Merge remote-tracking branch 'origin/master' into unlock-minitest

116 files changed, 247 insertions, 11 deletions

diff --git a/activemodel/Rakefile b/activemodel/Rakefile
index d60f6d9997..d39f50a962 100644
--- a/activemodel/Rakefile
+++ b/activemodel/Rakefile
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "rake/testtask"
 
 task default: :test
diff --git a/activemodel/activemodel.gemspec b/activemodel/activemodel.gemspec
index 18a35678f1..a070a2898c 100644
--- a/activemodel/activemodel.gemspec
+++ b/activemodel/activemodel.gemspec
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 version = File.read(File.expand_path("../RAILS_VERSION", __dir__)).strip
 
 Gem::Specification.new do |s|
diff --git a/activemodel/bin/test b/activemodel/bin/test
index 470ce93f10..c53377cc97 100755
--- a/activemodel/bin/test
+++ b/activemodel/bin/test
@@ -1,4 +1,5 @@
 #!/usr/bin/env ruby
+# frozen_string_literal: true
 
 COMPONENT_ROOT = File.expand_path("..", __dir__)
 require_relative "../../tools/test"
diff --git a/activemodel/lib/active_model.rb b/activemodel/lib/active_model.rb
index ba1d2fbd44..dfd9be34a9 100644
--- a/activemodel/lib/active_model.rb
+++ b/activemodel/lib/active_model.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 #--
 # Copyright (c) 2004-2017 David Heinemeier Hansson
 #
diff --git a/activemodel/lib/active_model/attribute_methods.rb b/activemodel/lib/active_model/attribute_methods.rb
index b3b39bf7ae..888a431e5f 100644
--- a/activemodel/lib/active_model/attribute_methods.rb
+++ b/activemodel/lib/active_model/attribute_methods.rb
@@ -1,5 +1,6 @@
+# frozen_string_literal: true
+
 require "concurrent/map"
-require "mutex_m"
 
 module ActiveModel
   # Raised when an attribute is not defined.
@@ -327,13 +328,11 @@ module ActiveModel
         attribute_method_matchers_cache.clear
       end
 
-      def generated_attribute_methods #:nodoc:
-        @generated_attribute_methods ||= Module.new {
-          extend Mutex_m
-        }.tap { |mod| include mod }
-      end
-
       private
+        def generated_attribute_methods
+          @generated_attribute_methods ||= Module.new.tap { |mod| include mod }
+        end
+
         def instance_method_already_implemented?(method_name)
           generated_attribute_methods.method_defined?(method_name)
         end
diff --git a/activemodel/lib/active_model/callbacks.rb b/activemodel/lib/active_model/callbacks.rb
index 835e6f7716..5768eec7f5 100644
--- a/activemodel/lib/active_model/callbacks.rb
+++ b/activemodel/lib/active_model/callbacks.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "active_support/core_ext/array/extract_options"
 
 module ActiveModel
diff --git a/activemodel/lib/active_model/conversion.rb b/activemodel/lib/active_model/conversion.rb
index 12687c70d3..cdc1282817 100644
--- a/activemodel/lib/active_model/conversion.rb
+++ b/activemodel/lib/active_model/conversion.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActiveModel
   # == Active \Model \Conversion
   #
diff --git a/activemodel/lib/active_model/dirty.rb b/activemodel/lib/active_model/dirty.rb
index dc81f74779..943db0ab52 100644
--- a/activemodel/lib/active_model/dirty.rb
+++ b/activemodel/lib/active_model/dirty.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "active_support/hash_with_indifferent_access"
 require "active_support/core_ext/object/duplicable"
 
diff --git a/activemodel/lib/active_model/errors.rb b/activemodel/lib/active_model/errors.rb
index 76c23df541..c24ae4e430 100644
--- a/activemodel/lib/active_model/errors.rb
+++ b/activemodel/lib/active_model/errors.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "active_support/core_ext/array/conversions"
 require "active_support/core_ext/string/inflections"
 require "active_support/core_ext/object/deep_dup"
diff --git a/activemodel/lib/active_model/forbidden_attributes_protection.rb b/activemodel/lib/active_model/forbidden_attributes_protection.rb
index 45ab8a2ca1..4b37f80c52 100644
--- a/activemodel/lib/active_model/forbidden_attributes_protection.rb
+++ b/activemodel/lib/active_model/forbidden_attributes_protection.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActiveModel
   # Raised when forbidden attributes are used for mass assignment.
   #
diff --git a/activemodel/lib/active_model/gem_version.rb b/activemodel/lib/active_model/gem_version.rb
index 67bdfaa643..39269c159c 100644
--- a/activemodel/lib/active_model/gem_version.rb
+++ b/activemodel/lib/active_model/gem_version.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActiveModel
   # Returns the version of the currently loaded \Active \Model as a <tt>Gem::Version</tt>
   def self.gem_version
diff --git a/activemodel/lib/active_model/lint.rb b/activemodel/lib/active_model/lint.rb
index 291a545528..34d9ac6c96 100644
--- a/activemodel/lib/active_model/lint.rb
+++ b/activemodel/lib/active_model/lint.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActiveModel
   module Lint
     # == Active \Model \Lint \Tests
diff --git a/activemodel/lib/active_model/model.rb b/activemodel/lib/active_model/model.rb
index 945a5402a3..fc52cd4fdf 100644
--- a/activemodel/lib/active_model/model.rb
+++ b/activemodel/lib/active_model/model.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActiveModel
   # == Active \Model \Basic \Model
   #
diff --git a/activemodel/lib/active_model/naming.rb b/activemodel/lib/active_model/naming.rb
index 9ac56526a2..a09659ad77 100644
--- a/activemodel/lib/active_model/naming.rb
+++ b/activemodel/lib/active_model/naming.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "active_support/core_ext/hash/except"
 require "active_support/core_ext/module/introspection"
 require "active_support/core_ext/module/remove_method"
diff --git a/activemodel/lib/active_model/railtie.rb b/activemodel/lib/active_model/railtie.rb
index 1671eb7bd4..a9cdabba00 100644
--- a/activemodel/lib/active_model/railtie.rb
+++ b/activemodel/lib/active_model/railtie.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "active_model"
 require "rails"
 
