Merge branch 'master' into update_default_hsts_max_age

37 files changed, 531 insertions, 566 deletions

diff --git a/activemodel/CHANGELOG.md b/activemodel/CHANGELOG.md
index b67a803b9d..b28c83e4ed 100644
--- a/activemodel/CHANGELOG.md
+++ b/activemodel/CHANGELOG.md
@@ -1,60 +1,8 @@
-*   Fix to working before/after validation callbacks on multiple contexts.
+## Rails 6.0.0.alpha (Unreleased) ##
 
-    *Yoshiyuki Hirano*
+*   Rails 6 requires Ruby 2.4.1 or newer.
 
-## Rails 5.2.0.beta2 (November 28, 2017) ##
+    *Jeremy Daer*
 
-*   No changes.
 
-
-## Rails 5.2.0.beta1 (November 27, 2017) ##
-
-*   Execute `ConfirmationValidator` validation when `_confirmation`'s value is `false`.
-
-    *bogdanvlviv*
-
-*   Allow passing a Proc or Symbol to length validator options.
-
-    *Matt Rohrer*
-
-*   Add method `#merge!` for `ActiveModel::Errors`.
-
-    *Jahfer Husain*
-
-*   Fix regression in numericality validator when comparing Decimal and Float input
-    values with more scale than the schema.
-
-    *Bradley Priest*
-
-*   Fix methods `#keys`, `#values` in `ActiveModel::Errors`.
-
-    Change `#keys` to only return the keys that don't have empty messages.
-
-    Change `#values` to only return the not empty values.
-
-    Example:
-
-        # Before
-        person = Person.new
-        person.errors.keys     # => []
-        person.errors.values   # => []
-        person.errors.messages # => {}
-        person.errors[:name]   # => []
-        person.errors.messages # => {:name => []}
-        person.errors.keys     # => [:name]
-        person.errors.values   # => [[]]
-
-        # After
-        person = Person.new
-        person.errors.keys     # => []
-        person.errors.values   # => []
-        person.errors.messages # => {}
-        person.errors[:name]   # => []
-        person.errors.messages # => {:name => []}
-        person.errors.keys     # => []
-        person.errors.values   # => []
-
-    *bogdanvlviv*
-
-
-Please check [5-1-stable](https://github.com/rails/rails/blob/5-1-stable/activemodel/CHANGELOG.md) for previous changes.
+Please check [5-2-stable](https://github.com/rails/rails/blob/5-2-stable/activemodel/CHANGELOG.md) for previous changes.
diff --git a/activemodel/activemodel.gemspec b/activemodel/activemodel.gemspec
index a070a2898c..7be466dc4c 100644
--- a/activemodel/activemodel.gemspec
+++ b/activemodel/activemodel.gemspec
@@ -9,7 +9,7 @@ Gem::Specification.new do |s|
   s.summary     = "A toolkit for building modeling frameworks (part of Rails)."
   s.description = "A toolkit for building modeling frameworks like Active Record. Rich support for attributes, callbacks, validations, serialization, internationalization, and testing."
 
-  s.required_ruby_version = ">= 2.2.2"
+  s.required_ruby_version = ">= 2.4.1"
 
   s.license = "MIT"
 
diff --git a/activemodel/lib/active_model/attribute/user_provided_default.rb b/activemodel/lib/active_model/attribute/user_provided_default.rb
index f274b687d4..a5dc6188d2 100644
--- a/activemodel/lib/active_model/attribute/user_provided_default.rb
+++ b/activemodel/lib/active_model/attribute/user_provided_default.rb
@@ -22,6 +22,28 @@ module ActiveModel
         self.class.new(name, user_provided_value, type, original_attribute)
       end
 
+      def marshal_dump
+        result = [
+          name,
+          value_before_type_cast,
+          type,
+          original_attribute,
+        ]
+        result << value if defined?(@value)
+        result
+      end
+
+      def marshal_load(values)
+        name, user_provided_value, type, original_attribute, value = values
+        @name = name
+        @user_provided_value = user_provided_value
+        @type = type
+        @original_attribute = original_attribute
+        if values.length == 5
+          @value = value
+        end
+      end
+
       protected
 
         attr_reader :user_provided_value
diff --git a/activemodel/lib/active_model/attribute_mutation_tracker.rb b/activemodel/lib/active_model/attribute_mutation_tracker.rb
index c67e1b809a..8e92c8807f 100644
--- a/activemodel/lib/active_model/attribute_mutation_tracker.rb
+++ b/activemodel/lib/active_model/attribute_mutation_tracker.rb
@@ -35,6 +35,10 @@ module ActiveModel
       end
     end
 
+    def changed_attribute_names
+      attr_names.select { |attr| changed?(attr) }
+    end
+
     def any_changes?
       attr_names.any? { |attr| changed?(attr) }
     end
@@ -65,13 +69,8 @@ module ActiveModel
       forced_changes << attr_name.to_s
     end
 
-    # TODO Change this to private once we've dropped Ruby 2.2 support.
-    # Workaround for Ruby 2.2 "private attribute?" warning.
-    protected
-
-      attr_reader :attributes, :forced_changes
-
     private
+      attr_reader :attributes, :forced_changes
 
       def attr_names
         attributes.keys
@@ -109,8 +108,5 @@ module ActiveModel
 
     def original_value(*)
     end
-
-    def force_change(*)
-    end
   end
 end
diff --git a/activemodel/lib/active_model/attribute_set/builder.rb b/activemodel/lib/active_model/attribute_set/builder.rb
index 758eb830fc..bf2d06b48a 100644
--- a/activemodel/lib/active_model/attribute_set/builder.rb
+++ b/activemodel/lib/active_model/attribute_set/builder.rb
@@ -22,12 +22,12 @@ module ActiveModel
   class LazyAttributeHash # :nodoc:
     delegate :transform_values, :each_key, :each_value, :fetch, :except, to: :materialize
 
-    def initialize(types, values, additional_types, default_attributes)
+    def initialize(types, values, additional_types, default_attributes, delegate_hash = {})
       @types = types
       @values = values
       @additional_types = additional_types
       @materialized = false
-      @delegate_hash = {}
+      @delegate_hash = delegate_hash
       @default_attributes = default_attributes
     end
 
@@ -76,15 +76,17 @@ module ActiveModel
     end
 
     def marshal_dump
-      materialize
+      [@types, @values, @additional_types, @default_attributes, @delegate_hash]
     end
 
-    def marshal_load(delegate_hash)
-      @delegate_hash = delegate_hash
-      @types = {}
-      @values = {}
-      @additional_types = {}
-      @materialized = true
+    def marshal_load(values)
+      if values.is_a?(Hash)
+        empty_hash = {}.freeze
+        initialize(empty_hash, empty_hash, empty_hash, empty_hash, values)
+        @materialized = true
+      else
+        initialize(*values)
+      end
     end
 
     protected
diff --git a/activemodel/lib/active_model/attributes.rb b/activemodel/lib/active_model/attributes.rb
index 28dd24b3cd..046ae67ad7 100644
--- a/activemodel/lib/active_model/attributes.rb
+++ b/activemodel/lib/active_model/attributes.rb
@@ -23,7 +23,7 @@ module ActiveModel
         end
         self.attribute_types = attribute_types.merge(name => type)
         define_default_attribute(name, options.fetch(:default, NO_DEFAULT_PROVIDED), type)
-        define_attribute_methods(name)
+        define_attribute_method(name)
       end
 
       private
diff --git a/activemodel/lib/active_model/dirty.rb b/activemodel/lib/active_model/dirty.rb
index d2ebd18107..0044fde6c5 100644
--- a/activemodel/lib/active_model/dirty.rb
+++ b/activemodel/lib/active_model/dirty.rb
@@ -3,6 +3,7 @@
 require "active_support/hash_with_indifferent_access"
 require "active_support/core_ext/object/duplicable"
 require "active_model/attribute_mutation_tracker"
+require "active_model/attribute_set"
 
 module ActiveModel
   # == Active \Model \Dirty
@@ -142,9 +143,8 @@ module ActiveModel
     end
 
     def changes_applied # :nodoc:
-      @previously_changed = changes
+      _prepare_changes
       @mutations_before_last_save = mutations_from_database
-      @attributes_changed_by_setter = ActiveSupport::HashWithIndifferentAccess.new
       forget_attribute_assignments
       @mutations_from_database = nil
     end
@@ -155,7 +155,7 @@ module ActiveModel
     #   person.name = 'bob'
     #   person.changed? # => true
     def changed?
-      changed_attributes.present?
+      mutations_from_database.any_changes?
     end
 
     # Returns an array with the name of the attributes with unsaved changes.
@@ -164,24 +164,24 @@ module ActiveModel
     #   person.name = 'bob'
     #   person.changed # => ["name"]
     def changed
-      changed_attributes.keys
+      mutations_from_database.changed_attribute_names
     end
 
     # Handles <tt>*_changed?</tt> for +method_missing+.
     def attribute_changed?(attr, from: OPTION_NOT_GIVEN, to: OPTION_NOT_GIVEN) # :nodoc:
-      !!changes_include?(attr) &&
+      !!mutations_from_database.changed?(attr) &&
         (to == OPTION_NOT_GIVEN || to == _read_attribute(attr)) &&
-        (from == OPTION_NOT_GIVEN || from == changed_attributes[attr])
+        (from == OPTION_NOT_GIVEN || from == attribute_was(attr))
     end
 
     # Handles <tt>*_was</tt> for +method_missing+.
     def attribute_was(attr) # :nodoc:
-      attribute_changed?(attr) ? changed_attributes[attr] : _read_attribute(attr)
+      mutations_from_database.original_value(attr)
     end
 
     # Handles <tt>*_previously_changed?</tt> for +method_missing+.
     def attribute_previously_changed?(attr) #:nodoc:
-      previous_changes_include?(attr)
+      mutations_before_last_save.changed?(attr)
     end
 
     # Restore all previous data of the provided attributes.
@@ -191,15 +191,12 @@ module ActiveModel
 
     # Clears all dirty data: current changes and previous changes.
     def clear_changes_information
-      @previously_changed = ActiveSupport::HashWithIndifferentAccess.new
       @mutations_before_last_save = nil
-      @attributes_changed_by_setter = ActiveSupport::HashWithIndifferentAccess.new
       forget_attribute_assignments
       @mutations_from_database = nil
     end
 
     def clear_attribute_changes(attr_names)
-      attributes_changed_by_setter.except!(*attr_names)
       attr_names.each do |attr_name|
         clear_attribute_change(attr_name)
       end
@@ -212,13 +209,7 @@ module ActiveModel
     #   person.name = 'robert'
     #   person.changed_attributes # => {"name" => "bob"}
     def changed_attributes
-      # This should only be set by methods which will call changed_attributes
-      # multiple times when it is known that the computed value cannot change.
-      if defined?(@cached_changed_attributes)
-        @cached_changed_attributes
-      else
-        attributes_changed_by_setter.reverse_merge(mutations_from_database.changed_values).freeze
-      end
+      mutations_from_database.changed_values.freeze
     end
 
     # Returns a hash of changed attributes indicating their original
@@ -228,9 +219,8 @@ module ActiveModel
     #   person.name = 'bob'
     #   person.changes # => { "name" => ["bill", "bob"] }
     def changes
-      cache_changed_attributes do
-        ActiveSupport::HashWithIndifferentAccess[changed.map { |attr| [attr, attribute_change(attr)] }]
-      end
+      _prepare_changes
+      mutations_from_database.changes
     end
 
     # Returns a hash of attributes that were changed before the model was saved.
@@ -240,8 +230,7 @@ module ActiveModel
     #   person.save
     #   person.previous_changes # => {"name" => ["bob", "robert"]}
     def previous_changes
-      @previously_changed ||= ActiveSupport::HashWithIndifferentAccess.new
-      @previously_changed.merge(mutations_before_last_save.changes)
+      mutations_before_last_save.changes
     end
 
     def attribute_changed_in_place?(attr_name) # :nodoc:
@@ -257,11 +246,17 @@ module ActiveModel
         unless defined?(@mutations_from_database)
           @mutations_from_database = nil
         end
-        @mutations_from_database ||= if defined?(@attributes)
-          ActiveModel::AttributeMutationTracker.new(@attributes)
-        else
-          NullMutationTracker.instance
+
+        unless defined?(@attributes)
+          @_pseudo_attributes = true
+          @attributes = AttributeSet.new(
+            Hash.new { |h, attr|
+              h[attr] = Attribute.with_cast_value(attr, _clone_attribute(attr), Type.default_value)
+            }
+          )
         end
+
+        @mutations_from_database ||= ActiveModel::AttributeMutationTracker.new(@attributes)
       end
 
       def forget_attribute_assignments
@@ -272,68 +267,45 @@ module ActiveModel
         @mutations_before_last_save ||= ActiveModel::NullMutationTracker.instance
       end
 
-      def cache_changed_attributes
-        @cached_changed_attributes = changed_attributes
-        yield
-      ensure
-        clear_changed_attributes_cache
-      end
-
-      def clear_changed_attributes_cache
-        remove_instance_variable(:@cached_changed_attributes) if defined?(@cached_changed_attributes)
-      end
-
-      # Returns +true+ if attr_name is changed, +false+ otherwise.
-      def changes_include?(attr_name)
-        attributes_changed_by_setter.include?(attr_name) || mutations_from_database.changed?(attr_name)
-      end
-      alias attribute_changed_by_setter? changes_include?
-
-      # Returns +true+ if attr_name were changed before the model was saved,
-      # +false+ otherwise.
-      def previous_changes_include?(attr_name)
-        previous_changes.include?(attr_name)
-      end
-
       # Handles <tt>*_change</tt> for +method_missing+.
       def attribute_change(attr)
-        [changed_attributes[attr], _read_attribute(attr)] if attribute_changed?(attr)
+        [attribute_was(attr), _read_attribute(attr)] if attribute_changed?(attr)
       end
 
       # Handles <tt>*_previous_change</tt> for +method_missing+.
       def attribute_previous_change(attr)
-        previous_changes[attr] if attribute_previously_changed?(attr)
+        mutations_before_last_save.change_to_attribute(attr)
       end
 
       # Handles <tt>*_will_change!</tt> for +method_missing+.
       def attribute_will_change!(attr)
-        unless attribute_changed?(attr)
-          begin
-            value = _read_attribute(attr)
-            value = value.duplicable? ? value.clone : value
-          rescue TypeError, NoMethodError
-          end
-
-          set_attribute_was(attr, value)
+        attr = attr.to_s
+        mutations_from_database.force_change(attr).tap do
+          @attributes[attr] if defined?(@_pseudo_attributes)
         end
-        mutations_from_database.force_change(attr)
       end
 
