbacks_controller.rb
+++ b/test/rails_app/app/controllers/users/omniauth_callbacks_controller.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 class Users::OmniauthCallbacksController < Devise::OmniauthCallbacksController
   def facebook
     data = request.respond_to?(:get_header) ? request.get_header("omniauth.auth") : request.env["omniauth.auth"]
diff --git a/test/rails_app/app/controllers/users_controller.rb b/test/rails_app/app/controllers/users_controller.rb
index 1d2d7494..d02b8844 100644
--- a/test/rails_app/app/controllers/users_controller.rb
+++ b/test/rails_app/app/controllers/users_controller.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 class UsersController < ApplicationController
   prepend_before_action :current_user, only: :exhibit
   before_action :authenticate_user!, except: [:accept, :exhibit]
diff --git a/test/rails_app/app/helpers/application_helper.rb b/test/rails_app/app/helpers/application_helper.rb
index 22a7940e..fc3fb393 100644
--- a/test/rails_app/app/helpers/application_helper.rb
+++ b/test/rails_app/app/helpers/application_helper.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 # Methods added to this helper will be available to all templates in the application.
 module ApplicationHelper
 end
diff --git a/test/rails_app/app/mailers/users/from_proc_mailer.rb b/test/rails_app/app/mailers/users/from_proc_mailer.rb
index 1bff4cac..e3695125 100644
--- a/test/rails_app/app/mailers/users/from_proc_mailer.rb
+++ b/test/rails_app/app/mailers/users/from_proc_mailer.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 class Users::FromProcMailer < Devise::Mailer
   default from: proc { 'custom@example.com' }
 end
diff --git a/test/rails_app/app/mailers/users/mailer.rb b/test/rails_app/app/mailers/users/mailer.rb
index 3342f75a..5962e15d 100644
--- a/test/rails_app/app/mailers/users/mailer.rb
+++ b/test/rails_app/app/mailers/users/mailer.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 class Users::Mailer < Devise::Mailer
   default from: 'custom@example.com'
 end
diff --git a/test/rails_app/app/mailers/users/reply_to_mailer.rb b/test/rails_app/app/mailers/users/reply_to_mailer.rb
index 67ca82cf..4b241d32 100644
--- a/test/rails_app/app/mailers/users/reply_to_mailer.rb
+++ b/test/rails_app/app/mailers/users/reply_to_mailer.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 class Users::ReplyToMailer < Devise::Mailer
   default from: 'custom@example.com'
   default reply_to: 'custom_reply_to@example.com'
diff --git a/test/rails_app/app/mongoid/admin.rb b/test/rails_app/app/mongoid/admin.rb
index d5884cb6..c41ea059 100644
--- a/test/rails_app/app/mongoid/admin.rb
+++ b/test/rails_app/app/mongoid/admin.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'shared_admin'
 
 class Admin
diff --git a/test/rails_app/app/mongoid/shim.rb b/test/rails_app/app/mongoid/shim.rb
index cd48fd40..e5f35782 100644
--- a/test/rails_app/app/mongoid/shim.rb
+++ b/test/rails_app/app/mongoid/shim.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Shim
   extend ::ActiveSupport::Concern
 
diff --git a/test/rails_app/app/mongoid/user.rb b/test/rails_app/app/mongoid/user.rb
index 0a2e5ea1..7dd7dbe3 100644
--- a/test/rails_app/app/mongoid/user.rb
+++ b/test/rails_app/app/mongoid/user.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'shared_user'
 
 class User
diff --git a/test/rails_app/app/mongoid/user_on_engine.rb b/test/rails_app/app/mongoid/user_on_engine.rb
index e68b096f..f63b727b 100644
--- a/test/rails_app/app/mongoid/user_on_engine.rb
+++ b/test/rails_app/app/mongoid/user_on_engine.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'shared_user_without_omniauth'
 