diff --git a/activemodel/lib/active_model/secure_password.rb b/activemodel/lib/active_model/secure_password.rb
index 1c0fe92bc0..86f051f5ce 100644
--- a/activemodel/lib/active_model/secure_password.rb
+++ b/activemodel/lib/active_model/secure_password.rb
@@ -1,9 +1,11 @@
+# frozen_string_literal: true
+
 module ActiveModel
   module SecurePassword
     extend ActiveSupport::Concern
 
-    # BCrypt hash function can handle maximum 72 characters, and if we pass
-    # password of length more than 72 characters it ignores extra characters.
+    # BCrypt hash function can handle maximum 72 bytes, and if we pass
+    # password of length more than 72 bytes it ignores extra characters.
     # Hence need to put a restriction on password length.
     MAX_PASSWORD_LENGTH_ALLOWED = 72
 
@@ -18,7 +20,7 @@ module ActiveModel
       #
       # The following validations are added automatically:
       # * Password must be present on creation
-      # * Password length should be less than or equal to 72 characters
+      # * Password length should be less than or equal to 72 bytes
       # * Confirmation of password (using a +password_confirmation+ attribute)
       #
       # If password confirmation validation is not needed, simply leave out the
diff --git a/activemodel/lib/active_model/serialization.rb b/activemodel/lib/active_model/serialization.rb
index 77834f26fc..47cb81bee5 100644
--- a/activemodel/lib/active_model/serialization.rb
+++ b/activemodel/lib/active_model/serialization.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "active_support/core_ext/hash/except"
 require "active_support/core_ext/hash/slice"
 
diff --git a/activemodel/lib/active_model/serializers/json.rb b/activemodel/lib/active_model/serializers/json.rb
index 205b84ddb4..25e1541d66 100644
--- a/activemodel/lib/active_model/serializers/json.rb
+++ b/activemodel/lib/active_model/serializers/json.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "active_support/json"
 
 module ActiveModel
diff --git a/activemodel/lib/active_model/translation.rb b/activemodel/lib/active_model/translation.rb
index 35fc7cf743..f3d0d3dc27 100644
--- a/activemodel/lib/active_model/translation.rb
+++ b/activemodel/lib/active_model/translation.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActiveModel
   # == Active \Model \Translation
   #
diff --git a/activemodel/lib/active_model/type.rb b/activemodel/lib/active_model/type.rb
index 1741a67a4d..cb603b3d25 100644
--- a/activemodel/lib/active_model/type.rb
+++ b/activemodel/lib/active_model/type.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require_relative "type/helpers"
 require_relative "type/value"
 
diff --git a/activemodel/lib/active_model/type/big_integer.rb b/activemodel/lib/active_model/type/big_integer.rb
index f461d7041e..d080fcc0f2 100644
--- a/activemodel/lib/active_model/type/big_integer.rb
+++ b/activemodel/lib/active_model/type/big_integer.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require_relative "integer"
 
 module ActiveModel
diff --git a/activemodel/lib/active_model/type/binary.rb b/activemodel/lib/active_model/type/binary.rb
index 819e4e4a96..dc2eca18be 100644
--- a/activemodel/lib/active_model/type/binary.rb
+++ b/activemodel/lib/active_model/type/binary.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActiveModel
   module Type
     class Binary < Value # :nodoc:
diff --git a/activemodel/lib/active_model/type/boolean.rb b/activemodel/lib/active_model/type/boolean.rb
index f2a47370a3..bcdbab0343 100644
--- a/activemodel/lib/active_model/type/boolean.rb
+++ b/activemodel/lib/active_model/type/boolean.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActiveModel
   module Type
     # == Active \Model \Type \Boolean
diff --git a/activemodel/lib/active_model/type/date.rb b/activemodel/lib/active_model/type/date.rb
index eefd080351..8cecc16d0f 100644
--- a/activemodel/lib/active_model/type/date.rb
+++ b/activemodel/lib/active_model/type/date.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActiveModel
   module Type
     class Date < Value # :nodoc:
diff --git a/activemodel/lib/active_model/type/date_time.rb b/activemodel/lib/active_model/type/date_time.rb
index 8ad0daa9a6..9641bf45ee 100644
--- a/activemodel/lib/active_model/type/date_time.rb
+++ b/activemodel/lib/active_model/type/date_time.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActiveModel
   module Type
     class DateTime < Value # :nodoc:
diff --git a/activemodel/lib/active_model/type/decimal.rb b/activemodel/lib/active_model/type/decimal.rb
index e6805c5f6b..e8ee18c00e 100644
--- a/activemodel/lib/active_model/type/decimal.rb
+++ b/activemodel/lib/active_model/type/decimal.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "bigdecimal/util"
 