       # Handles <tt>restore_*!</tt> for +method_missing+.
       def restore_attribute!(attr)
         if attribute_changed?(attr)
-          __send__("#{attr}=", changed_attributes[attr])
+          __send__("#{attr}=", attribute_was(attr))
           clear_attribute_changes([attr])
         end
       end
 
-      def attributes_changed_by_setter
-        @attributes_changed_by_setter ||= ActiveSupport::HashWithIndifferentAccess.new
+      def _prepare_changes
+        if defined?(@_pseudo_attributes)
+          changed.each do |attr|
+            @attributes.write_from_user(attr, _read_attribute(attr))
+          end
+        end
       end
 
-      # Force an attribute to have a particular "before" value
-      def set_attribute_was(attr, old_value)
-        attributes_changed_by_setter[attr] = old_value
+      def _clone_attribute(attr)
+        value = _read_attribute(attr)
+        value.duplicable? ? value.clone : value
+      rescue TypeError, NoMethodError
+        value
       end
   end
 end
diff --git a/activemodel/lib/active_model/gem_version.rb b/activemodel/lib/active_model/gem_version.rb
index 3c344fe854..cef5441e4a 100644
--- a/activemodel/lib/active_model/gem_version.rb
+++ b/activemodel/lib/active_model/gem_version.rb
@@ -7,10 +7,10 @@ module ActiveModel
   end
 
   module VERSION
-    MAJOR = 5
-    MINOR = 2
+    MAJOR = 6
+    MINOR = 0
     TINY  = 0
-    PRE   = "beta2"
+    PRE   = "alpha"
 
     STRING = [MAJOR, MINOR, TINY, PRE].compact.join(".")
   end
diff --git a/activemodel/lib/active_model/lint.rb b/activemodel/lib/active_model/lint.rb
index 34d9ac6c96..b7ceabb59a 100644
--- a/activemodel/lib/active_model/lint.rb
+++ b/activemodel/lib/active_model/lint.rb
@@ -29,7 +29,7 @@ module ActiveModel
       # <tt>to_key</tt> returns an Enumerable of all (primary) key attributes
       # of the model, and is used to a generate unique DOM id for the object.
       def test_to_key
-        assert model.respond_to?(:to_key), "The model should respond to to_key"
+        assert_respond_to model, :to_key
         def model.persisted?() false end
         assert model.to_key.nil?, "to_key should return nil when `persisted?` returns false"
       end
@@ -44,7 +44,7 @@ module ActiveModel
       # tests for this behavior in lint because it doesn't make sense to force
       # any of the possible implementation strategies on the implementer.
       def test_to_param
-        assert model.respond_to?(:to_param), "The model should respond to to_param"
+        assert_respond_to model, :to_param
         def model.to_key() [1] end
         def model.persisted?() false end
         assert model.to_param.nil?, "to_param should return nil when `persisted?` returns false"
@@ -56,7 +56,7 @@ module ActiveModel
       # <tt>to_partial_path</tt> is used for looking up partials. For example,
       # a BlogPost model might return "blog_posts/blog_post".
       def test_to_partial_path
-        assert model.respond_to?(:to_partial_path), "The model should respond to to_partial_path"
+        assert_respond_to model, :to_partial_path
         assert_kind_of String, model.to_partial_path
       end
 
@@ -68,7 +68,7 @@ module ActiveModel
       # will route to the create action. If it is persisted, a form for the
       # object will route to the update action.
       def test_persisted?
-        assert model.respond_to?(:persisted?), "The model should respond to persisted?"
+        assert_respond_to model, :persisted?
         assert_boolean model.persisted?, "persisted?"
       end
 
@@ -79,14 +79,14 @@ module ActiveModel
       #
       # Check ActiveModel::Naming for more information.
       def test_model_naming
-        assert model.class.respond_to?(:model_name), "The model class should respond to model_name"
+        assert_respond_to model.class, :model_name
         model_name = model.class.model_name
-        assert model_name.respond_to?(:to_str)
-        assert model_name.human.respond_to?(:to_str)
-        assert model_name.singular.respond_to?(:to_str)
-        assert model_name.plural.respond_to?(:to_str)
+        assert_respond_to model_name, :to_str
+        assert_respond_to model_name.human, :to_str
+        assert_respond_to model_name.singular, :to_str
+        assert_respond_to model_name.plural, :to_str
 
-        assert model.respond_to?(:model_name), "The model instance should respond to model_name"
+        assert_respond_to model, :model_name
         assert_equal model.model_name, model.class.model_name
       end
 
@@ -100,13 +100,13 @@ module ActiveModel
       # If localization is used, the strings should be localized for the current
       # locale. If no error is present, the method should return an empty array.
       def test_errors_aref
-        assert model.respond_to?(:errors), "The model should respond to errors"
+        assert_respond_to model, :errors
         assert model.errors[:hello].is_a?(Array), "errors#[] should return an Array"
       end
 
       private
         def model
-          assert @model.respond_to?(:to_model), "The object should respond to to_model"
+          assert_respond_to @model, :to_model
           @model.to_model
         end
 
diff --git a/activemodel/lib/active_model/type/date.rb b/activemodel/lib/active_model/type/date.rb
index 8cecc16d0f..8ec5deedc4 100644
--- a/activemodel/lib/active_model/type/date.rb
+++ b/activemodel/lib/active_model/type/date.rb
@@ -42,7 +42,7 @@ module ActiveModel
         end
 
         def new_date(year, mon, mday)
-          if year && year != 0
+          unless year.nil? || (year == 0 && mon == 0 && mday == 0)
             ::Date.new(year, mon, mday) rescue nil
           end
         end
diff --git a/activemodel/lib/active_model/type/integer.rb b/activemodel/lib/active_model/type/integer.rb
index fe396998a3..da74aaa3c5 100644
--- a/activemodel/lib/active_model/type/integer.rb
+++ b/activemodel/lib/active_model/type/integer.rb
@@ -31,13 +31,8 @@ module ActiveModel
         result
       end
 
-      # TODO Change this to private once we've dropped Ruby 2.2 support.
-      # Workaround for Ruby 2.2 "private attribute?" warning.
-      protected
-
-        attr_reader :range
-
       private
+        attr_reader :range
 
         def cast_value(value)
           case value
diff --git a/activemodel/lib/active_model/type/registry.rb b/activemodel/lib/active_model/type/registry.rb
index 7272d7b0c5..a19dc0f011 100644
--- a/activemodel/lib/active_model/type/registry.rb
+++ b/activemodel/lib/active_model/type/registry.rb
@@ -23,13 +23,8 @@ module ActiveModel
         end
       end
 
-      # TODO Change this to private once we've dropped Ruby 2.2 support.
-      # Workaround for Ruby 2.2 "private attribute?" warning.
-      protected
-
-        attr_reader :registrations
-
       private
+        attr_reader :registrations
 
         def registration_klass
           Registration
@@ -59,10 +54,7 @@ module ActiveModel
         type_name == name
       end
 
-      # TODO Change this to private once we've dropped Ruby 2.2 support.
-      # Workaround for Ruby 2.2 "private attribute?" warning.
-      protected
-
+      private
         attr_reader :name, :block
     end
   end
diff --git a/activemodel/lib/active_model/validations/acceptance.rb b/activemodel/lib/active_model/validations/acceptance.rb
index f35e4dec7f..ea3a6b52ab 100644
--- a/activemodel/lib/active_model/validations/acceptance.rb
+++ b/activemodel/lib/active_model/validations/acceptance.rb
@@ -58,13 +58,8 @@ module ActiveModel
             klass.send(:attr_writer, *attr_writers)
           end
 
-          # TODO Change this to private once we've dropped Ruby 2.2 support.
-          # Workaround for Ruby 2.2 "private attribute?" warning.
-          protected
-
-            attr_reader :attributes
-
           private
+            attr_reader :attributes
 
             def convert_to_reader_name(method_name)
               method_name.to_s.chomp("=")
diff --git a/activemodel/lib/active_model/validations/clusivity.rb b/activemodel/lib/active_model/validations/clusivity.rb
index 0b9b5ce6a1..bafb8e2106 100644
--- a/activemodel/lib/active_model/validations/clusivity.rb
+++ b/activemodel/lib/active_model/validations/clusivity.rb
@@ -32,7 +32,7 @@ module ActiveModel
         @delimiter ||= options[:in] || options[:within]
       end
 
-      # In Ruby 2.2 <tt>Range#include?</tt> on non-number-or-time-ish ranges checks all
+      # After Ruby 2.2, <tt>Range#include?</tt> on non-number-or-time-ish ranges checks all
       # possible values in the range for equality, which is slower but more accurate.
       # <tt>Range#cover?</tt> uses the previous logic of comparing a value with the range
       # endpoints, which is fast but is only accurate on Numeric, Time, Date,
diff --git a/activemodel/test/cases/attribute_assignment_test.rb b/activemodel/test/cases/attribute_assignment_test.rb
index 5ecf0a69c4..448f8587fd 100644
--- a/activemodel/test/cases/attribute_assignment_test.rb
+++ b/activemodel/test/cases/attribute_assignment_test.rb
@@ -18,10 +18,7 @@ class AttributeAssignmentTest < ActiveModel::TestCase
       raise ErrorFromAttributeWriter
     end
 
-    # TODO Change this to private once we've dropped Ruby 2.2 support.
-    # Workaround for Ruby 2.2 "private attribute?" warning.
-    protected
-
+    private
       attr_writer :metadata
   end
 
diff --git a/activemodel/test/cases/attribute_methods_test.rb b/activemodel/test/cases/attribute_methods_test.rb
index d2837ec894..0cfc6f4b6b 100644
--- a/activemodel/test/cases/attribute_methods_test.rb
+++ b/activemodel/test/cases/attribute_methods_test.rb
@@ -220,7 +220,7 @@ class AttributeMethodsTest < ActiveModel::TestCase
     ModelWithAttributes.define_attribute_methods(:foo)
     ModelWithAttributes.undefine_attribute_methods
 
-    assert !ModelWithAttributes.new.respond_to?(:foo)
+    assert_not_respond_to ModelWithAttributes.new, :foo
     assert_raises(NoMethodError) { ModelWithAttributes.new.foo }
   end
 
@@ -255,7 +255,7 @@ class AttributeMethodsTest < ActiveModel::TestCase
     m = ModelWithAttributes2.new
     m.attributes = { "private_method" => "<3", "protected_method" => "O_o" }
 
-    assert !m.respond_to?(:private_method)
+    assert_not_respond_to m, :private_method
     assert m.respond_to?(:private_method, true)
 
     c = ClassWithProtected.new
diff --git a/activemodel/test/cases/attribute_set_test.rb b/activemodel/test/cases/attribute_set_test.rb
index 6e522d6c80..b868dba743 100644
--- a/activemodel/test/cases/attribute_set_test.rb
+++ b/activemodel/test/cases/attribute_set_test.rb
@@ -74,8 +74,8 @@ module ActiveModel
 
       clone.freeze
 
-      assert clone.frozen?
-      assert_not attributes.frozen?
+      assert_predicate clone, :frozen?
+      assert_not_predicate attributes, :frozen?
     end
 
     test "to_hash returns a hash of the type cast values" do
@@ -105,8 +105,8 @@ module ActiveModel
 
     test "known columns are built with uninitialized attributes" do
       attributes = attributes_with_uninitialized_key
-      assert attributes[:foo].initialized?
-      assert_not attributes[:bar].initialized?
+      assert_predicate attributes[:foo], :initialized?
+      assert_not_predicate attributes[:bar], :initialized?
     end
 
     test "uninitialized attributes are not included in the attributes hash" do
@@ -169,7 +169,7 @@ module ActiveModel
 
       assert attributes.key?(:foo)
       assert_equal [:foo], attributes.keys
-      assert attributes[:foo].initialized?
+      assert_predicate attributes[:foo], :initialized?
     end
 
     class MyType
@@ -209,11 +209,6 @@ module ActiveModel
       assert_equal "value from user", attributes.fetch_value(:foo)
     end
 
-    def attributes_with_uninitialized_key
-      builder = AttributeSet::Builder.new(foo: Type::Integer.new, bar: Type::Float.new)
-      builder.build_from_database(foo: "1.1")
-    end
-
     test "freezing doesn't prevent the set from materializing" do
       builder = AttributeSet::Builder.new(foo: Type::String.new)
       attributes = builder.build_from_database(foo: "1")
@@ -222,6 +217,22 @@ module ActiveModel
       assert_equal({ foo: "1" }, attributes.to_hash)
     end
 
+    test "marshaling dump/load legacy materialized attribute hash" do
+      builder = AttributeSet::Builder.new(foo: Type::String.new)
+      attributes = builder.build_from_database(foo: "1")
+
+      attributes.instance_variable_get(:@attributes).instance_eval do
+        class << self
+          def marshal_dump
+            materialize
+          end
+        end
+      end
+
+      attributes = Marshal.load(Marshal.dump(attributes))
+      assert_equal({ foo: "1" }, attributes.to_hash)
+    end
+
     test "#accessed_attributes returns only attributes which have been read" do
       builder = AttributeSet::Builder.new(foo: Type::Value.new, bar: Type::Value.new)
       attributes = builder.build_from_database(foo: "1", bar: "2")
@@ -253,5 +264,11 @@ module ActiveModel
       assert_equal attributes, attributes2
       assert_not_equal attributes2, attributes3
     end
+
+    private
+      def attributes_with_uninitialized_key
+        builder = AttributeSet::Builder.new(foo: Type::Integer.new, bar: Type::Float.new)
+        builder.build_from_database(foo: "1.1")
+      end
   end
 end
diff --git a/activemodel/test/cases/attribute_test.rb b/activemodel/test/cases/attribute_test.rb
index 14d86cef97..ea2b0efd11 100644
--- a/activemodel/test/cases/attribute_test.rb
+++ b/activemodel/test/cases/attribute_test.rb
@@ -175,33 +175,33 @@ module ActiveModel
 
     test "an attribute has not been read by default" do
       attribute = Attribute.from_database(:foo, 1, Type::Value.new)
-      assert_not attribute.has_been_read?
+      assert_not_predicate attribute, :has_been_read?
     end
 
     test "an attribute has been read when its value is calculated" do
       attribute = Attribute.from_database(:foo, 1, Type::Value.new)
       attribute.value
-      assert attribute.has_been_read?
+      assert_predicate attribute, :has_been_read?
     end
 
     test "an attribute is not changed if it hasn't been assigned or mutated" do
       attribute = Attribute.from_database(:foo, 1, Type::Value.new)
 
-      refute attribute.changed?
+      assert_not_predicate attribute, :changed?
     end
 
     test "an attribute is changed if it's been assigned a new value" do
       attribute = Attribute.from_database(:foo, 1, Type::Value.new)
       changed = attribute.with_value_from_user(2)
 
-      assert changed.changed?
+      assert_predicate changed, :changed?
     end
 
     test "an attribute is not changed if it's assigned the same value" do
       attribute = Attribute.from_database(:foo, 1, Type::Value.new)
       unchanged = attribute.with_value_from_user(1)
 
-      refute unchanged.changed?
+      assert_not_predicate unchanged, :changed?
     end
 
     test "an attribute can not be mutated if it has not been read,
@@ -209,15 +209,15 @@ module ActiveModel
       type_which_raises_from_all_methods = Object.new
       attribute = Attribute.from_database(:foo, "bar", type_which_raises_from_all_methods)
 
-      assert_not attribute.changed_in_place?
+      assert_not_predicate attribute, :changed_in_place?
     end
 
     test "an attribute is changed if it has been mutated" do
       attribute = Attribute.from_database(:foo, "bar", Type::String.new)
       attribute.value << "!"
 