 class UserOnEngine
diff --git a/test/rails_app/app/mongoid/user_on_main_app.rb b/test/rails_app/app/mongoid/user_on_main_app.rb
index a35f2336..92fea262 100644
--- a/test/rails_app/app/mongoid/user_on_main_app.rb
+++ b/test/rails_app/app/mongoid/user_on_main_app.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'shared_user_without_omniauth'
 
 class UserOnMainApp
diff --git a/test/rails_app/app/mongoid/user_with_validations.rb b/test/rails_app/app/mongoid/user_with_validations.rb
index 25dc5a31..c1b73a30 100644
--- a/test/rails_app/app/mongoid/user_with_validations.rb
+++ b/test/rails_app/app/mongoid/user_with_validations.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "shared_user"
 
 class UserWithValidations
diff --git a/test/rails_app/app/mongoid/user_without_email.rb b/test/rails_app/app/mongoid/user_without_email.rb
index f46ab635..b82ea56a 100644
--- a/test/rails_app/app/mongoid/user_without_email.rb
+++ b/test/rails_app/app/mongoid/user_without_email.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "shared_user_without_email"
 
 class UserWithoutEmail
diff --git a/test/rails_app/config/application.rb b/test/rails_app/config/application.rb
index 34732d0a..19f44e41 100644
--- a/test/rails_app/config/application.rb
+++ b/test/rails_app/config/application.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require File.expand_path('../boot', __FILE__)
 
 require "action_controller/railtie"
diff --git a/test/rails_app/config/boot.rb b/test/rails_app/config/boot.rb
index 60b90730..07fe8daa 100644
--- a/test/rails_app/config/boot.rb
+++ b/test/rails_app/config/boot.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 unless defined?(DEVISE_ORM)
   DEVISE_ORM = (ENV["DEVISE_ORM"] || :active_record).to_sym
 end
diff --git a/test/rails_app/config/environment.rb b/test/rails_app/config/environment.rb
index 1fe685fd..1c7a3ec2 100644
--- a/test/rails_app/config/environment.rb
+++ b/test/rails_app/config/environment.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 # Load the rails application.
 require File.expand_path('../application', __FILE__)
 
diff --git a/test/rails_app/config/environments/development.rb b/test/rails_app/config/environments/development.rb
index fcddb5f5..d23c88d1 100644
--- a/test/rails_app/config/environments/development.rb
+++ b/test/rails_app/config/environments/development.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 RailsApp::Application.configure do
   # Settings specified here will take precedence over those in config/application.rb.
 
diff --git a/test/rails_app/config/environments/production.rb b/test/rails_app/config/environments/production.rb
index bb2d0504..3e62a174 100644
--- a/test/rails_app/config/environments/production.rb
+++ b/test/rails_app/config/environments/production.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 RailsApp::Application.configure do
   # Settings specified here will take precedence over those in config/application.rb.
 
diff --git a/test/rails_app/config/environments/test.rb b/test/rails_app/config/environments/test.rb
index 14732973..b202bc3e 100644
--- a/test/rails_app/config/environments/test.rb
+++ b/test/rails_app/config/environments/test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 RailsApp::Application.configure do
   # Settings specified here will take precedence over those in config/application.rb.
 
diff --git a/test/rails_app/config/initializers/backtrace_silencers.rb b/test/rails_app/config/initializers/backtrace_silencers.rb
index 56ddc8da..9edabe93 100644
--- a/test/rails_app/config/initializers/backtrace_silencers.rb
+++ b/test/rails_app/config/initializers/backtrace_silencers.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 # Be sure to restart your server when you modify this file.
 