 module ActiveModel
diff --git a/activemodel/lib/active_model/type/float.rb b/activemodel/lib/active_model/type/float.rb
index 4d0d2771a0..9dbe32e5a6 100644
--- a/activemodel/lib/active_model/type/float.rb
+++ b/activemodel/lib/active_model/type/float.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActiveModel
   module Type
     class Float < Value # :nodoc:
diff --git a/activemodel/lib/active_model/type/helpers.rb b/activemodel/lib/active_model/type/helpers.rb
index 1fe06ab3d5..a4e1427b64 100644
--- a/activemodel/lib/active_model/type/helpers.rb
+++ b/activemodel/lib/active_model/type/helpers.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require_relative "helpers/accepts_multiparameter_time"
 require_relative "helpers/numeric"
 require_relative "helpers/mutable"
diff --git a/activemodel/lib/active_model/type/helpers/accepts_multiparameter_time.rb b/activemodel/lib/active_model/type/helpers/accepts_multiparameter_time.rb
index f783d286c5..ad891f841e 100644
--- a/activemodel/lib/active_model/type/helpers/accepts_multiparameter_time.rb
+++ b/activemodel/lib/active_model/type/helpers/accepts_multiparameter_time.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActiveModel
   module Type
     module Helpers # :nodoc: all
@@ -19,6 +21,10 @@ module ActiveModel
             end
           end
 
+          define_method(:value_constructed_by_mass_assignment?) do |value|
+            value.is_a?(Hash)
+          end
+
           define_method(:value_from_multiparameter_assignment) do |values_hash|
             defaults.each do |k, v|
               values_hash[k] ||= v
diff --git a/activemodel/lib/active_model/type/helpers/mutable.rb b/activemodel/lib/active_model/type/helpers/mutable.rb
index f3a17a1698..1cbea644c4 100644
--- a/activemodel/lib/active_model/type/helpers/mutable.rb
+++ b/activemodel/lib/active_model/type/helpers/mutable.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActiveModel
   module Type
     module Helpers # :nodoc: all
diff --git a/activemodel/lib/active_model/type/helpers/numeric.rb b/activemodel/lib/active_model/type/helpers/numeric.rb
index 275822b738..16e14f9e5f 100644
--- a/activemodel/lib/active_model/type/helpers/numeric.rb
+++ b/activemodel/lib/active_model/type/helpers/numeric.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActiveModel
   module Type
     module Helpers # :nodoc: all
diff --git a/activemodel/lib/active_model/type/helpers/time_value.rb b/activemodel/lib/active_model/type/helpers/time_value.rb
index 53cf7c6029..250c4021c6 100644
--- a/activemodel/lib/active_model/type/helpers/time_value.rb
+++ b/activemodel/lib/active_model/type/helpers/time_value.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "active_support/core_ext/time/zones"
 
 module ActiveModel
diff --git a/activemodel/lib/active_model/type/immutable_string.rb b/activemodel/lib/active_model/type/immutable_string.rb
index 58268540e5..826bd7038f 100644
--- a/activemodel/lib/active_model/type/immutable_string.rb
+++ b/activemodel/lib/active_model/type/immutable_string.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActiveModel
   module Type
     class ImmutableString < Value # :nodoc:
diff --git a/activemodel/lib/active_model/type/integer.rb b/activemodel/lib/active_model/type/integer.rb
index 106b5d966c..d1473bd792 100644
--- a/activemodel/lib/active_model/type/integer.rb
+++ b/activemodel/lib/active_model/type/integer.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActiveModel
   module Type
     class Integer < Value # :nodoc:
diff --git a/activemodel/lib/active_model/type/registry.rb b/activemodel/lib/active_model/type/registry.rb
index 2d5dd366eb..7272d7b0c5 100644
--- a/activemodel/lib/active_model/type/registry.rb
+++ b/activemodel/lib/active_model/type/registry.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActiveModel
   # :stopdoc:
   module Type
diff --git a/activemodel/lib/active_model/type/string.rb b/activemodel/lib/active_model/type/string.rb
index 2fc027d3c4..6ba2c2a3d2 100644
--- a/activemodel/lib/active_model/type/string.rb
+++ b/activemodel/lib/active_model/type/string.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require_relative "immutable_string"
 
 module ActiveModel
diff --git a/activemodel/lib/active_model/type/time.rb b/activemodel/lib/active_model/type/time.rb
index 54d6214e81..ad7ba0351a 100644
--- a/activemodel/lib/active_model/type/time.rb
+++ b/activemodel/lib/active_model/type/time.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActiveModel
   module Type
     class Time < Value # :nodoc:
diff --git a/activemodel/lib/active_model/type/value.rb b/activemodel/lib/active_model/type/value.rb
index 7e9ae92245..a8ea6a2c22 100644
--- a/activemodel/lib/active_model/type/value.rb
+++ b/activemodel/lib/active_model/type/value.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActiveModel
   module Type
     class Value
@@ -84,6 +86,10 @@ module ActiveModel
         false
       end
 