-      assert attribute.changed_in_place?
-      assert attribute.changed?
+      assert_predicate attribute, :changed_in_place?
+      assert_predicate attribute, :changed?
     end
 
     test "an attribute can forget its changes" do
@@ -226,7 +226,7 @@ module ActiveModel
       forgotten = changed.forgetting_assignment
 
       assert changed.changed? # sanity check
-      refute forgotten.changed?
+      assert_not_predicate forgotten, :changed?
     end
 
     test "with_value_from_user validates the value" do
diff --git a/activemodel/test/cases/attributes_dirty_test.rb b/activemodel/test/cases/attributes_dirty_test.rb
index 83a86371e0..c991176389 100644
--- a/activemodel/test/cases/attributes_dirty_test.rb
+++ b/activemodel/test/cases/attributes_dirty_test.rb
@@ -25,11 +25,11 @@ class AttributesDirtyTest < ActiveModel::TestCase
   end
 
   test "setting attribute will result in change" do
-    assert !@model.changed?
-    assert !@model.name_changed?
+    assert_not_predicate @model, :changed?
+    assert_not_predicate @model, :name_changed?
     @model.name = "Ringo"
-    assert @model.changed?
-    assert @model.name_changed?
+    assert_predicate @model, :changed?
+    assert_predicate @model, :name_changed?
   end
 
   test "list of changed attribute keys" do
@@ -71,35 +71,35 @@ class AttributesDirtyTest < ActiveModel::TestCase
   test "attribute mutation" do
     @model.name = "Yam"
     @model.save
-    assert !@model.name_changed?
+    assert_not_predicate @model, :name_changed?
     @model.name.replace("Hadad")
-    assert @model.name_changed?
+    assert_predicate @model, :name_changed?
   end
 
   test "resetting attribute" do
     @model.name = "Bob"
     @model.restore_name!
     assert_nil @model.name
-    assert !@model.name_changed?
+    assert_not_predicate @model, :name_changed?
   end
 
   test "setting color to same value should not result in change being recorded" do
     @model.color = "red"
-    assert @model.color_changed?
+    assert_predicate @model, :color_changed?
     @model.save
-    assert !@model.color_changed?
-    assert !@model.changed?
+    assert_not_predicate @model, :color_changed?
+    assert_not_predicate @model, :changed?
     @model.color = "red"
-    assert !@model.color_changed?
-    assert !@model.changed?
+    assert_not_predicate @model, :color_changed?
+    assert_not_predicate @model, :changed?
   end
 
   test "saving should reset model's changed status" do
     @model.name = "Alf"
-    assert @model.changed?
+    assert_predicate @model, :changed?
     @model.save
-    assert !@model.changed?
-    assert !@model.name_changed?
+    assert_not_predicate @model, :changed?
+    assert_not_predicate @model, :name_changed?
   end
 
   test "saving should preserve previous changes" do
@@ -118,7 +118,7 @@ class AttributesDirtyTest < ActiveModel::TestCase
   test "saving should preserve model's previous changed status" do
     @model.name = "Jericho Cane"
     @model.save
-    assert @model.name_previously_changed?
+    assert_predicate @model, :name_previously_changed?
   end
 
   test "previous value is preserved when changed after save" do
@@ -143,7 +143,7 @@ class AttributesDirtyTest < ActiveModel::TestCase
 
   test "using attribute_will_change! with a symbol" do
     @model.size = 1
-    assert @model.size_changed?
+    assert_predicate @model, :size_changed?
   end
 
   test "reload should reset all changes" do
@@ -170,7 +170,7 @@ class AttributesDirtyTest < ActiveModel::TestCase
 
     @model.restore_attributes
 
-    assert_not @model.changed?
+    assert_not_predicate @model, :changed?
     assert_equal "Dmitry", @model.name
     assert_equal "Red", @model.color
   end
@@ -184,7 +184,7 @@ class AttributesDirtyTest < ActiveModel::TestCase
 
     @model.restore_attributes(["name"])
 
-    assert @model.changed?
+    assert_predicate @model, :changed?
     assert_equal "Dmitry", @model.name
     assert_equal "White", @model.color
   end
diff --git a/activemodel/test/cases/attributes_test.rb b/activemodel/test/cases/attributes_test.rb
index e43bf15335..7c1d813ce0 100644
--- a/activemodel/test/cases/attributes_test.rb
+++ b/activemodel/test/cases/attributes_test.rb
@@ -64,5 +64,14 @@ module ActiveModel
 
       assert_equal "4.4", data.integer_field
     end
+
+    test "attributes with proc defaults can be marshalled" do
+      data = ModelForAttributesTest.new
+      attributes = data.instance_variable_get(:@attributes)
+      round_tripped = Marshal.load(Marshal.dump(data))
+      new_attributes = round_tripped.instance_variable_get(:@attributes)
+
+      assert_equal attributes, new_attributes
+    end
   end
 end
diff --git a/activemodel/test/cases/callbacks_test.rb b/activemodel/test/cases/callbacks_test.rb
index a5d29d0f22..1ec12d8222 100644
--- a/activemodel/test/cases/callbacks_test.rb
+++ b/activemodel/test/cases/callbacks_test.rb
@@ -85,21 +85,21 @@ class CallbacksTest < ActiveModel::TestCase
   end
 
   test "only selects which types of callbacks should be created" do
-    assert !ModelCallbacks.respond_to?(:before_initialize)
-    assert !ModelCallbacks.respond_to?(:around_initialize)
+    assert_not_respond_to ModelCallbacks, :before_initialize
+    assert_not_respond_to ModelCallbacks, :around_initialize
     assert_respond_to ModelCallbacks, :after_initialize
   end
 
   test "only selects which types of callbacks should be created from an array list" do
     assert_respond_to ModelCallbacks, :before_multiple
     assert_respond_to ModelCallbacks, :around_multiple
-    assert !ModelCallbacks.respond_to?(:after_multiple)
+    assert_not_respond_to ModelCallbacks, :after_multiple
   end
 
   test "no callbacks should be created" do
-    assert !ModelCallbacks.respond_to?(:before_empty)
-    assert !ModelCallbacks.respond_to?(:around_empty)
-    assert !ModelCallbacks.respond_to?(:after_empty)
+    assert_not_respond_to ModelCallbacks, :before_empty
+    assert_not_respond_to ModelCallbacks, :around_empty
+    assert_not_respond_to ModelCallbacks, :after_empty
   end
 
   class Violin
diff --git a/activemodel/test/cases/dirty_test.rb b/activemodel/test/cases/dirty_test.rb
index dfe041ff50..f769eb0da1 100644
--- a/activemodel/test/cases/dirty_test.rb
+++ b/activemodel/test/cases/dirty_test.rb
@@ -5,12 +5,13 @@ require "cases/helper"
 class DirtyTest < ActiveModel::TestCase
   class DirtyModel
     include ActiveModel::Dirty
-    define_attribute_methods :name, :color, :size
+    define_attribute_methods :name, :color, :size, :status
 
     def initialize
       @name = nil
       @color = nil
       @size = nil
+      @status = "initialized"
     end
 
     def name
@@ -40,6 +41,15 @@ class DirtyTest < ActiveModel::TestCase
       @size = val
     end
 
+    def status
+      @status
+    end
+
+    def status=(val)
+      status_will_change! unless val == @status
+      @status = val
+    end
+
     def save
       changes_applied
     end
@@ -54,11 +64,11 @@ class DirtyTest < ActiveModel::TestCase
   end
 
   test "setting attribute will result in change" do
-    assert !@model.changed?
-    assert !@model.name_changed?
+    assert_not_predicate @model, :changed?
+    assert_not_predicate @model, :name_changed?
     @model.name = "Ringo"
-    assert @model.changed?
-    assert @model.name_changed?
+    assert_predicate @model, :changed?
+    assert_predicate @model, :name_changed?
   end
 
   test "list of changed attribute keys" do
@@ -99,82 +109,93 @@ class DirtyTest < ActiveModel::TestCase
 
   test "attribute mutation" do
     @model.instance_variable_set("@name", "Yam".dup)
-    assert !@model.name_changed?
+    assert_not_predicate @model, :name_changed?
     @model.name.replace("Hadad")
-    assert !@model.name_changed?
+    assert_not_predicate @model, :name_changed?
     @model.name_will_change!
     @model.name.replace("Baal")
-    assert @model.name_changed?
+    assert_predicate @model, :name_changed?
   end
 
   test "resetting attribute" do
     @model.name = "Bob"
     @model.restore_name!
     assert_nil @model.name
-    assert !@model.name_changed?
+    assert_not_predicate @model, :name_changed?
   end
 
   test "setting color to same value should not result in change being recorded" do
     @model.color = "red"
-    assert @model.color_changed?
+    assert_predicate @model, :color_changed?
     @model.save
-    assert !@model.color_changed?
-    assert !@model.changed?
+    assert_not_predicate @model, :color_changed?
+    assert_not_predicate @model, :changed?
     @model.color = "red"
-    assert !@model.color_changed?
-    assert !@model.changed?
+    assert_not_predicate @model, :color_changed?
+    assert_not_predicate @model, :changed?
   end
 
   test "saving should reset model's changed status" do
     @model.name = "Alf"
-    assert @model.changed?
+    assert_predicate @model, :changed?
     @model.save
-    assert !@model.changed?
-    assert !@model.name_changed?
+    assert_not_predicate @model, :changed?
+    assert_not_predicate @model, :name_changed?
   end
 
   test "saving should preserve previous changes" do
     @model.name = "Jericho Cane"
+    @model.status = "waiting"
     @model.save
     assert_equal [nil, "Jericho Cane"], @model.previous_changes["name"]
+    assert_equal ["initialized", "waiting"], @model.previous_changes["status"]
   end
 
   test "setting new attributes should not affect previous changes" do
     @model.name = "Jericho Cane"
+    @model.status = "waiting"
     @model.save
     @model.name = "DudeFella ManGuy"
+    @model.status = "finished"
     assert_equal [nil, "Jericho Cane"], @model.name_previous_change
+    assert_equal ["initialized", "waiting"], @model.previous_changes["status"]
   end
 
   test "saving should preserve model's previous changed status" do
     @model.name = "Jericho Cane"
     @model.save
-    assert @model.name_previously_changed?
+    assert_predicate @model, :name_previously_changed?
   end
 
   test "previous value is preserved when changed after save" do
     assert_equal({}, @model.changed_attributes)
     @model.name = "Paul"
-    assert_equal({ "name" => nil }, @model.changed_attributes)
+    @model.status = "waiting"
+    assert_equal({ "name" => nil, "status" => "initialized" }, @model.changed_attributes)
 
     @model.save
 
     @model.name = "John"
-    assert_equal({ "name" => "Paul" }, @model.changed_attributes)
+    @model.status = "finished"
+    assert_equal({ "name" => "Paul", "status" => "waiting" }, @model.changed_attributes)
   end
 
   test "changing the same attribute multiple times retains the correct original value" do
     @model.name = "Otto"
+    @model.status = "waiting"
     @model.save
     @model.name = "DudeFella ManGuy"
     @model.name = "Mr. Manfredgensonton"
+    @model.status = "processing"
+    @model.status = "finished"
     assert_equal ["Otto", "Mr. Manfredgensonton"], @model.name_change
+    assert_equal ["waiting", "finished"], @model.status_change
     assert_equal @model.name_was, "Otto"
   end
 
   test "using attribute_will_change! with a symbol" do
     @model.size = 1
-    assert @model.size_changed?
+    assert_predicate @model, :size_changed?
   end
 
   test "reload should reset all changes" do
@@ -201,7 +222,7 @@ class DirtyTest < ActiveModel::TestCase
 
     @model.restore_attributes
 
-    assert_not @model.changed?
+    assert_not_predicate @model, :changed?
     assert_equal "Dmitry", @model.name
     assert_equal "Red", @model.color
   end
@@ -215,7 +236,7 @@ class DirtyTest < ActiveModel::TestCase
 
     @model.restore_attributes(["name"])
 
-    assert @model.changed?
+    assert_predicate @model, :changed?
     assert_equal "Dmitry", @model.name
     assert_equal "White", @model.color
   end
diff --git a/activemodel/test/cases/errors_test.rb b/activemodel/test/cases/errors_test.rb
index d5c282b620..cb6a8c43d5 100644
--- a/activemodel/test/cases/errors_test.rb
+++ b/activemodel/test/cases/errors_test.rb
@@ -1,7 +1,6 @@
 # frozen_string_literal: true
 
 require "cases/helper"
-require "active_support/core_ext/string/strip"
 require "yaml"
 
 class ErrorsTest < ActiveModel::TestCase
@@ -83,7 +82,7 @@ class ErrorsTest < ActiveModel::TestCase
 
     assert_equal 1, person.errors.count
     person.errors.clear
-    assert person.errors.empty?
+    assert_empty person.errors
   end
 
   test "error access is indifferent" do
@@ -128,8 +127,8 @@ class ErrorsTest < ActiveModel::TestCase
   test "detecting whether there are errors with empty?, blank?, include?" do
     person = Person.new
     person.errors[:foo]
-    assert person.errors.empty?
-    assert person.errors.blank?
+    assert_empty person.errors
+    assert_predicate person.errors, :blank?
     assert_not_includes person.errors, :foo
   end
 
