Fix `CustomCops/AssertNot` to allow it to have failure message

Follow up of #32605.

45 files changed, 143 insertions, 143 deletions

diff --git a/actionpack/test/controller/parameters/nested_parameters_permit_test.rb b/actionpack/test/controller/parameters/nested_parameters_permit_test.rb
index ccc6bf9807..1403e224c0 100644
--- a/actionpack/test/controller/parameters/nested_parameters_permit_test.rb
+++ b/actionpack/test/controller/parameters/nested_parameters_permit_test.rb
@@ -5,7 +5,7 @@ require "action_controller/metal/strong_parameters"
 
 class NestedParametersPermitTest < ActiveSupport::TestCase
   def assert_filtered_out(params, key)
-    assert !params.has_key?(key), "key #{key.inspect} has not been filtered out"
+    assert_not params.has_key?(key), "key #{key.inspect} has not been filtered out"
   end
 
   test "permitted nested parameters" do
diff --git a/actionpack/test/controller/parameters/parameters_permit_test.rb b/actionpack/test/controller/parameters/parameters_permit_test.rb
index 34b9ac0ab8..d2fa0aa16e 100644
--- a/actionpack/test/controller/parameters/parameters_permit_test.rb
+++ b/actionpack/test/controller/parameters/parameters_permit_test.rb
@@ -6,7 +6,7 @@ require "action_controller/metal/strong_parameters"
 
 class ParametersPermitTest < ActiveSupport::TestCase
   def assert_filtered_out(params, key)
-    assert !params.has_key?(key), "key #{key.inspect} has not been filtered out"
+    assert_not params.has_key?(key), "key #{key.inspect} has not been filtered out"
   end
 
   setup do
diff --git a/actionpack/test/controller/routing_test.rb b/actionpack/test/controller/routing_test.rb
index 259f3b8855..9d0a8b4f00 100644
--- a/actionpack/test/controller/routing_test.rb
+++ b/actionpack/test/controller/routing_test.rb
@@ -1288,14 +1288,14 @@ class RouteSetTest < ActiveSupport::TestCase
   end
 
   def test_routing_traversal_does_not_load_extra_classes
-    assert !Object.const_defined?("Profiler__"), "Profiler should not be loaded"
+    assert_not Object.const_defined?("Profiler__"), "Profiler should not be loaded"
     set.draw do
       get "/profile" => "profile#index"
     end
 
     request_path_params("/profile") rescue nil
 
-    assert !Object.const_defined?("Profiler__"), "Profiler should not be loaded"
+    assert_not Object.const_defined?("Profiler__"), "Profiler should not be loaded"
   end
 
   def test_recognize_with_conditions_and_format
diff --git a/actionpack/test/dispatch/response_test.rb b/actionpack/test/dispatch/response_test.rb
index 6d87314e97..0f37d074af 100644
--- a/actionpack/test/dispatch/response_test.rb
+++ b/actionpack/test/dispatch/response_test.rb
@@ -158,7 +158,7 @@ class ResponseTest < ActiveSupport::TestCase
       @response.status = c.to_s
       @response.set_header "Content-Length", "0"
       _, headers, _ = @response.to_a
-      assert !headers.has_key?("Content-Length"), "#{c} must not have a Content-Length header field"
+      assert_not headers.has_key?("Content-Length"), "#{c} must not have a Content-Length header field"
     end
   end
 
@@ -177,7 +177,7 @@ class ResponseTest < ActiveSupport::TestCase
       @response = ActionDispatch::Response.new
       @response.status = c.to_s
       _, headers, _ = @response.to_a
-      assert !headers.has_key?("Content-Type"), "#{c} should not have Content-Type header"
+      assert_not headers.has_key?("Content-Type"), "#{c} should not have Content-Type header"
     end
 
     [200, 302, 404, 500].each do |c|
diff --git a/actionpack/test/dispatch/routing_test.rb b/actionpack/test/dispatch/routing_test.rb
index dd6adcbfd1..5efbe5b553 100644
--- a/actionpack/test/dispatch/routing_test.rb
+++ b/actionpack/test/dispatch/routing_test.rb
@@ -3153,7 +3153,7 @@ class TestRoutingMapper < ActionDispatch::IntegrationTest
       after = has_named_route?(:hello)
     end
 