+      def value_constructed_by_mass_assignment?(_value) # :nodoc:
+        false
+      end
+
       def map(value) # :nodoc:
         yield value
       end
diff --git a/activemodel/lib/active_model/validations.rb b/activemodel/lib/active_model/validations.rb
index ae1d69f685..cdf11d190f 100644
--- a/activemodel/lib/active_model/validations.rb
+++ b/activemodel/lib/active_model/validations.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "active_support/core_ext/array/extract_options"
 require "active_support/core_ext/hash/keys"
 require "active_support/core_ext/hash/except"
diff --git a/activemodel/lib/active_model/validations/absence.rb b/activemodel/lib/active_model/validations/absence.rb
index 4618f46e30..385d9f27e0 100644
--- a/activemodel/lib/active_model/validations/absence.rb
+++ b/activemodel/lib/active_model/validations/absence.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActiveModel
   module Validations
     # == \Active \Model Absence Validator
diff --git a/activemodel/lib/active_model/validations/acceptance.rb b/activemodel/lib/active_model/validations/acceptance.rb
index a26c37daa5..f35e4dec7f 100644
--- a/activemodel/lib/active_model/validations/acceptance.rb
+++ b/activemodel/lib/active_model/validations/acceptance.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActiveModel
   module Validations
     class AcceptanceValidator < EachValidator # :nodoc:
diff --git a/activemodel/lib/active_model/validations/callbacks.rb b/activemodel/lib/active_model/validations/callbacks.rb
index 4e94422cf1..4d0ab2a2fe 100644
--- a/activemodel/lib/active_model/validations/callbacks.rb
+++ b/activemodel/lib/active_model/validations/callbacks.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActiveModel
   module Validations
     # == Active \Model \Validation \Callbacks
diff --git a/activemodel/lib/active_model/validations/clusivity.rb b/activemodel/lib/active_model/validations/clusivity.rb
index 18f1056e2b..0b9b5ce6a1 100644
--- a/activemodel/lib/active_model/validations/clusivity.rb
+++ b/activemodel/lib/active_model/validations/clusivity.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "active_support/core_ext/range"
 
 module ActiveModel
diff --git a/activemodel/lib/active_model/validations/confirmation.rb b/activemodel/lib/active_model/validations/confirmation.rb
index 03585bf5e1..0abec56b68 100644
--- a/activemodel/lib/active_model/validations/confirmation.rb
+++ b/activemodel/lib/active_model/validations/confirmation.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActiveModel
   module Validations
     class ConfirmationValidator < EachValidator # :nodoc:
diff --git a/activemodel/lib/active_model/validations/exclusion.rb b/activemodel/lib/active_model/validations/exclusion.rb
index d587079bd3..a6cbfcc813 100644
--- a/activemodel/lib/active_model/validations/exclusion.rb
+++ b/activemodel/lib/active_model/validations/exclusion.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require_relative "clusivity"
 
 module ActiveModel
diff --git a/activemodel/lib/active_model/validations/format.rb b/activemodel/lib/active_model/validations/format.rb
index 98b3f6a8e5..7c3f091473 100644
--- a/activemodel/lib/active_model/validations/format.rb
+++ b/activemodel/lib/active_model/validations/format.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActiveModel
   module Validations
     class FormatValidator < EachValidator # :nodoc:
diff --git a/activemodel/lib/active_model/validations/helper_methods.rb b/activemodel/lib/active_model/validations/helper_methods.rb
index 2176115334..730173f2f9 100644
--- a/activemodel/lib/active_model/validations/helper_methods.rb
+++ b/activemodel/lib/active_model/validations/helper_methods.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActiveModel
   module Validations
     module HelperMethods # :nodoc:
diff --git a/activemodel/lib/active_model/validations/inclusion.rb b/activemodel/lib/active_model/validations/inclusion.rb
index 74dac3b7df..00e27b528a 100644
--- a/activemodel/lib/active_model/validations/inclusion.rb
+++ b/activemodel/lib/active_model/validations/inclusion.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require_relative "clusivity"
 
 module ActiveModel
diff --git a/activemodel/lib/active_model/validations/length.rb b/activemodel/lib/active_model/validations/length.rb
index 940c58f3a7..d1a4197286 100644
--- a/activemodel/lib/active_model/validations/length.rb
+++ b/activemodel/lib/active_model/validations/length.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActiveModel
   module Validations
     class LengthValidator < EachValidator # :nodoc:
diff --git a/activemodel/lib/active_model/validations/numericality.rb b/activemodel/lib/active_model/validations/numericality.rb
index fb053a4c4e..31750ba78e 100644
--- a/activemodel/lib/active_model/validations/numericality.rb
+++ b/activemodel/lib/active_model/validations/numericality.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActiveModel
   module Validations
     class NumericalityValidator < EachValidator # :nodoc:
diff --git a/activemodel/lib/active_model/validations/presence.rb b/activemodel/lib/active_model/validations/presence.rb
index ce4106a5e1..8787a75afa 100644
--- a/activemodel/lib/active_model/validations/presence.rb
+++ b/activemodel/lib/active_model/validations/presence.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActiveModel
   module Validations
     class PresenceValidator < EachValidator # :nodoc:
diff --git a/activemodel/lib/active_model/validations/validates.rb b/activemodel/lib/active_model/validations/validates.rb
index a8b958e974..43d9f82d9f 100644
--- a/activemodel/lib/active_model/validations/validates.rb
+++ b/activemodel/lib/active_model/validations/validates.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "active_support/core_ext/hash/slice"
 
 module ActiveModel
diff --git a/activemodel/lib/active_model/validations/with.rb b/activemodel/lib/active_model/validations/with.rb
index 9227dd06ff..d777ac836e 100644
--- a/activemodel/lib/active_model/validations/with.rb
+++ b/activemodel/lib/active_model/validations/with.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "active_support/core_ext/array/extract_options"
 
 module ActiveModel
diff --git a/activemodel/lib/active_model/validator.rb b/activemodel/lib/active_model/validator.rb
index 6c11981e1d..e17c3ca7b3 100644
--- a/activemodel/lib/active_model/validator.rb
+++ b/activemodel/lib/active_model/validator.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "active_support/core_ext/module/anonymous"
 