@@ -320,7 +319,7 @@ class ErrorsTest < ActiveModel::TestCase
 
   test "generate_message works without i18n_scope" do
     person = Person.new
-    assert !Person.respond_to?(:i18n_scope)
+    assert_not_respond_to Person, :i18n_scope
     assert_nothing_raised {
       person.errors.generate_message(:name, :blank)
     }
@@ -371,7 +370,7 @@ class ErrorsTest < ActiveModel::TestCase
 
     assert_equal 1, person.errors.details.count
     person.errors.clear
-    assert person.errors.details.empty?
+    assert_empty person.errors.details
   end
 
   test "copy errors" do
@@ -406,7 +405,7 @@ class ErrorsTest < ActiveModel::TestCase
   end
 
   test "errors are backward compatible with the Rails 4.2 format" do
-    yaml = <<-CODE.strip_heredoc
+    yaml = <<~CODE
     --- !ruby/object:ActiveModel::Errors
     base: &1 !ruby/object:ErrorsTest::Person
       errors: !ruby/object:ActiveModel::Errors
diff --git a/activemodel/test/cases/type/boolean_test.rb b/activemodel/test/cases/type/boolean_test.rb
index 2d33579595..2de0f53640 100644
--- a/activemodel/test/cases/type/boolean_test.rb
+++ b/activemodel/test/cases/type/boolean_test.rb
@@ -7,8 +7,8 @@ module ActiveModel
     class BooleanTest < ActiveModel::TestCase
       def test_type_cast_boolean
         type = Type::Boolean.new
-        assert type.cast("").nil?
-        assert type.cast(nil).nil?
+        assert_predicate type.cast(""), :nil?
+        assert_predicate type.cast(nil), :nil?
 
         assert type.cast(true)
         assert type.cast(1)
diff --git a/activemodel/test/cases/validations/absence_validation_test.rb b/activemodel/test/cases/validations/absence_validation_test.rb
index 801577474a..8bc4f4723a 100644
--- a/activemodel/test/cases/validations/absence_validation_test.rb
+++ b/activemodel/test/cases/validations/absence_validation_test.rb
@@ -17,16 +17,16 @@ class AbsenceValidationTest < ActiveModel::TestCase
     t = Topic.new
     t.title = "foo"
     t.content = "bar"
-    assert t.invalid?
+    assert_predicate t, :invalid?
     assert_equal ["must be blank"], t.errors[:title]
     assert_equal ["must be blank"], t.errors[:content]
     t.title = ""
     t.content = "something"
-    assert t.invalid?
+    assert_predicate t, :invalid?
     assert_equal ["must be blank"], t.errors[:content]
     assert_equal [], t.errors[:title]
     t.content = ""
-    assert t.valid?
+    assert_predicate t, :valid?
   end
 
   def test_validates_absence_of_with_array_arguments
@@ -34,7 +34,7 @@ class AbsenceValidationTest < ActiveModel::TestCase
     t = Topic.new
     t.title = "foo"
     t.content = "bar"
-    assert t.invalid?
+    assert_predicate t, :invalid?
     assert_equal ["must be blank"], t.errors[:title]
     assert_equal ["must be blank"], t.errors[:content]
   end
@@ -43,7 +43,7 @@ class AbsenceValidationTest < ActiveModel::TestCase
     Person.validates_absence_of :karma, message: "This string contains 'single' and \"double\" quotes"
     p = Person.new
     p.karma = "good"
-    assert p.invalid?
+    assert_predicate p, :invalid?
     assert_equal "This string contains 'single' and \"double\" quotes", p.errors[:karma].last
   end
 
@@ -51,19 +51,19 @@ class AbsenceValidationTest < ActiveModel::TestCase
     Person.validates_absence_of :karma
     p = Person.new
     p.karma = "good"
-    assert p.invalid?
+    assert_predicate p, :invalid?
     assert_equal ["must be blank"], p.errors[:karma]
     p.karma = nil
-    assert p.valid?
+    assert_predicate p, :valid?
   end
 
   def test_validates_absence_of_for_ruby_class_with_custom_reader
     CustomReader.validates_absence_of :karma
     p = CustomReader.new
     p[:karma] = "excellent"
-    assert p.invalid?
+    assert_predicate p, :invalid?
     assert_equal ["must be blank"], p.errors[:karma]
     p[:karma] = ""
-    assert p.valid?
+    assert_predicate p, :valid?
   end
 end
diff --git a/activemodel/test/cases/validations/acceptance_validation_test.rb b/activemodel/test/cases/validations/acceptance_validation_test.rb
index c5f54b1868..7662f996ae 100644
--- a/activemodel/test/cases/validations/acceptance_validation_test.rb
+++ b/activemodel/test/cases/validations/acceptance_validation_test.rb
@@ -15,54 +15,54 @@ class AcceptanceValidationTest < ActiveModel::TestCase
     Topic.validates_acceptance_of(:terms_of_service)
 
     t = Topic.new("title" => "We should not be confirmed")
-    assert t.valid?
+    assert_predicate t, :valid?
   end
 
   def test_terms_of_service_agreement
     Topic.validates_acceptance_of(:terms_of_service)
 
     t = Topic.new("title" => "We should be confirmed", "terms_of_service" => "")
-    assert t.invalid?
+    assert_predicate t, :invalid?
     assert_equal ["must be accepted"], t.errors[:terms_of_service]
 
     t.terms_of_service = "1"
-    assert t.valid?
+    assert_predicate t, :valid?
   end
 
   def test_eula
     Topic.validates_acceptance_of(:eula, message: "must be abided")
 
     t = Topic.new("title" => "We should be confirmed", "eula" => "")
-    assert t.invalid?
+    assert_predicate t, :invalid?
     assert_equal ["must be abided"], t.errors[:eula]
 
     t.eula = "1"
-    assert t.valid?
+    assert_predicate t, :valid?
   end
 
   def test_terms_of_service_agreement_with_accept_value
     Topic.validates_acceptance_of(:terms_of_service, accept: "I agree.")
 
     t = Topic.new("title" => "We should be confirmed", "terms_of_service" => "")
-    assert t.invalid?
+    assert_predicate t, :invalid?
     assert_equal ["must be accepted"], t.errors[:terms_of_service]
 
     t.terms_of_service = "I agree."
-    assert t.valid?
+    assert_predicate t, :valid?
   end
 
   def test_terms_of_service_agreement_with_multiple_accept_values
     Topic.validates_acceptance_of(:terms_of_service, accept: [1, "I concur."])
 
     t = Topic.new("title" => "We should be confirmed", "terms_of_service" => "")
-    assert t.invalid?
+    assert_predicate t, :invalid?
     assert_equal ["must be accepted"], t.errors[:terms_of_service]
 
     t.terms_of_service = 1
-    assert t.valid?
+    assert_predicate t, :valid?
 
     t.terms_of_service = "I concur."
-    assert t.valid?
+    assert_predicate t, :valid?
   end
 
   def test_validates_acceptance_of_for_ruby_class
@@ -71,11 +71,11 @@ class AcceptanceValidationTest < ActiveModel::TestCase
     p = Person.new
     p.karma = ""
 
-    assert p.invalid?
+    assert_predicate p, :invalid?
     assert_equal ["must be accepted"], p.errors[:karma]
 
     p.karma = "1"
-    assert p.valid?
+    assert_predicate p, :valid?
   ensure
     Person.clear_validators!
   end
@@ -83,6 +83,6 @@ class AcceptanceValidationTest < ActiveModel::TestCase
   def test_validates_acceptance_of_true
     Topic.validates_acceptance_of(:terms_of_service)
 
-    assert Topic.new(terms_of_service: true).valid?
+    assert_predicate Topic.new(terms_of_service: true), :valid?
   end
 end
diff --git a/activemodel/test/cases/validations/conditional_validation_test.rb b/activemodel/test/cases/validations/conditional_validation_test.rb
index caea8b65ef..1704db9a48 100644
--- a/activemodel/test/cases/validations/conditional_validation_test.rb
+++ b/activemodel/test/cases/validations/conditional_validation_test.rb
@@ -13,24 +13,24 @@ class ConditionalValidationTest < ActiveModel::TestCase
     # When the method returns true
     Topic.validates_length_of(:title, maximum: 5, too_long: "hoo %{count}", if: :condition_is_true)
     t = Topic.new("title" => "uhohuhoh", "content" => "whatever")
-    assert t.invalid?
-    assert t.errors[:title].any?
+    assert_predicate t, :invalid?
+    assert_predicate t.errors[:title], :any?
     assert_equal ["hoo 5"], t.errors["title"]
   end
 
   def test_if_validation_using_array_of_true_methods
     Topic.validates_length_of(:title, maximum: 5, too_long: "hoo %{count}", if: [:condition_is_true, :condition_is_true])
     t = Topic.new("title" => "uhohuhoh", "content" => "whatever")
-    assert t.invalid?
-    assert t.errors[:title].any?
+    assert_predicate t, :invalid?
+    assert_predicate t.errors[:title], :any?
     assert_equal ["hoo 5"], t.errors["title"]
   end
 
   def test_unless_validation_using_array_of_false_methods
     Topic.validates_length_of(:title, maximum: 5, too_long: "hoo %{count}", unless: [:condition_is_false, :condition_is_false])
     t = Topic.new("title" => "uhohuhoh", "content" => "whatever")
-    assert t.invalid?
-    assert t.errors[:title].any?
+    assert_predicate t, :invalid?
+    assert_predicate t.errors[:title], :any?
     assert_equal ["hoo 5"], t.errors["title"]
   end
 
@@ -38,21 +38,21 @@ class ConditionalValidationTest < ActiveModel::TestCase
     # When the method returns true
     Topic.validates_length_of(:title, maximum: 5, too_long: "hoo %{count}", unless: :condition_is_true)
     t = Topic.new("title" => "uhohuhoh", "content" => "whatever")
-    assert t.valid?
+    assert_predicate t, :valid?
     assert_empty t.errors[:title]
   end
 
   def test_if_validation_using_array_of_true_and_false_methods
     Topic.validates_length_of(:title, maximum: 5, too_long: "hoo %{count}", if: [:condition_is_true, :condition_is_false])
     t = Topic.new("title" => "uhohuhoh", "content" => "whatever")
-    assert t.valid?
+    assert_predicate t, :valid?
     assert_empty t.errors[:title]
   end
 
   def test_unless_validation_using_array_of_true_and_felse_methods
     Topic.validates_length_of(:title, maximum: 5, too_long: "hoo %{count}", unless: [:condition_is_true, :condition_is_false])
     t = Topic.new("title" => "uhohuhoh", "content" => "whatever")
-    assert t.valid?
+    assert_predicate t, :valid?
     assert_empty t.errors[:title]
   end
 
@@ -60,7 +60,7 @@ class ConditionalValidationTest < ActiveModel::TestCase
     # When the method returns false
     Topic.validates_length_of(:title, maximum: 5, too_long: "hoo %{count}", if: :condition_is_false)
     t = Topic.new("title" => "uhohuhoh", "content" => "whatever")
-    assert t.valid?
+    assert_predicate t, :valid?
     assert_empty t.errors[:title]
   end
 
@@ -68,8 +68,8 @@ class ConditionalValidationTest < ActiveModel::TestCase
     # When the method returns false
     Topic.validates_length_of(:title, maximum: 5, too_long: "hoo %{count}", unless: :condition_is_false)
     t = Topic.new("title" => "uhohuhoh", "content" => "whatever")
-    assert t.invalid?
-    assert t.errors[:title].any?
+    assert_predicate t, :invalid?
+    assert_predicate t.errors[:title], :any?
     assert_equal ["hoo 5"], t.errors["title"]
   end
 
@@ -78,8 +78,8 @@ class ConditionalValidationTest < ActiveModel::TestCase
     Topic.validates_length_of(:title, maximum: 5, too_long: "hoo %{count}",
       if: Proc.new { |r| r.content.size > 4 })
     t = Topic.new("title" => "uhohuhoh", "content" => "whatever")
-    assert t.invalid?
-    assert t.errors[:title].any?
+    assert_predicate t, :invalid?
+    assert_predicate t.errors[:title], :any?
     assert_equal ["hoo 5"], t.errors["title"]
   end
 
@@ -88,7 +88,7 @@ class ConditionalValidationTest < ActiveModel::TestCase
     Topic.validates_length_of(:title, maximum: 5, too_long: "hoo %{count}",
       unless: Proc.new { |r| r.content.size > 4 })
     t = Topic.new("title" => "uhohuhoh", "content" => "whatever")
-    assert t.valid?
+    assert_predicate t, :valid?
     assert_empty t.errors[:title]
   end
 
@@ -97,7 +97,7 @@ class ConditionalValidationTest < ActiveModel::TestCase
     Topic.validates_length_of(:title, maximum: 5, too_long: "hoo %{count}",
       if: Proc.new { |r| r.title != "uhohuhoh" })
     t = Topic.new("title" => "uhohuhoh", "content" => "whatever")
-    assert t.valid?
+    assert_predicate t, :valid?
     assert_empty t.errors[:title]
   end
 
@@ -106,23 +106,23 @@ class ConditionalValidationTest < ActiveModel::TestCase
     Topic.validates_length_of(:title, maximum: 5, too_long: "hoo %{count}",
       unless: Proc.new { |r| r.title != "uhohuhoh" })
     t = Topic.new("title" => "uhohuhoh", "content" => "whatever")
-    assert t.invalid?
-    assert t.errors[:title].any?
+    assert_predicate t, :invalid?
+    assert_predicate t.errors[:title], :any?
     assert_equal ["hoo 5"], t.errors["title"]
   end
 
   def test_validation_using_conbining_if_true_and_unless_true_conditions
     Topic.validates_length_of(:title, maximum: 5, too_long: "hoo %{count}", if: :condition_is_true, unless: :condition_is_true)
     t = Topic.new("title" => "uhohuhoh", "content" => "whatever")
-    assert t.valid?
+    assert_predicate t, :valid?
     assert_empty t.errors[:title]
   end
 
   def test_validation_using_conbining_if_true_and_unless_false_conditions
     Topic.validates_length_of(:title, maximum: 5, too_long: "hoo %{count}", if: :condition_is_true, unless: :condition_is_false)
     t = Topic.new("title" => "uhohuhoh", "content" => "whatever")
-    assert t.invalid?
-    assert t.errors[:title].any?
+    assert_predicate t, :invalid?
+    assert_predicate t.errors[:title], :any?
     assert_equal ["hoo 5"], t.errors["title"]
   end
 end
diff --git a/activemodel/test/cases/validations/confirmation_validation_test.rb b/activemodel/test/cases/validations/confirmation_validation_test.rb
index 8b2c65289b..8603a8ac5c 100644
--- a/activemodel/test/cases/validations/confirmation_validation_test.rb
+++ b/activemodel/test/cases/validations/confirmation_validation_test.rb
@@ -14,40 +14,40 @@ class ConfirmationValidationTest < ActiveModel::TestCase
     Topic.validates_confirmation_of(:title)
 
     t = Topic.new(author_name: "Plutarch")
-    assert t.valid?
+    assert_predicate t, :valid?
 