 # You can add backtrace silencers for libraries that you're using but don't wish to see in your backtraces.
diff --git a/test/rails_app/config/initializers/devise.rb b/test/rails_app/config/initializers/devise.rb
index d79e71f5..761e398a 100644
--- a/test/rails_app/config/initializers/devise.rb
+++ b/test/rails_app/config/initializers/devise.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "omniauth-facebook"
 require "omniauth-openid"
 
diff --git a/test/rails_app/config/initializers/inflections.rb b/test/rails_app/config/initializers/inflections.rb
index 45fc8f45..7bb3dc01 100644
--- a/test/rails_app/config/initializers/inflections.rb
+++ b/test/rails_app/config/initializers/inflections.rb
@@ -1,2 +1,4 @@
+# frozen_string_literal: true
+
 ActiveSupport::Inflector.inflections do |inflect|
 end
diff --git a/test/rails_app/config/initializers/secret_token.rb b/test/rails_app/config/initializers/secret_token.rb
index 35818fa1..48d1b70a 100644
--- a/test/rails_app/config/initializers/secret_token.rb
+++ b/test/rails_app/config/initializers/secret_token.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 config = Rails.application.config
 
 config.secret_key_base = 'd588e99efff13a86461fd6ab82327823ad2f8feb5dc217ce652cdd9f0dfc5eb4b5a62a92d24d2574d7d51dfb1ea8dd453ea54e00cf672159a13104a135422a10'
diff --git a/test/rails_app/config/initializers/session_store.rb b/test/rails_app/config/initializers/session_store.rb
index 5ac94e7e..5cfac4ec 100644
--- a/test/rails_app/config/initializers/session_store.rb
+++ b/test/rails_app/config/initializers/session_store.rb
@@ -1 +1,3 @@
+# frozen_string_literal: true
+
 RailsApp::Application.config.session_store :cookie_store, key: '_rails_app_session'
diff --git a/test/rails_app/config/routes.rb b/test/rails_app/config/routes.rb
index fb33154f..8687dae2 100644
--- a/test/rails_app/config/routes.rb
+++ b/test/rails_app/config/routes.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 Rails.application.routes.draw do
   # Resources for testing
   resources :users, only: [:index] do
diff --git a/test/rails_app/db/migrate/20100401102949_create_tables.rb b/test/rails_app/db/migrate/20100401102949_create_tables.rb
index 4eecbc2c..43c6d867 100644
--- a/test/rails_app/db/migrate/20100401102949_create_tables.rb
+++ b/test/rails_app/db/migrate/20100401102949_create_tables.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 superclass = ActiveRecord::Migration
 # TODO: Inherit from the 5.0 Migration class directly when we drop support for Rails 4.
 superclass = ActiveRecord::Migration[5.0] if superclass.respond_to?(:[])
diff --git a/test/rails_app/db/schema.rb b/test/rails_app/db/schema.rb
index a7446056..c435f6b9 100644
--- a/test/rails_app/db/schema.rb
+++ b/test/rails_app/db/schema.rb
@@ -1,4 +1,6 @@
 # encoding: UTF-8
+# frozen_string_literal: true
+
 # This file is auto-generated from the current state of the database. Instead
 # of editing this file, please use the migrations feature of Active Record to
 # incrementally modify your database, and then regenerate this schema definition.
diff --git a/test/rails_app/lib/shared_admin.rb b/test/rails_app/lib/shared_admin.rb
index 7d6227a3..3e6362a7 100644
--- a/test/rails_app/lib/shared_admin.rb
+++ b/test/rails_app/lib/shared_admin.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module SharedAdmin
   extend ActiveSupport::Concern
 
diff --git a/test/rails_app/lib/shared_user.rb b/test/rails_app/lib/shared_user.rb
index c3b023a4..e037fe86 100644
--- a/test/rails_app/lib/shared_user.rb
+++ b/test/rails_app/lib/shared_user.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module SharedUser
   extend ActiveSupport::Concern
 
diff --git a/test/rails_app/lib/shared_user_without_email.rb b/test/rails_app/lib/shared_user_without_email.rb
index cc0a4045..f030c195 100644
--- a/test/rails_app/lib/shared_user_without_email.rb
+++ b/test/rails_app/lib/shared_user_without_email.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module SharedUserWithoutEmail
   extend ActiveSupport::Concern
 