 module ActiveModel
diff --git a/activemodel/lib/active_model/version.rb b/activemodel/lib/active_model/version.rb
index 6e7fd227fd..dd817f5639 100644
--- a/activemodel/lib/active_model/version.rb
+++ b/activemodel/lib/active_model/version.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require_relative "gem_version"
 
 module ActiveModel
diff --git a/activemodel/test/cases/attribute_assignment_test.rb b/activemodel/test/cases/attribute_assignment_test.rb
index fa41d1b95f..5ecf0a69c4 100644
--- a/activemodel/test/cases/attribute_assignment_test.rb
+++ b/activemodel/test/cases/attribute_assignment_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "cases/helper"
 require "active_support/core_ext/hash/indifferent_access"
 require "active_support/hash_with_indifferent_access"
diff --git a/activemodel/test/cases/attribute_methods_test.rb b/activemodel/test/cases/attribute_methods_test.rb
index 4767accb7c..d2837ec894 100644
--- a/activemodel/test/cases/attribute_methods_test.rb
+++ b/activemodel/test/cases/attribute_methods_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "cases/helper"
 
 class ModelWithAttributes
@@ -116,7 +118,7 @@ class AttributeMethodsTest < ActiveModel::TestCase
 
   test "#define_attribute_method does not generate attribute method if already defined in attribute module" do
     klass = Class.new(ModelWithAttributes)
-    klass.generated_attribute_methods.module_eval do
+    klass.send(:generated_attribute_methods).module_eval do
       def foo
         "<3"
       end
diff --git a/activemodel/test/cases/callbacks_test.rb b/activemodel/test/cases/callbacks_test.rb
index f85cd7dec4..a5d29d0f22 100644
--- a/activemodel/test/cases/callbacks_test.rb
+++ b/activemodel/test/cases/callbacks_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "cases/helper"
 
 class CallbacksTest < ActiveModel::TestCase
diff --git a/activemodel/test/cases/conversion_test.rb b/activemodel/test/cases/conversion_test.rb
index 4a93347abc..347896ed50 100644
--- a/activemodel/test/cases/conversion_test.rb
+++ b/activemodel/test/cases/conversion_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "cases/helper"
 require "models/contact"
 require "models/helicopter"
diff --git a/activemodel/test/cases/dirty_test.rb b/activemodel/test/cases/dirty_test.rb
index 0242b96083..2cd9e185e6 100644
--- a/activemodel/test/cases/dirty_test.rb
+++ b/activemodel/test/cases/dirty_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "cases/helper"
 
 class DirtyTest < ActiveModel::TestCase
diff --git a/activemodel/test/cases/errors_test.rb b/activemodel/test/cases/errors_test.rb
index 7383b3e9b0..ab18af0de1 100644
--- a/activemodel/test/cases/errors_test.rb
+++ b/activemodel/test/cases/errors_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "cases/helper"
 require "active_support/core_ext/string/strip"
 require "yaml"
diff --git a/activemodel/test/cases/forbidden_attributes_protection_test.rb b/activemodel/test/cases/forbidden_attributes_protection_test.rb
index d8cc72e662..0fd0a2f8ee 100644
--- a/activemodel/test/cases/forbidden_attributes_protection_test.rb
+++ b/activemodel/test/cases/forbidden_attributes_protection_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "cases/helper"
 require "active_support/core_ext/hash/indifferent_access"
 require "models/account"
diff --git a/activemodel/test/cases/helper.rb b/activemodel/test/cases/helper.rb
index eeb5c85a48..91fb9d0a7c 100644
--- a/activemodel/test/cases/helper.rb
+++ b/activemodel/test/cases/helper.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "active_model"
 
 # Show backtraces for deprecated behavior for quicker cleanup.
diff --git a/activemodel/test/cases/lint_test.rb b/activemodel/test/cases/lint_test.rb
index 7a817d7c01..d62c80b71a 100644
--- a/activemodel/test/cases/lint_test.rb
+++ b/activemodel/test/cases/lint_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "cases/helper"
 
 class LintTest < ActiveModel::TestCase
diff --git a/activemodel/test/cases/model_test.rb b/activemodel/test/cases/model_test.rb
index ba87cd1506..b24d7e3571 100644
--- a/activemodel/test/cases/model_test.rb
+++ b/activemodel/test/cases/model_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "cases/helper"
 
 class ModelTest < ActiveModel::TestCase
diff --git a/activemodel/test/cases/naming_test.rb b/activemodel/test/cases/naming_test.rb
index d5cb1a62bc..009f1f47af 100644
--- a/activemodel/test/cases/naming_test.rb
+++ b/activemodel/test/cases/naming_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "cases/helper"
 require "models/contact"
 require "models/sheep"
diff --git a/activemodel/test/cases/railtie_test.rb b/activemodel/test/cases/railtie_test.rb
index a56b26b5ee..ff5022e960 100644
--- a/activemodel/test/cases/railtie_test.rb
+++ b/activemodel/test/cases/railtie_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "cases/helper"
 require "active_support/testing/isolation"
 
diff --git a/activemodel/test/cases/secure_password_test.rb b/activemodel/test/cases/secure_password_test.rb
index 77ce86f392..d19e81a119 100644
--- a/activemodel/test/cases/secure_password_test.rb
+++ b/activemodel/test/cases/secure_password_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "cases/helper"
 require "models/user"
 require "models/visitor"
diff --git a/activemodel/test/cases/serialization_test.rb b/activemodel/test/cases/serialization_test.rb
index f78efd2f0c..9002982e7f 100644
--- a/activemodel/test/cases/serialization_test.rb
+++ b/activemodel/test/cases/serialization_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "cases/helper"
 require "active_support/core_ext/object/instance_variables"
 