     t.title_confirmation = "Parallel Lives"
-    assert t.invalid?
+    assert_predicate t, :invalid?
 
     t.title_confirmation = nil
     t.title = "Parallel Lives"
-    assert t.valid?
+    assert_predicate t, :valid?
 
     t.title_confirmation = "Parallel Lives"
-    assert t.valid?
+    assert_predicate t, :valid?
   end
 
   def test_title_confirmation
     Topic.validates_confirmation_of(:title)
 
     t = Topic.new("title" => "We should be confirmed", "title_confirmation" => "")
-    assert t.invalid?
+    assert_predicate t, :invalid?
 
     t.title_confirmation = "We should be confirmed"
-    assert t.valid?
+    assert_predicate t, :valid?
   end
 
   def test_validates_confirmation_of_with_boolean_attribute
     Topic.validates_confirmation_of(:approved)
 
     t = Topic.new(approved: true, approved_confirmation: nil)
-    assert t.valid?
+    assert_predicate t, :valid?
 
     t.approved_confirmation = false
-    assert t.invalid?
+    assert_predicate t, :invalid?
 
     t.approved_confirmation = true
-    assert t.valid?
+    assert_predicate t, :valid?
   end
 
   def test_validates_confirmation_of_for_ruby_class
@@ -55,12 +55,12 @@ class ConfirmationValidationTest < ActiveModel::TestCase
 
     p = Person.new
     p.karma_confirmation = "None"
-    assert p.invalid?
+    assert_predicate p, :invalid?
 
     assert_equal ["doesn't match Karma"], p.errors[:karma_confirmation]
 
     p.karma = "None"
-    assert p.valid?
+    assert_predicate p, :valid?
   ensure
     Person.clear_validators!
   end
@@ -77,7 +77,7 @@ class ConfirmationValidationTest < ActiveModel::TestCase
       Topic.validates_confirmation_of(:title)
 
       t = Topic.new("title" => "We should be confirmed", "title_confirmation" => "")
-      assert t.invalid?
+      assert_predicate t, :invalid?
       assert_equal ["doesn't match Test Title"], t.errors[:title_confirmation]
     ensure
       I18n.load_path.replace @old_load_path
@@ -122,13 +122,13 @@ class ConfirmationValidationTest < ActiveModel::TestCase
     Topic.validates_confirmation_of(:title, case_sensitive: true)
 
     t = Topic.new(title: "title", title_confirmation: "Title")
-    assert t.invalid?
+    assert_predicate t, :invalid?
   end
 
   def test_title_confirmation_with_case_sensitive_option_false
     Topic.validates_confirmation_of(:title, case_sensitive: false)
 
     t = Topic.new(title: "title", title_confirmation: "Title")
-    assert t.valid?
+    assert_predicate t, :valid?
   end
 end
diff --git a/activemodel/test/cases/validations/exclusion_validation_test.rb b/activemodel/test/cases/validations/exclusion_validation_test.rb
index 68d611e904..50bd47065c 100644
--- a/activemodel/test/cases/validations/exclusion_validation_test.rb
+++ b/activemodel/test/cases/validations/exclusion_validation_test.rb
@@ -14,8 +14,8 @@ class ExclusionValidationTest < ActiveModel::TestCase
   def test_validates_exclusion_of
     Topic.validates_exclusion_of(:title, in: %w( abe monkey ))
 
-    assert Topic.new("title" => "something", "content" => "abc").valid?
-    assert Topic.new("title" => "monkey", "content" => "abc").invalid?
+    assert_predicate Topic.new("title" => "something", "content" => "abc"), :valid?
+    assert_predicate Topic.new("title" => "monkey", "content" => "abc"), :invalid?
   end
 
   def test_validates_exclusion_of_with_formatted_message
@@ -24,8 +24,8 @@ class ExclusionValidationTest < ActiveModel::TestCase
     assert Topic.new("title" => "something", "content" => "abc")
 
     t = Topic.new("title" => "monkey")
-    assert t.invalid?
-    assert t.errors[:title].any?
+    assert_predicate t, :invalid?
+    assert_predicate t.errors[:title], :any?
     assert_equal ["option monkey is restricted"], t.errors[:title]
   end
 
@@ -35,8 +35,8 @@ class ExclusionValidationTest < ActiveModel::TestCase
     assert Topic.new("title" => "something", "content" => "abc")
 
     t = Topic.new("title" => "monkey")
-    assert t.invalid?
-    assert t.errors[:title].any?
+    assert_predicate t, :invalid?
+    assert_predicate t.errors[:title], :any?
   end
 
   def test_validates_exclusion_of_for_ruby_class
@@ -44,12 +44,12 @@ class ExclusionValidationTest < ActiveModel::TestCase
 
     p = Person.new
     p.karma = "abe"
-    assert p.invalid?
+    assert_predicate p, :invalid?
 
     assert_equal ["is reserved"], p.errors[:karma]
 
     p.karma = "Lifo"
-    assert p.valid?
+    assert_predicate p, :valid?
   ensure
     Person.clear_validators!
   end
@@ -60,26 +60,26 @@ class ExclusionValidationTest < ActiveModel::TestCase
     t = Topic.new
     t.title = "elephant"
     t.author_name = "sikachu"
-    assert t.invalid?
+    assert_predicate t, :invalid?
 
     t.title = "wasabi"
-    assert t.valid?
+    assert_predicate t, :valid?
   end
 
   def test_validates_exclusion_of_with_range
     Topic.validates_exclusion_of :content, in: ("a".."g")
 
-    assert Topic.new(content: "g").invalid?
-    assert Topic.new(content: "h").valid?
+    assert_predicate Topic.new(content: "g"), :invalid?
+    assert_predicate Topic.new(content: "h"), :valid?
   end
 
   def test_validates_exclusion_of_with_time_range
     Topic.validates_exclusion_of :created_at, in: 6.days.ago..2.days.ago
 
-    assert Topic.new(created_at: 5.days.ago).invalid?
-    assert Topic.new(created_at: 3.days.ago).invalid?
-    assert Topic.new(created_at: 7.days.ago).valid?
-    assert Topic.new(created_at: 1.day.ago).valid?
+    assert_predicate Topic.new(created_at: 5.days.ago), :invalid?
+    assert_predicate Topic.new(created_at: 3.days.ago), :invalid?
+    assert_predicate Topic.new(created_at: 7.days.ago), :valid?
+    assert_predicate Topic.new(created_at: 1.day.ago), :valid?
   end
 
   def test_validates_inclusion_of_with_symbol
@@ -92,7 +92,7 @@ class ExclusionValidationTest < ActiveModel::TestCase
       %w(abe)
     end
 
-    assert p.invalid?
+    assert_predicate p, :invalid?
     assert_equal ["is reserved"], p.errors[:karma]
 
     p = Person.new
@@ -102,7 +102,7 @@ class ExclusionValidationTest < ActiveModel::TestCase
       %w()
     end
 
-    assert p.valid?
+    assert_predicate p, :valid?
   ensure
     Person.clear_validators!
   end
diff --git a/activemodel/test/cases/validations/format_validation_test.rb b/activemodel/test/cases/validations/format_validation_test.rb
index b0de80a6fc..2a7088b3e8 100644
--- a/activemodel/test/cases/validations/format_validation_test.rb
+++ b/activemodel/test/cases/validations/format_validation_test.rb
@@ -16,22 +16,22 @@ class FormatValidationTest < ActiveModel::TestCase
     t = Topic.new("title" => "i'm incorrect", "content" => "Validation macros rule!")
     assert t.invalid?, "Shouldn't be valid"
     assert_equal ["is bad data"], t.errors[:title]
-    assert t.errors[:content].empty?
+    assert_empty t.errors[:content]
 
     t.title = "Validation macros rule!"
 
-    assert t.valid?
-    assert t.errors[:title].empty?
+    assert_predicate t, :valid?
+    assert_empty t.errors[:title]
 
     assert_raise(ArgumentError) { Topic.validates_format_of(:title, :content) }
   end
 
   def test_validate_format_with_allow_blank
     Topic.validates_format_of(:title, with: /\AValidation\smacros \w+!\z/, allow_blank: true)
-    assert Topic.new("title" => "Shouldn't be valid").invalid?
-    assert Topic.new("title" => "").valid?
-    assert Topic.new("title" => nil).valid?
-    assert Topic.new("title" => "Validation macros rule!").valid?
+    assert_predicate Topic.new("title" => "Shouldn't be valid"), :invalid?
+    assert_predicate Topic.new("title" => ""), :valid?
+    assert_predicate Topic.new("title" => nil), :valid?
+    assert_predicate Topic.new("title" => "Validation macros rule!"), :valid?
   end
 
   # testing ticket #3142
@@ -42,7 +42,7 @@ class FormatValidationTest < ActiveModel::TestCase
     assert t.invalid?, "Shouldn't be valid"
 
     assert_equal ["is bad data"], t.errors[:title]
-    assert t.errors[:content].empty?
+    assert_empty t.errors[:content]
 
     t.title = "-11"
     assert t.invalid?, "Shouldn't be valid"
@@ -58,14 +58,14 @@ class FormatValidationTest < ActiveModel::TestCase
 
     t.title = "1"
 
-    assert t.valid?
-    assert t.errors[:title].empty?
+    assert_predicate t, :valid?
+    assert_empty t.errors[:title]
   end
 
   def test_validate_format_with_formatted_message
     Topic.validates_format_of(:title, with: /\AValid Title\z/, message: "can't be %{value}")
     t = Topic.new(title: "Invalid title")
-    assert t.invalid?
+    assert_predicate t, :invalid?
     assert_equal ["can't be Invalid title"], t.errors[:title]
   end
 
@@ -114,10 +114,10 @@ class FormatValidationTest < ActiveModel::TestCase
     t = Topic.new
     t.title = "digit"
     t.content = "Pixies"
-    assert t.invalid?
+    assert_predicate t, :invalid?
 
     t.content = "1234"
-    assert t.valid?
+    assert_predicate t, :valid?
   end
 
   def test_validates_format_of_without_lambda
@@ -126,10 +126,10 @@ class FormatValidationTest < ActiveModel::TestCase
     t = Topic.new
     t.title = "characters"
     t.content = "1234"
-    assert t.invalid?
+    assert_predicate t, :invalid?
 
     t.content = "Pixies"
-    assert t.valid?
+    assert_predicate t, :valid?
   end
 
   def test_validates_format_of_for_ruby_class
@@ -137,12 +137,12 @@ class FormatValidationTest < ActiveModel::TestCase
 
     p = Person.new
     p.karma = "Pixies"
-    assert p.invalid?
+    assert_predicate p, :invalid?
 
     assert_equal ["is invalid"], p.errors[:karma]
 
     p.karma = "1234"
-    assert p.valid?
+    assert_predicate p, :valid?
   ensure
     Person.clear_validators!
   end
diff --git a/activemodel/test/cases/validations/inclusion_validation_test.rb b/activemodel/test/cases/validations/inclusion_validation_test.rb
index 94df0649a9..daad76759f 100644
--- a/activemodel/test/cases/validations/inclusion_validation_test.rb
+++ b/activemodel/test/cases/validations/inclusion_validation_test.rb
@@ -13,61 +13,61 @@ class InclusionValidationTest < ActiveModel::TestCase
 
   def test_validates_inclusion_of_range
     Topic.validates_inclusion_of(:title, in: "aaa".."bbb")
-    assert Topic.new("title" => "bbc", "content" => "abc").invalid?
-    assert Topic.new("title" => "aa", "content" => "abc").invalid?
-    assert Topic.new("title" => "aaab", "content" => "abc").invalid?
-    assert Topic.new("title" => "aaa", "content" => "abc").valid?
-    assert Topic.new("title" => "abc", "content" => "abc").valid?
-    assert Topic.new("title" => "bbb", "content" => "abc").valid?
+    assert_predicate Topic.new("title" => "bbc", "content" => "abc"), :invalid?
+    assert_predicate Topic.new("title" => "aa", "content" => "abc"), :invalid?
+    assert_predicate Topic.new("title" => "aaab", "content" => "abc"), :invalid?
+    assert_predicate Topic.new("title" => "aaa", "content" => "abc"), :valid?
+    assert_predicate Topic.new("title" => "abc", "content" => "abc"), :valid?
+    assert_predicate Topic.new("title" => "bbb", "content" => "abc"), :valid?
   end
 
   def test_validates_inclusion_of_time_range
     range_begin = 1.year.ago
     range_end = Time.now
     Topic.validates_inclusion_of(:created_at, in: range_begin..range_end)
-    assert Topic.new(title: "aaa", created_at: 2.years.ago).invalid?
-    assert Topic.new(title: "aaa", created_at: 3.months.ago).valid?
-    assert Topic.new(title: "aaa", created_at: 37.weeks.from_now).invalid?
-    assert Topic.new(title: "aaa", created_at: range_begin).valid?
-    assert Topic.new(title: "aaa", created_at: range_end).valid?
+    assert_predicate Topic.new(title: "aaa", created_at: 2.years.ago), :invalid?
+    assert_predicate Topic.new(title: "aaa", created_at: 3.months.ago), :valid?
+    assert_predicate Topic.new(title: "aaa", created_at: 37.weeks.from_now), :invalid?
+    assert_predicate Topic.new(title: "aaa", created_at: range_begin), :valid?
+    assert_predicate Topic.new(title: "aaa", created_at: range_end), :valid?
   end
 
   def test_validates_inclusion_of_date_range
     range_begin = 1.year.until(Date.today)
     range_end = Date.today
     Topic.validates_inclusion_of(:created_at, in: range_begin..range_end)
-    assert Topic.new(title: "aaa", created_at: 2.years.until(Date.today)).invalid?
-    assert Topic.new(title: "aaa", created_at: 3.months.until(Date.today)).valid?
-    assert Topic.new(title: "aaa", created_at: 37.weeks.since(Date.today)).invalid?
-    assert Topic.new(title: "aaa", created_at: 1.year.until(Date.today)).valid?
-    assert Topic.new(title: "aaa", created_at: Date.today).valid?
-    assert Topic.new(title: "aaa", created_at: range_begin).valid?
-    assert Topic.new(title: "aaa", created_at: range_end).valid?
+    assert_predicate Topic.new(title: "aaa", created_at: 2.years.until(Date.today)), :invalid?
+    assert_predicate Topic.new(title: "aaa", created_at: 3.months.until(Date.today)), :valid?
+    assert_predicate Topic.new(title: "aaa", created_at: 37.weeks.since(Date.today)), :invalid?
+    assert_predicate Topic.new(title: "aaa", created_at: 1.year.until(Date.today)), :valid?
+    assert_predicate Topic.new(title: "aaa", created_at: Date.today), :valid?
+    assert_predicate Topic.new(title: "aaa", created_at: range_begin), :valid?
+    assert_predicate Topic.new(title: "aaa", created_at: range_end), :valid?
   end
 
   def test_validates_inclusion_of_date_time_range
     range_begin = 1.year.until(DateTime.current)
     range_end = DateTime.current
     Topic.validates_inclusion_of(:created_at, in: range_begin..range_end)
-    assert Topic.new(title: "aaa", created_at: 2.years.until(DateTime.current)).invalid?
-    assert Topic.new(title: "aaa", created_at: 3.months.until(DateTime.current)).valid?
-    assert Topic.new(title: "aaa", created_at: 37.weeks.since(DateTime.current)).invalid?
-    assert Topic.new(title: "aaa", created_at: range_begin).valid?
-    assert Topic.new(title: "aaa", created_at: range_end).valid?
+    assert_predicate Topic.new(title: "aaa", created_at: 2.years.until(DateTime.current)), :invalid?
+    assert_predicate Topic.new(title: "aaa", created_at: 3.months.until(DateTime.current)), :valid?
+    assert_predicate Topic.new(title: "aaa", created_at: 37.weeks.since(DateTime.current)), :invalid?
+    assert_predicate Topic.new(title: "aaa", created_at: range_begin), :valid?
+    assert_predicate Topic.new(title: "aaa", created_at: range_end), :valid?
   end
 
   def test_validates_inclusion_of
     Topic.validates_inclusion_of(:title, in: %w( a b c d e f g ))
 