diff --git a/test/rails_app/lib/shared_user_without_omniauth.rb b/test/rails_app/lib/shared_user_without_omniauth.rb
index 7f0396c0..7b9ae08f 100644
--- a/test/rails_app/lib/shared_user_without_omniauth.rb
+++ b/test/rails_app/lib/shared_user_without_omniauth.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module SharedUserWithoutOmniauth
   extend ActiveSupport::Concern
 
diff --git a/test/rails_test.rb b/test/rails_test.rb
index 65cba2eb..fdc1612e 100644
--- a/test/rails_test.rb
+++ b/test/rails_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'test_helper'
 
 class RailsTest < ActiveSupport::TestCase
diff --git a/test/routes_test.rb b/test/routes_test.rb
index 84229f25..ba580f5b 100644
--- a/test/routes_test.rb
+++ b/test/routes_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'test_helper'
 
 ExpectedRoutingError = MiniTest::Assertion
diff --git a/test/support/action_controller/record_identifier.rb b/test/support/action_controller/record_identifier.rb
index 89b3483e..3d6c61e8 100644
--- a/test/support/action_controller/record_identifier.rb
+++ b/test/support/action_controller/record_identifier.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 # Since webrat uses ActionController::RecordIdentifier class that was moved to
 # ActionView namespace in Rails 4.1+
 
diff --git a/test/support/assertions.rb b/test/support/assertions.rb
index 7ec8b323..9872a0ae 100644
--- a/test/support/assertions.rb
+++ b/test/support/assertions.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'active_support/test_case'
 
 class ActiveSupport::TestCase
diff --git a/test/support/helpers.rb b/test/support/helpers.rb
index db82dd7c..fe7cf1b5 100644
--- a/test/support/helpers.rb
+++ b/test/support/helpers.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'active_support/test_case'
 
 class ActiveSupport::TestCase
diff --git a/test/support/http_method_compatibility.rb b/test/support/http_method_compatibility.rb
index 7b8fdf08..87946314 100644
--- a/test/support/http_method_compatibility.rb
+++ b/test/support/http_method_compatibility.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Devise
   class IntegrationTest < ActionDispatch::IntegrationTest
     # %w( get post patch put head delete xml_http_request
diff --git a/test/support/integration.rb b/test/support/integration.rb
index ac140e86..ea6792a7 100644
--- a/test/support/integration.rb
+++ b/test/support/integration.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'action_dispatch/testing/integration'
 
 class ActionDispatch::IntegrationTest
diff --git a/test/support/webrat/integrations/rails.rb b/test/support/webrat/integrations/rails.rb
index 6f4aedcf..ebb481a1 100644
--- a/test/support/webrat/integrations/rails.rb
+++ b/test/support/webrat/integrations/rails.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'webrat/core/elements/form'
 require 'action_dispatch/testing/integration'
 
diff --git a/test/test/controller_helpers_test.rb b/test/test/controller_helpers_test.rb
index e94ce309..6c14c189 100644
--- a/test/test/controller_helpers_test.rb
+++ b/test/test/controller_helpers_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'test_helper'
 
 class TestControllerHelpersTest < Devise::ControllerTestCase
diff --git a/test/test/integration_helpers_test.rb b/test/test/integration_helpers_test.rb
index 5f7dfd31..131593c1 100644
--- a/test/test/integration_helpers_test.rb
+++ b/test/test/integration_helpers_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'test_helper'
 
 class TestIntegrationsHelpersTest < Devise::IntegrationTest
diff --git a/test/test_helper.rb b/test/test_helper.rb
index 9f36b488..cfd925d5 100644
--- a/test/test_helper.rb
+++ b/test/test_helper.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 ENV["RAILS_ENV"] = "test"
 DEVISE_ORM = (ENV["DEVISE_ORM"] || :active_record).to_sym
 
diff --git a/test/test_models.rb b/test/test_models.rb
index d65648d9..0e52bef4 100644
--- a/test/test_models.rb
+++ b/test/test_models.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 class Configurable < User
   devise :database_authenticatable, :confirmable, :rememberable, :timeoutable, :lockable,
          stretches: 15, pepper: 'abcdef', allow_unconfirmed_access_for: 5.days,