diff --git a/activemodel/test/cases/serializers/json_serialization_test.rb b/activemodel/test/cases/serializers/json_serialization_test.rb
index d15ba64eb0..aae98c9fe4 100644
--- a/activemodel/test/cases/serializers/json_serialization_test.rb
+++ b/activemodel/test/cases/serializers/json_serialization_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "cases/helper"
 require "models/contact"
 require "active_support/core_ext/object/instance_variables"
diff --git a/activemodel/test/cases/translation_test.rb b/activemodel/test/cases/translation_test.rb
index 9972f9daea..cd75afec9e 100644
--- a/activemodel/test/cases/translation_test.rb
+++ b/activemodel/test/cases/translation_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "cases/helper"
 require "models/person"
 
diff --git a/activemodel/test/cases/type/big_integer_test.rb b/activemodel/test/cases/type/big_integer_test.rb
index 56002b7cc6..3d29235d52 100644
--- a/activemodel/test/cases/type/big_integer_test.rb
+++ b/activemodel/test/cases/type/big_integer_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "cases/helper"
 require "active_model/type"
 
diff --git a/activemodel/test/cases/type/binary_test.rb b/activemodel/test/cases/type/binary_test.rb
index e9c2ccfca4..ef4f125a3b 100644
--- a/activemodel/test/cases/type/binary_test.rb
+++ b/activemodel/test/cases/type/binary_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "cases/helper"
 require "active_model/type"
 
diff --git a/activemodel/test/cases/type/boolean_test.rb b/activemodel/test/cases/type/boolean_test.rb
index 92e5aebfb7..97b165ab48 100644
--- a/activemodel/test/cases/type/boolean_test.rb
+++ b/activemodel/test/cases/type/boolean_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "cases/helper"
 require "active_model/type"
 
diff --git a/activemodel/test/cases/type/date_test.rb b/activemodel/test/cases/type/date_test.rb
index 0cc90e99d3..15c40a37b7 100644
--- a/activemodel/test/cases/type/date_test.rb
+++ b/activemodel/test/cases/type/date_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "cases/helper"
 require "active_model/type"
 
diff --git a/activemodel/test/cases/type/date_time_test.rb b/activemodel/test/cases/type/date_time_test.rb
index 75a7fc686e..598ccf485e 100644
--- a/activemodel/test/cases/type/date_time_test.rb
+++ b/activemodel/test/cases/type/date_time_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "cases/helper"
 require "active_model/type"
 
diff --git a/activemodel/test/cases/type/decimal_test.rb b/activemodel/test/cases/type/decimal_test.rb
index c3b43725cc..a0acdc2736 100644
--- a/activemodel/test/cases/type/decimal_test.rb
+++ b/activemodel/test/cases/type/decimal_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "cases/helper"
 require "active_model/type"
 
diff --git a/activemodel/test/cases/type/float_test.rb b/activemodel/test/cases/type/float_test.rb
index 8026d63ad5..46e8b34dfe 100644
--- a/activemodel/test/cases/type/float_test.rb
+++ b/activemodel/test/cases/type/float_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "cases/helper"
 require "active_model/type"
 
diff --git a/activemodel/test/cases/type/immutable_string_test.rb b/activemodel/test/cases/type/immutable_string_test.rb
index 23e58974fb..72f5779dfb 100644
--- a/activemodel/test/cases/type/immutable_string_test.rb
+++ b/activemodel/test/cases/type/immutable_string_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "cases/helper"
 require "active_model/type"
 
diff --git a/activemodel/test/cases/type/integer_test.rb b/activemodel/test/cases/type/integer_test.rb
index a91144036b..d2e635b447 100644
--- a/activemodel/test/cases/type/integer_test.rb
+++ b/activemodel/test/cases/type/integer_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "cases/helper"
 require "active_model/type"
 require "active_support/core_ext/numeric/time"
diff --git a/activemodel/test/cases/type/registry_test.rb b/activemodel/test/cases/type/registry_test.rb
index 927b6d0307..f34104286c 100644
--- a/activemodel/test/cases/type/registry_test.rb
+++ b/activemodel/test/cases/type/registry_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "cases/helper"
 require "active_model/type"
 
diff --git a/activemodel/test/cases/type/string_test.rb b/activemodel/test/cases/type/string_test.rb
index 5bf9fc3527..d39389718b 100644
--- a/activemodel/test/cases/type/string_test.rb
+++ b/activemodel/test/cases/type/string_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "cases/helper"
 require "active_model/type"
 
diff --git a/activemodel/test/cases/type/time_test.rb b/activemodel/test/cases/type/time_test.rb
index 0cc4d33caa..0bea95768d 100644
--- a/activemodel/test/cases/type/time_test.rb
+++ b/activemodel/test/cases/type/time_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "cases/helper"
 require "active_model/type"
 
diff --git a/activemodel/test/cases/type/value_test.rb b/activemodel/test/cases/type/value_test.rb
index d8b3e7f164..671343b0c8 100644
--- a/activemodel/test/cases/type/value_test.rb
+++ b/activemodel/test/cases/type/value_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "cases/helper"
 require "active_model/type"
 