-    assert Topic.new("title" => "a!", "content" => "abc").invalid?
-    assert Topic.new("title" => "a b", "content" => "abc").invalid?
-    assert Topic.new("title" => nil, "content" => "def").invalid?
+    assert_predicate Topic.new("title" => "a!", "content" => "abc"), :invalid?
+    assert_predicate Topic.new("title" => "a b", "content" => "abc"), :invalid?
+    assert_predicate Topic.new("title" => nil, "content" => "def"), :invalid?
 
     t = Topic.new("title" => "a", "content" => "I know you are but what am I?")
-    assert t.valid?
+    assert_predicate t, :valid?
     t.title = "uhoh"
-    assert t.invalid?
-    assert t.errors[:title].any?
+    assert_predicate t, :invalid?
+    assert_predicate t.errors[:title], :any?
     assert_equal ["is not included in the list"], t.errors[:title]
 
     assert_raise(ArgumentError) { Topic.validates_inclusion_of(:title, in: nil) }
@@ -81,30 +81,30 @@ class InclusionValidationTest < ActiveModel::TestCase
   def test_validates_inclusion_of_with_allow_nil
     Topic.validates_inclusion_of(:title, in: %w( a b c d e f g ), allow_nil: true)
 
-    assert Topic.new("title" => "a!", "content" => "abc").invalid?
-    assert Topic.new("title" => "",   "content" => "abc").invalid?
-    assert Topic.new("title" => nil,  "content" => "abc").valid?
+    assert_predicate Topic.new("title" => "a!", "content" => "abc"), :invalid?
+    assert_predicate Topic.new("title" => "",   "content" => "abc"), :invalid?
+    assert_predicate Topic.new("title" => nil,  "content" => "abc"), :valid?
   end
 
   def test_validates_inclusion_of_with_formatted_message
     Topic.validates_inclusion_of(:title, in: %w( a b c d e f g ), message: "option %{value} is not in the list")
 
-    assert Topic.new("title" => "a", "content" => "abc").valid?
+    assert_predicate Topic.new("title" => "a", "content" => "abc"), :valid?
 
     t = Topic.new("title" => "uhoh", "content" => "abc")
-    assert t.invalid?
-    assert t.errors[:title].any?
+    assert_predicate t, :invalid?
+    assert_predicate t.errors[:title], :any?
     assert_equal ["option uhoh is not in the list"], t.errors[:title]
   end
 
   def test_validates_inclusion_of_with_within_option
     Topic.validates_inclusion_of(:title, within: %w( a b c d e f g ))
 
-    assert Topic.new("title" => "a", "content" => "abc").valid?
+    assert_predicate Topic.new("title" => "a", "content" => "abc"), :valid?
 
     t = Topic.new("title" => "uhoh", "content" => "abc")
-    assert t.invalid?
-    assert t.errors[:title].any?
+    assert_predicate t, :invalid?
+    assert_predicate t.errors[:title], :any?
   end
 
   def test_validates_inclusion_of_for_ruby_class
@@ -112,12 +112,12 @@ class InclusionValidationTest < ActiveModel::TestCase
 
     p = Person.new
     p.karma = "Lifo"
-    assert p.invalid?
+    assert_predicate p, :invalid?
 
     assert_equal ["is not included in the list"], p.errors[:karma]
 
     p.karma = "monkey"
-    assert p.valid?
+    assert_predicate p, :valid?
   ensure
     Person.clear_validators!
   end
@@ -128,10 +128,10 @@ class InclusionValidationTest < ActiveModel::TestCase
     t = Topic.new
     t.title = "wasabi"
     t.author_name = "sikachu"
-    assert t.invalid?
+    assert_predicate t, :invalid?
 
     t.title = "elephant"
-    assert t.valid?
+    assert_predicate t, :valid?
   end
 
   def test_validates_inclusion_of_with_symbol
@@ -144,7 +144,7 @@ class InclusionValidationTest < ActiveModel::TestCase
       %w()
     end
 
-    assert p.invalid?
+    assert_predicate p, :invalid?
     assert_equal ["is not included in the list"], p.errors[:karma]
 
     p = Person.new
@@ -154,7 +154,7 @@ class InclusionValidationTest < ActiveModel::TestCase
       %w(Lifo)
     end
 
-    assert p.valid?
+    assert_predicate p, :valid?
   ensure
     Person.clear_validators!
   end
diff --git a/activemodel/test/cases/validations/length_validation_test.rb b/activemodel/test/cases/validations/length_validation_test.rb
index 42f76f3e3c..774a2cde74 100644
--- a/activemodel/test/cases/validations/length_validation_test.rb
+++ b/activemodel/test/cases/validations/length_validation_test.rb
@@ -13,153 +13,153 @@ class LengthValidationTest < ActiveModel::TestCase
   def test_validates_length_of_with_allow_nil
     Topic.validates_length_of(:title, is: 5, allow_nil: true)
 
-    assert Topic.new("title" => "ab").invalid?
-    assert Topic.new("title" => "").invalid?
-    assert Topic.new("title" => nil).valid?
-    assert Topic.new("title" => "abcde").valid?
+    assert_predicate Topic.new("title" => "ab"), :invalid?
+    assert_predicate Topic.new("title" => ""), :invalid?
+    assert_predicate Topic.new("title" => nil), :valid?
+    assert_predicate Topic.new("title" => "abcde"), :valid?
   end
 
   def test_validates_length_of_with_allow_blank
     Topic.validates_length_of(:title, is: 5, allow_blank: true)
 
-    assert Topic.new("title" => "ab").invalid?
-    assert Topic.new("title" => "").valid?
-    assert Topic.new("title" => nil).valid?
-    assert Topic.new("title" => "abcde").valid?
+    assert_predicate Topic.new("title" => "ab"), :invalid?
+    assert_predicate Topic.new("title" => ""), :valid?
+    assert_predicate Topic.new("title" => nil), :valid?
+    assert_predicate Topic.new("title" => "abcde"), :valid?
   end
 
   def test_validates_length_of_using_minimum
     Topic.validates_length_of :title, minimum: 5
 
     t = Topic.new("title" => "valid", "content" => "whatever")
-    assert t.valid?
+    assert_predicate t, :valid?
 
     t.title = "not"
-    assert t.invalid?
-    assert t.errors[:title].any?
+    assert_predicate t, :invalid?
+    assert_predicate t.errors[:title], :any?
     assert_equal ["is too short (minimum is 5 characters)"], t.errors[:title]
 
     t.title = ""
-    assert t.invalid?
-    assert t.errors[:title].any?
+    assert_predicate t, :invalid?
+    assert_predicate t.errors[:title], :any?
     assert_equal ["is too short (minimum is 5 characters)"], t.errors[:title]
 
     t.title = nil
-    assert t.invalid?
-    assert t.errors[:title].any?
+    assert_predicate t, :invalid?
+    assert_predicate t.errors[:title], :any?
     assert_equal ["is too short (minimum is 5 characters)"], t.errors["title"]
   end
 
   def test_validates_length_of_using_maximum_should_allow_nil
     Topic.validates_length_of :title, maximum: 10
     t = Topic.new
-    assert t.valid?
+    assert_predicate t, :valid?
   end
 
   def test_optionally_validates_length_of_using_minimum
     Topic.validates_length_of :title, minimum: 5, allow_nil: true
 
     t = Topic.new("title" => "valid", "content" => "whatever")
-    assert t.valid?
+    assert_predicate t, :valid?
 
     t.title = nil
-    assert t.valid?
+    assert_predicate t, :valid?
   end
 
   def test_validates_length_of_using_maximum
     Topic.validates_length_of :title, maximum: 5
 
     t = Topic.new("title" => "valid", "content" => "whatever")
-    assert t.valid?
+    assert_predicate t, :valid?
 
     t.title = "notvalid"
-    assert t.invalid?
-    assert t.errors[:title].any?
+    assert_predicate t, :invalid?
+    assert_predicate t.errors[:title], :any?
     assert_equal ["is too long (maximum is 5 characters)"], t.errors[:title]
 
     t.title = ""
-    assert t.valid?
+    assert_predicate t, :valid?
   end
 
   def test_optionally_validates_length_of_using_maximum
     Topic.validates_length_of :title, maximum: 5, allow_nil: true
 
     t = Topic.new("title" => "valid", "content" => "whatever")
-    assert t.valid?
+    assert_predicate t, :valid?
 
     t.title = nil
-    assert t.valid?
+    assert_predicate t, :valid?
   end
 
   def test_validates_length_of_using_within
     Topic.validates_length_of(:title, :content, within: 3..5)
 
     t = Topic.new("title" => "a!", "content" => "I'm ooooooooh so very long")
-    assert t.invalid?
+    assert_predicate t, :invalid?
     assert_equal ["is too short (minimum is 3 characters)"], t.errors[:title]
     assert_equal ["is too long (maximum is 5 characters)"], t.errors[:content]
 
     t.title = nil
     t.content = nil
-    assert t.invalid?
+    assert_predicate t, :invalid?
     assert_equal ["is too short (minimum is 3 characters)"], t.errors[:title]
     assert_equal ["is too short (minimum is 3 characters)"], t.errors[:content]
 
     t.title = "abe"
     t.content = "mad"
-    assert t.valid?
+    assert_predicate t, :valid?
   end
 
   def test_validates_length_of_using_within_with_exclusive_range
     Topic.validates_length_of(:title, within: 4...10)
 
     t = Topic.new("title" => "9 chars!!")
-    assert t.valid?
+    assert_predicate t, :valid?
 
     t.title = "Now I'm 10"
-    assert t.invalid?
+    assert_predicate t, :invalid?
     assert_equal ["is too long (maximum is 9 characters)"], t.errors[:title]
 
     t.title = "Four"
-    assert t.valid?
+    assert_predicate t, :valid?
   end
 
   def test_optionally_validates_length_of_using_within
     Topic.validates_length_of :title, :content, within: 3..5, allow_nil: true
 
     t = Topic.new("title" => "abc", "content" => "abcd")
-    assert t.valid?
+    assert_predicate t, :valid?
 
     t.title = nil
-    assert t.valid?
+    assert_predicate t, :valid?
   end
 
   def test_validates_length_of_using_is
     Topic.validates_length_of :title, is: 5
 
     t = Topic.new("title" => "valid", "content" => "whatever")
-    assert t.valid?
+    assert_predicate t, :valid?
 
     t.title = "notvalid"
-    assert t.invalid?
-    assert t.errors[:title].any?
+    assert_predicate t, :invalid?
+    assert_predicate t.errors[:title], :any?
     assert_equal ["is the wrong length (should be 5 characters)"], t.errors[:title]
 
     t.title = ""
-    assert t.invalid?
+    assert_predicate t, :invalid?
 
     t.title = nil
-    assert t.invalid?
+    assert_predicate t, :invalid?
   end
 
   def test_optionally_validates_length_of_using_is
     Topic.validates_length_of :title, is: 5, allow_nil: true
 
     t = Topic.new("title" => "valid", "content" => "whatever")
-    assert t.valid?
+    assert_predicate t, :valid?
 
     t.title = nil
-    assert t.valid?
+    assert_predicate t, :valid?
   end
 
   def test_validates_length_of_using_bignum
@@ -187,45 +187,45 @@ class LengthValidationTest < ActiveModel::TestCase
   def test_validates_length_of_custom_errors_for_minimum_with_message
     Topic.validates_length_of(:title, minimum: 5, message: "boo %{count}")
     t = Topic.new("title" => "uhoh", "content" => "whatever")
-    assert t.invalid?
-    assert t.errors[:title].any?
+    assert_predicate t, :invalid?
+    assert_predicate t.errors[:title], :any?
     assert_equal ["boo 5"], t.errors[:title]
   end
 
   def test_validates_length_of_custom_errors_for_minimum_with_too_short
     Topic.validates_length_of(:title, minimum: 5, too_short: "hoo %{count}")
     t = Topic.new("title" => "uhoh", "content" => "whatever")
-    assert t.invalid?
-    assert t.errors[:title].any?
+    assert_predicate t, :invalid?
+    assert_predicate t.errors[:title], :any?
     assert_equal ["hoo 5"], t.errors[:title]
   end
 
   def test_validates_length_of_custom_errors_for_maximum_with_message
     Topic.validates_length_of(:title, maximum: 5, message: "boo %{count}")
     t = Topic.new("title" => "uhohuhoh", "content" => "whatever")
-    assert t.invalid?
-    assert t.errors[:title].any?
+    assert_predicate t, :invalid?
+    assert_predicate t.errors[:title], :any?
     assert_equal ["boo 5"], t.errors[:title]
   end
 
   def test_validates_length_of_custom_errors_for_in
     Topic.validates_length_of(:title, in: 10..20, message: "hoo %{count}")
     t = Topic.new("title" => "uhohuhoh", "content" => "whatever")
-    assert t.invalid?
-    assert t.errors[:title].any?
+    assert_predicate t, :invalid?
+    assert_predicate t.errors[:title], :any?
     assert_equal ["hoo 10"], t.errors["title"]
 
     t = Topic.new("title" => "uhohuhohuhohuhohuhohuhohuhohuhoh", "content" => "whatever")
-    assert t.invalid?
-    assert t.errors[:title].any?
+    assert_predicate t, :invalid?
+    assert_predicate t.errors[:title], :any?
     assert_equal ["hoo 20"], t.errors["title"]
   end
 
   def test_validates_length_of_custom_errors_for_maximum_with_too_long
     Topic.validates_length_of(:title, maximum: 5, too_long: "hoo %{count}")
     t = Topic.new("title" => "uhohuhoh", "content" => "whatever")
-    assert t.invalid?
-    assert t.errors[:title].any?
+    assert_predicate t, :invalid?
+    assert_predicate t.errors[:title], :any?
     assert_equal ["hoo 5"], t.errors["title"]
   end
 
@@ -233,29 +233,29 @@ class LengthValidationTest < ActiveModel::TestCase
     Topic.validates_length_of :title, minimum: 3, maximum: 5, too_short: "too short", too_long: "too long"
 
     t = Topic.new(title: "a")
-    assert t.invalid?
-    assert t.errors[:title].any?
+    assert_predicate t, :invalid?
+    assert_predicate t.errors[:title], :any?
     assert_equal ["too short"], t.errors["title"]
 
     t = Topic.new(title: "aaaaaa")
-    assert t.invalid?
-    assert t.errors[:title].any?
+    assert_predicate t, :invalid?
+    assert_predicate t.errors[:title], :any?
     assert_equal ["too long"], t.errors["title"]
   end
 
   def test_validates_length_of_custom_errors_for_is_with_message
     Topic.validates_length_of(:title, is: 5, message: "boo %{count}")
     t = Topic.new("title" => "uhohuhoh", "content" => "whatever")
-    assert t.invalid?
-    assert t.errors[:title].any?
+    assert_predicate t, :invalid?
+    assert_predicate t.errors[:title], :any?
     assert_equal ["boo 5"], t.errors["title"]
   end
 
   def test_validates_length_of_custom_errors_for_is_with_wrong_length
     Topic.validates_length_of(:title, is: 5, wrong_length: "hoo %{count}")
     t = Topic.new("title" => "uhohuhoh", "content" => "whatever")
-    assert t.invalid?
-    assert t.errors[:title].any?
+    assert_predicate t, :invalid?
+    assert_predicate t.errors[:title], :any?
     assert_equal ["hoo 5"], t.errors["title"]
   end
 
@@ -263,11 +263,11 @@ class LengthValidationTest < ActiveModel::TestCase
     Topic.validates_length_of :title, minimum: 5
 
     t = Topic.new("title" => "一二三四五", "content" => "whatever")
-    assert t.valid?
+    assert_predicate t, :valid?
 
     t.title = "一二三四"
-    assert t.invalid?
-    assert t.errors[:title].any?
+    assert_predicate t, :invalid?
+    assert_predicate t.errors[:title], :any?
     assert_equal ["is too short (minimum is 5 characters)"], t.errors["title"]
   end
 
@@ -275,11 +275,11 @@ class LengthValidationTest < ActiveModel::TestCase
     Topic.validates_length_of :title, maximum: 5
 
     t = Topic.new("title" => "一二三四五", "content" => "whatever")
-    assert t.valid?
+    assert_predicate t, :valid?
 
     t.title = "一二34五六"
-    assert t.invalid?
-    assert t.errors[:title].any?
+    assert_predicate t, :invalid?
+    assert_predicate t.errors[:title], :any?
     assert_equal ["is too long (maximum is 5 characters)"], t.errors["title"]
   end
 
@@ -287,12 +287,12 @@ class LengthValidationTest < ActiveModel::TestCase
     Topic.validates_length_of(:title, :content, within: 3..5)
 
     t = Topic.new("title" => "一二", "content" => "12三四五六七")
-    assert t.invalid?
+    assert_predicate t, :invalid?
     assert_equal ["is too short (minimum is 3 characters)"], t.errors[:title]
     assert_equal ["is too long (maximum is 5 characters)"], t.errors[:content]
     t.title = "一二三"
     t.content = "12三"
-    assert t.valid?
+    assert_predicate t, :valid?
   end
 
   def test_optionally_validates_length_of_using_within_utf8
@@ -312,11 +312,11 @@ class LengthValidationTest < ActiveModel::TestCase
     Topic.validates_length_of :title, is: 5
 
     t = Topic.new("title" => "一二345", "content" => "whatever")
-    assert t.valid?
+    assert_predicate t, :valid?
 
     t.title = "一二345六"
-    assert t.invalid?
-    assert t.errors[:title].any?
+    assert_predicate t, :invalid?
+    assert_predicate t.errors[:title], :any?
     assert_equal ["is the wrong length (should be 5 characters)"], t.errors["title"]
   end
 
@@ -324,11 +324,11 @@ class LengthValidationTest < ActiveModel::TestCase
     Topic.validates_length_of(:approved, is: 4)
 
     t = Topic.new("title" => "uhohuhoh", "content" => "whatever", approved: 1)
-    assert t.invalid?
-    assert t.errors[:approved].any?
+    assert_predicate t, :invalid?
+    assert_predicate t.errors[:approved], :any?
 
     t = Topic.new("title" => "uhohuhoh", "content" => "whatever", approved: 1234)
-    assert t.valid?
+    assert_predicate t, :valid?
   end
 
   def test_validates_length_of_for_ruby_class
@@ -336,12 +336,12 @@ class LengthValidationTest < ActiveModel::TestCase
 
     p = Person.new
     p.karma = "Pix"
-    assert p.invalid?
+    assert_predicate p, :invalid?
 
     assert_equal ["is too short (minimum is 5 characters)"], p.errors[:karma]
 
     p.karma = "The Smiths"
-    assert p.valid?
+    assert_predicate p, :valid?
   ensure
     Person.clear_validators!
   end
@@ -350,80 +350,80 @@ class LengthValidationTest < ActiveModel::TestCase
     Topic.validates_length_of(:title, within: 5..Float::INFINITY)
 
     t = Topic.new("title" => "1234")
-    assert t.invalid?
-    assert t.errors[:title].any?
+    assert_predicate t, :invalid?
+    assert_predicate t.errors[:title], :any?
 
     t.title = "12345"
-    assert t.valid?
+    assert_predicate t, :valid?
 
     Topic.validates_length_of(:author_name, maximum: Float::INFINITY)
 
-    assert t.valid?
+    assert_predicate t, :valid?
 
     t.author_name = "A very long author name that should still be valid." * 100
-    assert t.valid?
+    assert_predicate t, :valid?
   end
 
   def test_validates_length_of_using_maximum_should_not_allow_nil_when_nil_not_allowed
     Topic.validates_length_of :title, maximum: 10, allow_nil: false
     t = Topic.new
-    assert t.invalid?
+    assert_predicate t, :invalid?
   end
 
   def test_validates_length_of_using_maximum_should_not_allow_nil_and_empty_string_when_blank_not_allowed
     Topic.validates_length_of :title, maximum: 10, allow_blank: false
     t = Topic.new
-    assert t.invalid?
+    assert_predicate t, :invalid?
 
     t.title = ""
-    assert t.invalid?
+    assert_predicate t, :invalid?
   end
 
   def test_validates_length_of_using_both_minimum_and_maximum_should_not_allow_nil
     Topic.validates_length_of :title, minimum: 5, maximum: 10
     t = Topic.new
-    assert t.invalid?
+    assert_predicate t, :invalid?
   end
 
   def test_validates_length_of_using_minimum_0_should_not_allow_nil
     Topic.validates_length_of :title, minimum: 0
     t = Topic.new
-    assert t.invalid?
+    assert_predicate t, :invalid?
 
     t.title = ""
-    assert t.valid?
+    assert_predicate t, :valid?
   end
 
   def test_validates_length_of_using_is_0_should_not_allow_nil
     Topic.validates_length_of :title, is: 0
     t = Topic.new
-    assert t.invalid?
+    assert_predicate t, :invalid?
 
     t.title = ""
-    assert t.valid?
+    assert_predicate t, :valid?
   end
 
   def test_validates_with_diff_in_option
     Topic.validates_length_of(:title, is: 5)
     Topic.validates_length_of(:title, is: 5, if: Proc.new { false })
 
-    assert Topic.new("title" => "david").valid?
-    assert Topic.new("title" => "david2").invalid?
+    assert_predicate Topic.new("title" => "david"), :valid?
+    assert_predicate Topic.new("title" => "david2"), :invalid?
   end
 
   def test_validates_length_of_using_proc_as_maximum
     Topic.validates_length_of :title, maximum: ->(model) { 5 }
 
     t = Topic.new("title" => "valid", "content" => "whatever")
-    assert t.valid?
+    assert_predicate t, :valid?
 
     t.title = "notvalid"
-    assert t.invalid?
-    assert t.errors[:title].any?
+    assert_predicate t, :invalid?
+    assert_predicate t.errors[:title], :any?
     assert_equal ["is too long (maximum is 5 characters)"], t.errors[:title]
 
     t.title = ""
-    assert t.valid?
+    assert_predicate t, :valid?
   end
 
   def test_validates_length_of_using_proc_as_maximum_with_model_method
@@ -431,14 +431,14 @@ class LengthValidationTest < ActiveModel::TestCase
     Topic.validates_length_of :title, maximum: Proc.new(&:max_title_length)
 
     t = Topic.new("title" => "valid", "content" => "whatever")
-    assert t.valid?
+    assert_predicate t, :valid?
 
     t.title = "notvalid"
-    assert t.invalid?
-    assert t.errors[:title].any?
+    assert_predicate t, :invalid?
+    assert_predicate t.errors[:title], :any?
     assert_equal ["is too long (maximum is 5 characters)"], t.errors[:title]
 
     t.title = ""
-    assert t.valid?
+    assert_predicate t, :valid?
   end
 end
diff --git a/activemodel/test/cases/validations/numericality_validation_test.rb b/activemodel/test/cases/validations/numericality_validation_test.rb
index 5413255e6b..01b78ae72e 100644
--- a/activemodel/test/cases/validations/numericality_validation_test.rb
+++ b/activemodel/test/cases/validations/numericality_validation_test.rb
@@ -237,13 +237,13 @@ class NumericalityValidationTest < ActiveModel::TestCase
     Topic.validates_numericality_of :approved, less_than: 4, message: "smaller than %{count}"
     topic = Topic.new("title" => "numeric test", "approved" => 10)
 
-    assert !topic.valid?
+    assert_not_predicate topic, :valid?
     assert_equal ["smaller than 4"], topic.errors[:approved]
 
     Topic.validates_numericality_of :approved, greater_than: 4, message: "greater than %{count}"
     topic = Topic.new("title" => "numeric test", "approved" => 1)
 
-    assert !topic.valid?
+    assert_not_predicate topic, :valid?
     assert_equal ["greater than 4"], topic.errors[:approved]
   end
 
@@ -252,12 +252,12 @@ class NumericalityValidationTest < ActiveModel::TestCase
 
     p = Person.new
     p.karma = "Pix"
-    assert p.invalid?
+    assert_predicate p, :invalid?
 
     assert_equal ["is not a number"], p.errors[:karma]
 
     p.karma = "1234"
-    assert p.valid?
+    assert_predicate p, :valid?
   ensure
     Person.clear_validators!
   end
@@ -268,7 +268,7 @@ class NumericalityValidationTest < ActiveModel::TestCase
     topic = Topic.new
     topic.approved = (base + 1).to_s
 
-    assert topic.invalid?
+    assert_predicate topic, :invalid?
   end
 
   def test_validates_numericality_with_invalid_args
diff --git a/activemodel/test/cases/validations/presence_validation_test.rb b/activemodel/test/cases/validations/presence_validation_test.rb
index 22c2f0af87..c3eca41070 100644
--- a/activemodel/test/cases/validations/presence_validation_test.rb
+++ b/activemodel/test/cases/validations/presence_validation_test.rb
@@ -17,25 +17,25 @@ class PresenceValidationTest < ActiveModel::TestCase
     Topic.validates_presence_of(:title, :content)
 
     t = Topic.new
-    assert t.invalid?
+    assert_predicate t, :invalid?
     assert_equal ["can't be blank"], t.errors[:title]
     assert_equal ["can't be blank"], t.errors[:content]
 
     t.title = "something"
     t.content = "   "
 
-    assert t.invalid?
+    assert_predicate t, :invalid?
     assert_equal ["can't be blank"], t.errors[:content]
 
     t.content = "like stuff"
 
-    assert t.valid?
+    assert_predicate t, :valid?
   end
 
   def test_accepts_array_arguments
     Topic.validates_presence_of %w(title content)
     t = Topic.new
-    assert t.invalid?
+    assert_predicate t, :invalid?
     assert_equal ["can't be blank"], t.errors[:title]
     assert_equal ["can't be blank"], t.errors[:content]
   end
@@ -43,7 +43,7 @@ class PresenceValidationTest < ActiveModel::TestCase
   def test_validates_acceptance_of_with_custom_error_using_quotes
     Person.validates_presence_of :karma, message: "This string contains 'single' and \"double\" quotes"
     p = Person.new
-    assert p.invalid?
+    assert_predicate p, :invalid?
     assert_equal "This string contains 'single' and \"double\" quotes", p.errors[:karma].last
   end
 
@@ -51,24 +51,24 @@ class PresenceValidationTest < ActiveModel::TestCase
     Person.validates_presence_of :karma
 
     p = Person.new
-    assert p.invalid?
+    assert_predicate p, :invalid?
 
     assert_equal ["can't be blank"], p.errors[:karma]
 
     p.karma = "Cold"
-    assert p.valid?
+    assert_predicate p, :valid?
   end
 
   def test_validates_presence_of_for_ruby_class_with_custom_reader
     CustomReader.validates_presence_of :karma
 
     p = CustomReader.new
-    assert p.invalid?
+    assert_predicate p, :invalid?
 