diff --git a/activemodel/test/cases/validations/absence_validation_test.rb b/activemodel/test/cases/validations/absence_validation_test.rb
index 833f694c5a..801577474a 100644
--- a/activemodel/test/cases/validations/absence_validation_test.rb
+++ b/activemodel/test/cases/validations/absence_validation_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "cases/helper"
 require "models/topic"
 require "models/person"
diff --git a/activemodel/test/cases/validations/acceptance_validation_test.rb b/activemodel/test/cases/validations/acceptance_validation_test.rb
index fbd994e914..c5f54b1868 100644
--- a/activemodel/test/cases/validations/acceptance_validation_test.rb
+++ b/activemodel/test/cases/validations/acceptance_validation_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "cases/helper"
 
 require "models/topic"
diff --git a/activemodel/test/cases/validations/callbacks_test.rb b/activemodel/test/cases/validations/callbacks_test.rb
index f2e4a5946d..d3a9a17a05 100644
--- a/activemodel/test/cases/validations/callbacks_test.rb
+++ b/activemodel/test/cases/validations/callbacks_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "cases/helper"
 
 class Dog
diff --git a/activemodel/test/cases/validations/conditional_validation_test.rb b/activemodel/test/cases/validations/conditional_validation_test.rb
index 048d27446e..68dade556c 100644
--- a/activemodel/test/cases/validations/conditional_validation_test.rb
+++ b/activemodel/test/cases/validations/conditional_validation_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "cases/helper"
 
 require "models/topic"
diff --git a/activemodel/test/cases/validations/confirmation_validation_test.rb b/activemodel/test/cases/validations/confirmation_validation_test.rb
index 7ddf3ad273..e84415a868 100644
--- a/activemodel/test/cases/validations/confirmation_validation_test.rb
+++ b/activemodel/test/cases/validations/confirmation_validation_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "cases/helper"
 
 require "models/topic"
diff --git a/activemodel/test/cases/validations/exclusion_validation_test.rb b/activemodel/test/cases/validations/exclusion_validation_test.rb
index 06ae4fbecd..68d611e904 100644
--- a/activemodel/test/cases/validations/exclusion_validation_test.rb
+++ b/activemodel/test/cases/validations/exclusion_validation_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "cases/helper"
 require "active_support/core_ext/numeric/time"
 
diff --git a/activemodel/test/cases/validations/format_validation_test.rb b/activemodel/test/cases/validations/format_validation_test.rb
index f5b1ad721c..3ddda2154a 100644
--- a/activemodel/test/cases/validations/format_validation_test.rb
+++ b/activemodel/test/cases/validations/format_validation_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "cases/helper"
 
 require "models/topic"
diff --git a/activemodel/test/cases/validations/i18n_generate_message_validation_test.rb b/activemodel/test/cases/validations/i18n_generate_message_validation_test.rb
index f049ee26e8..d3e44945db 100644
--- a/activemodel/test/cases/validations/i18n_generate_message_validation_test.rb
+++ b/activemodel/test/cases/validations/i18n_generate_message_validation_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "cases/helper"
 
 require "models/person"
diff --git a/activemodel/test/cases/validations/i18n_validation_test.rb b/activemodel/test/cases/validations/i18n_validation_test.rb
index f28cfc0ef5..9cfe189d0e 100644
--- a/activemodel/test/cases/validations/i18n_validation_test.rb
+++ b/activemodel/test/cases/validations/i18n_validation_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "cases/helper"
 require "models/person"
 
diff --git a/activemodel/test/cases/validations/inclusion_validation_test.rb b/activemodel/test/cases/validations/inclusion_validation_test.rb
index 5aa43ea4a9..94df0649a9 100644
--- a/activemodel/test/cases/validations/inclusion_validation_test.rb
+++ b/activemodel/test/cases/validations/inclusion_validation_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "cases/helper"
 require "active_support/all"
 
diff --git a/activemodel/test/cases/validations/length_validation_test.rb b/activemodel/test/cases/validations/length_validation_test.rb
index 95ee87b401..a0d8e058f5 100644
--- a/activemodel/test/cases/validations/length_validation_test.rb
+++ b/activemodel/test/cases/validations/length_validation_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "cases/helper"
 
 require "models/topic"
diff --git a/activemodel/test/cases/validations/numericality_validation_test.rb b/activemodel/test/cases/validations/numericality_validation_test.rb
index c0158e075f..001815e28f 100644
--- a/activemodel/test/cases/validations/numericality_validation_test.rb
+++ b/activemodel/test/cases/validations/numericality_validation_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "cases/helper"
 
 require "models/topic"
diff --git a/activemodel/test/cases/validations/presence_validation_test.rb b/activemodel/test/cases/validations/presence_validation_test.rb
index 642dd0f144..22c2f0af87 100644
--- a/activemodel/test/cases/validations/presence_validation_test.rb
+++ b/activemodel/test/cases/validations/presence_validation_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "cases/helper"
 
 require "models/topic"
diff --git a/activemodel/test/cases/validations/validates_test.rb b/activemodel/test/cases/validations/validates_test.rb
index 011033606e..77cb8ebdc1 100644
--- a/activemodel/test/cases/validations/validates_test.rb
+++ b/activemodel/test/cases/validations/validates_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "cases/helper"
 require "models/person"
 require "models/topic"
diff --git a/activemodel/test/cases/validations/validations_context_test.rb b/activemodel/test/cases/validations/validations_context_test.rb
index 25c37a572f..024eb1882f 100644
--- a/activemodel/test/cases/validations/validations_context_test.rb
+++ b/activemodel/test/cases/validations/validations_context_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "cases/helper"
 