     assert_equal ["can't be blank"], p.errors[:karma]
 
     p[:karma] = "Cold"
-    assert p.valid?
+    assert_predicate p, :valid?
   end
 
   def test_validates_presence_of_with_allow_nil_option
@@ -78,7 +78,7 @@ class PresenceValidationTest < ActiveModel::TestCase
     assert t.valid?, t.errors.full_messages
 
     t.title = ""
-    assert t.invalid?
+    assert_predicate t, :invalid?
     assert_equal ["can't be blank"], t.errors[:title]
 
     t.title = "  "
diff --git a/activemodel/test/cases/validations/validates_test.rb b/activemodel/test/cases/validations/validates_test.rb
index 7f32f5dc74..80c347703a 100644
--- a/activemodel/test/cases/validations/validates_test.rb
+++ b/activemodel/test/cases/validations/validates_test.rb
@@ -37,7 +37,7 @@ class ValidatesTest < ActiveModel::TestCase
 
     person = Person.new
     person.title = 123
-    assert person.valid?
+    assert_predicate person, :valid?
   end
 
   def test_validates_with_built_in_validation_and_options
@@ -71,7 +71,7 @@ class ValidatesTest < ActiveModel::TestCase
   def test_validates_with_if_as_shared_conditions
     Person.validates :karma, presence: true, email: true, if: :condition_is_false
     person = Person.new
-    assert person.valid?
+    assert_predicate person, :valid?
   end
 
   def test_validates_with_unless_as_local_conditions
@@ -84,40 +84,40 @@ class ValidatesTest < ActiveModel::TestCase
   def test_validates_with_unless_shared_conditions
     Person.validates :karma, presence: true, email: true, unless: :condition_is_true
     person = Person.new
-    assert person.valid?
+    assert_predicate person, :valid?
   end
 
   def test_validates_with_allow_nil_shared_conditions
     Person.validates :karma, length: { minimum: 20 }, email: true, allow_nil: true
     person = Person.new
-    assert person.valid?
+    assert_predicate person, :valid?
   end
 
   def test_validates_with_regexp
     Person.validates :karma, format: /positive|negative/
     person = Person.new
-    assert person.invalid?
+    assert_predicate person, :invalid?
     assert_equal ["is invalid"], person.errors[:karma]
     person.karma = "positive"
-    assert person.valid?
+    assert_predicate person, :valid?
   end
 
   def test_validates_with_array
     Person.validates :gender, inclusion: %w(m f)
     person = Person.new
-    assert person.invalid?
+    assert_predicate person, :invalid?
     assert_equal ["is not included in the list"], person.errors[:gender]
     person.gender = "m"
-    assert person.valid?
+    assert_predicate person, :valid?
   end
 
   def test_validates_with_range
     Person.validates :karma, length: 6..20
     person = Person.new
-    assert person.invalid?
+    assert_predicate person, :invalid?
     assert_equal ["is too short (minimum is 6 characters)"], person.errors[:karma]
     person.karma = "something"
-    assert person.valid?
+    assert_predicate person, :valid?
   end
 
   def test_validates_with_validator_class_and_options
@@ -159,7 +159,7 @@ class ValidatesTest < ActiveModel::TestCase
     topic = Topic.new
     topic.title = "What's happening"
     topic.title_confirmation = "Not this"
-    assert !topic.valid?
+    assert_not_predicate topic, :valid?
     assert_equal ["Y U NO CONFIRM"], topic.errors[:title_confirmation]
   end
 end
diff --git a/activemodel/test/cases/validations/with_validation_test.rb b/activemodel/test/cases/validations/with_validation_test.rb
index 13ef5e6a31..8239792c79 100644
--- a/activemodel/test/cases/validations/with_validation_test.rb
+++ b/activemodel/test/cases/validations/with_validation_test.rb
@@ -65,7 +65,7 @@ class ValidatesWithTest < ActiveModel::TestCase
   test "with multiple classes" do
     Topic.validates_with(ValidatorThatAddsErrors, OtherValidatorThatAddsErrors)
     topic = Topic.new
-    assert topic.invalid?
+    assert_predicate topic, :invalid?
     assert_includes topic.errors[:base], ERROR_MESSAGE
     assert_includes topic.errors[:base], OTHER_ERROR_MESSAGE
   end
@@ -79,21 +79,21 @@ class ValidatesWithTest < ActiveModel::TestCase
     validator.expect(:is_a?, false, [String])
 
     Topic.validates_with(validator, if: :condition_is_true, foo: :bar)
-    assert topic.valid?
+    assert_predicate topic, :valid?
     validator.verify
   end
 
   test "validates_with with options" do
     Topic.validates_with(ValidatorThatValidatesOptions, field: :first_name)
     topic = Topic.new
-    assert topic.invalid?
+    assert_predicate topic, :invalid?
     assert_includes topic.errors[:base], ERROR_MESSAGE
   end
 
   test "validates_with each validator" do
     Topic.validates_with(ValidatorPerEachAttribute, attributes: [:title, :content])
     topic = Topic.new title: "Title", content: "Content"
-    assert topic.invalid?
+    assert_predicate topic, :invalid?
     assert_equal ["Value is Title"], topic.errors[:title]
     assert_equal ["Value is Content"], topic.errors[:content]
   end
@@ -113,28 +113,28 @@ class ValidatesWithTest < ActiveModel::TestCase
   test "each validator skip nil values if :allow_nil is set to true" do
     Topic.validates_with(ValidatorPerEachAttribute, attributes: [:title, :content], allow_nil: true)
     topic = Topic.new content: ""
-    assert topic.invalid?
-    assert topic.errors[:title].empty?
+    assert_predicate topic, :invalid?
+    assert_empty topic.errors[:title]
     assert_equal ["Value is "], topic.errors[:content]
   end
 
   test "each validator skip blank values if :allow_blank is set to true" do
     Topic.validates_with(ValidatorPerEachAttribute, attributes: [:title, :content], allow_blank: true)
     topic = Topic.new content: ""
-    assert topic.valid?
-    assert topic.errors[:title].empty?
-    assert topic.errors[:content].empty?
+    assert_predicate topic, :valid?
+    assert_empty topic.errors[:title]
+    assert_empty topic.errors[:content]
   end
 
   test "validates_with can validate with an instance method" do
     Topic.validates :title, with: :my_validation
 
     topic = Topic.new title: "foo"
-    assert topic.valid?
-    assert topic.errors[:title].empty?
+    assert_predicate topic, :valid?
+    assert_empty topic.errors[:title]
 
     topic = Topic.new
-    assert !topic.valid?
+    assert_not_predicate topic, :valid?
     assert_equal ["is missing"], topic.errors[:title]
   end
 
@@ -142,8 +142,8 @@ class ValidatesWithTest < ActiveModel::TestCase
     Topic.validates :title, :content, with: :my_validation_with_arg
 
     topic = Topic.new title: "foo"
-    assert !topic.valid?
-    assert topic.errors[:title].empty?
+    assert_not_predicate topic, :valid?
+    assert_empty topic.errors[:title]
     assert_equal ["is missing"], topic.errors[:content]
   end
 end
diff --git a/activemodel/test/cases/validations_test.rb b/activemodel/test/cases/validations_test.rb
index ab8c41bbd0..7776233db5 100644
--- a/activemodel/test/cases/validations_test.rb
+++ b/activemodel/test/cases/validations_test.rb
@@ -30,7 +30,7 @@ class ValidationsTest < ActiveModel::TestCase
   def test_single_attr_validation_and_error_msg
     r = Reply.new
     r.title = "There's no content!"
-    assert r.invalid?
+    assert_predicate r, :invalid?
     assert r.errors[:content].any?, "A reply without content should mark that attribute as invalid"
     assert_equal ["is Empty"], r.errors["content"], "A reply without content should contain an error"
     assert_equal 1, r.errors.count
@@ -38,7 +38,7 @@ class ValidationsTest < ActiveModel::TestCase
 
   def test_double_attr_validation_and_error_msg
     r = Reply.new
-    assert r.invalid?
+    assert_predicate r, :invalid?
 
     assert r.errors[:title].any?, "A reply without title should mark that attribute as invalid"
     assert_equal ["is Empty"], r.errors["title"], "A reply without title should contain an error"
@@ -111,8 +111,8 @@ class ValidationsTest < ActiveModel::TestCase
 
   def test_errors_empty_after_errors_on_check
     t = Topic.new
-    assert t.errors[:id].empty?
-    assert t.errors.empty?
+    assert_empty t.errors[:id]
+    assert_empty t.errors
   end
 
   def test_validates_each
@@ -122,7 +122,7 @@ class ValidationsTest < ActiveModel::TestCase
       hits += 1
     end
     t = Topic.new("title" => "valid", "content" => "whatever")
-    assert t.invalid?
+    assert_predicate t, :invalid?
     assert_equal 4, hits
     assert_equal %w(gotcha gotcha), t.errors[:title]
     assert_equal %w(gotcha gotcha), t.errors[:content]
@@ -135,7 +135,7 @@ class ValidationsTest < ActiveModel::TestCase
       hits += 1
     end
     t = CustomReader.new("title" => "valid", "content" => "whatever")
-    assert t.invalid?
+    assert_predicate t, :invalid?
     assert_equal 4, hits
     assert_equal %w(gotcha gotcha), t.errors[:title]
     assert_equal %w(gotcha gotcha), t.errors[:content]
@@ -146,16 +146,16 @@ class ValidationsTest < ActiveModel::TestCase
   def test_validate_block
     Topic.validate { errors.add("title", "will never be valid") }
     t = Topic.new("title" => "Title", "content" => "whatever")
-    assert t.invalid?
-    assert t.errors[:title].any?
+    assert_predicate t, :invalid?
+    assert_predicate t.errors[:title], :any?
     assert_equal ["will never be valid"], t.errors["title"]
   end
 
   def test_validate_block_with_params
     Topic.validate { |topic| topic.errors.add("title", "will never be valid") }
     t = Topic.new("title" => "Title", "content" => "whatever")
-    assert t.invalid?
-    assert t.errors[:title].any?
+    assert_predicate t, :invalid?
+    assert_predicate t.errors[:title], :any?
     assert_equal ["will never be valid"], t.errors["title"]
   end
 
@@ -214,7 +214,7 @@ class ValidationsTest < ActiveModel::TestCase
   def test_errors_conversions
     Topic.validates_presence_of %w(title content)
     t = Topic.new
-    assert t.invalid?
+    assert_predicate t, :invalid?
 
     xml = t.errors.to_xml
     assert_match %r{<errors>}, xml
@@ -232,14 +232,14 @@ class ValidationsTest < ActiveModel::TestCase
     Topic.validates_length_of :title, minimum: 2
 
     t = Topic.new("title" => "")
-    assert t.invalid?
+    assert_predicate t, :invalid?
     assert_equal "can't be blank", t.errors["title"].first
     Topic.validates_presence_of :title, :author_name
     Topic.validate { errors.add("author_email_address", "will never be valid") }
     Topic.validates_length_of :title, :content, minimum: 2
 
     t = Topic.new title: ""
-    assert t.invalid?
+    assert_predicate t, :invalid?
 
     assert_equal :title, key = t.errors.keys[0]
     assert_equal "can't be blank", t.errors[key][0]
@@ -258,8 +258,8 @@ class ValidationsTest < ActiveModel::TestCase
     t = Topic.new(title: "")
 
     # If block should not fire
-    assert t.valid?
-    assert t.author_name.nil?
+    assert_predicate t, :valid?
+    assert_predicate t.author_name, :nil?
 
     # If block should fire
     assert t.invalid?(:update)
@@ -270,18 +270,18 @@ class ValidationsTest < ActiveModel::TestCase
     Topic.validates_presence_of :title
 
     t = Topic.new
-    assert t.invalid?
-    assert t.errors[:title].any?
+    assert_predicate t, :invalid?
+    assert_predicate t.errors[:title], :any?
 
     t.title = "Things are going to change"
-    assert !t.invalid?
+    assert_not_predicate t, :invalid?
   end
 
   def test_validation_with_message_as_proc
     Topic.validates_presence_of(:title, message: proc { "no blanks here".upcase })
 
     t = Topic.new
-    assert t.invalid?
+    assert_predicate t, :invalid?
     assert_equal ["NO BLANKS HERE"], t.errors[:title]
   end
 
@@ -331,13 +331,13 @@ class ValidationsTest < ActiveModel::TestCase
     Topic.validates :content, length: { minimum: 10 }
 
     topic = Topic.new
-    assert topic.invalid?
+    assert_predicate topic, :invalid?
     assert_equal 3, topic.errors.size
 
     topic.title = "Some Title"
     topic.author_name = "Some Author"
     topic.content = "Some Content Whose Length is more than 10."
-    assert topic.valid?
+    assert_predicate topic, :valid?
   end
 
   def test_validate
@@ -381,7 +381,7 @@ class ValidationsTest < ActiveModel::TestCase
 
   def test_strict_validation_not_fails
     Topic.validates :title, strict: true, presence: true
-    assert Topic.new(title: "hello").valid?
+    assert_predicate Topic.new(title: "hello"), :valid?
   end
 
   def test_strict_validation_particular_validator
@@ -414,7 +414,7 @@ class ValidationsTest < ActiveModel::TestCase
 
   def test_validates_with_false_hash_value
     Topic.validates :title, presence: false
-    assert Topic.new.valid?
+    assert_predicate Topic.new, :valid?
   end
 
   def test_strict_validation_error_message
@@ -439,19 +439,19 @@ class ValidationsTest < ActiveModel::TestCase
 
     duped = topic.dup
     duped.title = nil
-    assert duped.invalid?
+    assert_predicate duped, :invalid?
 
     topic.title = nil
     duped.title = "Mathematics"
-    assert topic.invalid?
-    assert duped.valid?
+    assert_predicate topic, :invalid?
+    assert_predicate duped, :valid?
   end
 
   def test_validation_with_message_as_proc_that_takes_a_record_as_a_parameter
     Topic.validates_presence_of(:title, message: proc { |record| "You have failed me for the last time, #{record.author_name}." })
 
     t = Topic.new(author_name: "Admiral")
-    assert t.invalid?
+    assert_predicate t, :invalid?
     assert_equal ["You have failed me for the last time, Admiral."], t.errors[:title]
   end
 
@@ -459,7 +459,7 @@ class ValidationsTest < ActiveModel::TestCase
     Topic.validates_presence_of(:title, message: proc { |record, data| "#{data[:attribute]} is missing. You have failed me for the last time, #{record.author_name}." })
 
     t = Topic.new(author_name: "Admiral")
-    assert t.invalid?
+    assert_predicate t, :invalid?
     assert_equal ["Title is missing. You have failed me for the last time, Admiral."], t.errors[:title]
   end
 end