 require "models/topic"
diff --git a/activemodel/test/cases/validations/with_validation_test.rb b/activemodel/test/cases/validations/with_validation_test.rb
index 5ce86738cd..fbe20dc000 100644
--- a/activemodel/test/cases/validations/with_validation_test.rb
+++ b/activemodel/test/cases/validations/with_validation_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "cases/helper"
 
 require "models/topic"
diff --git a/activemodel/test/cases/validations_test.rb b/activemodel/test/cases/validations_test.rb
index 6647191205..ab8c41bbd0 100644
--- a/activemodel/test/cases/validations_test.rb
+++ b/activemodel/test/cases/validations_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "cases/helper"
 
 require "models/topic"
diff --git a/activemodel/test/models/account.rb b/activemodel/test/models/account.rb
index eed668d38f..40408e5708 100644
--- a/activemodel/test/models/account.rb
+++ b/activemodel/test/models/account.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 class Account
   include ActiveModel::ForbiddenAttributesProtection
 
diff --git a/activemodel/test/models/blog_post.rb b/activemodel/test/models/blog_post.rb
index 46eba857df..d4b02eeaa7 100644
--- a/activemodel/test/models/blog_post.rb
+++ b/activemodel/test/models/blog_post.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Blog
   def self.use_relative_model_naming?
     true
diff --git a/activemodel/test/models/contact.rb b/activemodel/test/models/contact.rb
index 113ab0bc1f..c40a6d6f0e 100644
--- a/activemodel/test/models/contact.rb
+++ b/activemodel/test/models/contact.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 class Contact
   extend ActiveModel::Naming
   include ActiveModel::Conversion
diff --git a/activemodel/test/models/custom_reader.rb b/activemodel/test/models/custom_reader.rb
index dc26bb10ff..df605e93d9 100644
--- a/activemodel/test/models/custom_reader.rb
+++ b/activemodel/test/models/custom_reader.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 class CustomReader
   include ActiveModel::Validations
 
diff --git a/activemodel/test/models/helicopter.rb b/activemodel/test/models/helicopter.rb
index 933f3c463a..fe82c463d3 100644
--- a/activemodel/test/models/helicopter.rb
+++ b/activemodel/test/models/helicopter.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 class Helicopter
   include ActiveModel::Conversion
 end
diff --git a/activemodel/test/models/person.rb b/activemodel/test/models/person.rb
index e896e90f98..b61fdf76b1 100644
--- a/activemodel/test/models/person.rb
+++ b/activemodel/test/models/person.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 class Person
   include ActiveModel::Validations
   extend  ActiveModel::Translation
diff --git a/activemodel/test/models/person_with_validator.rb b/activemodel/test/models/person_with_validator.rb
index 505ed880c1..44e78cbc29 100644
--- a/activemodel/test/models/person_with_validator.rb
+++ b/activemodel/test/models/person_with_validator.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 class PersonWithValidator
   include ActiveModel::Validations
 
diff --git a/activemodel/test/models/reply.rb b/activemodel/test/models/reply.rb
index 3fe11043d2..6bb18f95fe 100644
--- a/activemodel/test/models/reply.rb
+++ b/activemodel/test/models/reply.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "models/topic"
 
 class Reply < Topic
diff --git a/activemodel/test/models/sheep.rb b/activemodel/test/models/sheep.rb
index 7aba055c4f..30dd9ce192 100644
--- a/activemodel/test/models/sheep.rb
+++ b/activemodel/test/models/sheep.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 class Sheep
   extend ActiveModel::Naming
 end
diff --git a/activemodel/test/models/topic.rb b/activemodel/test/models/topic.rb
index 192786c096..2f4e92c3b2 100644
--- a/activemodel/test/models/topic.rb
+++ b/activemodel/test/models/topic.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 class Topic
   include ActiveModel::Validations
   include ActiveModel::Validations::Callbacks
diff --git a/activemodel/test/models/track_back.rb b/activemodel/test/models/track_back.rb
index 357ee37d6d..728a022db5 100644
--- a/activemodel/test/models/track_back.rb
+++ b/activemodel/test/models/track_back.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 class Post
   class TrackBack
     def to_model
diff --git a/activemodel/test/models/user.rb b/activemodel/test/models/user.rb
index 6556b1a7d9..e98fd8a0a1 100644
--- a/activemodel/test/models/user.rb
+++ b/activemodel/test/models/user.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 class User
   extend ActiveModel::Callbacks
   include ActiveModel::SecurePassword
diff --git a/activemodel/test/models/visitor.rb b/activemodel/test/models/visitor.rb
index 22ad1a3c3d..9da004ffcc 100644
--- a/activemodel/test/models/visitor.rb
+++ b/activemodel/test/models/visitor.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 class Visitor
   extend ActiveModel::Callbacks
   include ActiveModel::SecurePassword
diff --git a/activemodel/test/validators/email_validator.rb b/activemodel/test/validators/email_validator.rb
index f733c45cf0..0c634d8659 100644
--- a/activemodel/test/validators/email_validator.rb
+++ b/activemodel/test/validators/email_validator.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 class EmailValidator < ActiveModel::EachValidator
   def validate_each(record, attribute, value)
     record.errors[attribute] << (options[:message] || "is not an email") unless
diff --git a/activemodel/test/validators/namespace/email_validator.rb b/activemodel/test/validators/namespace/email_validator.rb
index 8639045b0d..e7815d92dc 100644
--- a/activemodel/test/validators/namespace/email_validator.rb
+++ b/activemodel/test/validators/namespace/email_validator.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "validators/email_validator"
 
 module Namespace