-    assert !before, "expected to not have named route :hello before route definition"
+    assert_not before, "expected to not have named route :hello before route definition"
     assert after, "expected to have named route :hello after route definition"
   end
 
diff --git a/actionview/test/template/partial_iteration_test.rb b/actionview/test/template/partial_iteration_test.rb
index 06bbdabac0..1c3c566667 100644
--- a/actionview/test/template/partial_iteration_test.rb
+++ b/actionview/test/template/partial_iteration_test.rb
@@ -18,7 +18,7 @@ class PartialIterationTest < ActiveSupport::TestCase
   def test_first_is_false_unless_current_is_at_the_first_index
     iteration = ActionView::PartialIteration.new 3
     iteration.iterate!
-    assert !iteration.first?, "not first when current is 1"
+    assert_not iteration.first?, "not first when current is 1"
   end
 
   def test_last_is_true_when_current_is_at_the_last_index
@@ -30,6 +30,6 @@ class PartialIterationTest < ActiveSupport::TestCase
 
   def test_last_is_false_unless_current_is_at_the_last_index
     iteration = ActionView::PartialIteration.new 3
-    assert !iteration.last?, "not last when current is 0"
+    assert_not iteration.last?, "not last when current is 0"
   end
 end
diff --git a/activemodel/test/cases/naming_test.rb b/activemodel/test/cases/naming_test.rb
index 009f1f47af..4693da434c 100644
--- a/activemodel/test/cases/naming_test.rb
+++ b/activemodel/test/cases/naming_test.rb
@@ -248,7 +248,7 @@ class NamingHelpersTest < ActiveModel::TestCase
 
   def test_uncountable
     assert uncountable?(@uncountable), "Expected 'sheep' to be uncountable"
-    assert !uncountable?(@klass), "Expected 'contact' to be countable"
+    assert_not uncountable?(@klass), "Expected 'contact' to be countable"
   end
 
   def test_uncountable_route_key
diff --git a/activemodel/test/cases/secure_password_test.rb b/activemodel/test/cases/secure_password_test.rb
index 912cb6d5ab..c347aa9b24 100644
--- a/activemodel/test/cases/secure_password_test.rb
+++ b/activemodel/test/cases/secure_password_test.rb
@@ -49,14 +49,14 @@ class SecurePasswordTest < ActiveModel::TestCase
 
   test "create a new user with validation and a blank password" do
     @user.password = ""
-    assert !@user.valid?(:create), "user should be invalid"
+    assert_not @user.valid?(:create), "user should be invalid"
     assert_equal 1, @user.errors.count
     assert_equal ["can't be blank"], @user.errors[:password]
   end
 
   test "create a new user with validation and a nil password" do
     @user.password = nil
-    assert !@user.valid?(:create), "user should be invalid"
+    assert_not @user.valid?(:create), "user should be invalid"
     assert_equal 1, @user.errors.count
     assert_equal ["can't be blank"], @user.errors[:password]
   end
@@ -64,7 +64,7 @@ class SecurePasswordTest < ActiveModel::TestCase
   test "create a new user with validation and password length greater than 72" do
     @user.password = "a" * 73
     @user.password_confirmation = "a" * 73
-    assert !@user.valid?(:create), "user should be invalid"
+    assert_not @user.valid?(:create), "user should be invalid"
     assert_equal 1, @user.errors.count
     assert_equal ["is too long (maximum is 72 characters)"], @user.errors[:password]
   end
@@ -72,7 +72,7 @@ class SecurePasswordTest < ActiveModel::TestCase
   test "create a new user with validation and a blank password confirmation" do
     @user.password = "password"
     @user.password_confirmation = ""
-    assert !@user.valid?(:create), "user should be invalid"
+    assert_not @user.valid?(:create), "user should be invalid"
     assert_equal 1, @user.errors.count
     assert_equal ["doesn't match Password"], @user.errors[:password_confirmation]
   end
@@ -86,7 +86,7 @@ class SecurePasswordTest < ActiveModel::TestCase
   test "create a new user with validation and an incorrect password confirmation" do
     @user.password = "password"
     @user.password_confirmation = "something else"
-    assert !@user.valid?(:create), "user should be invalid"
+    assert_not @user.valid?(:create), "user should be invalid"
     assert_equal 1, @user.errors.count
     assert_equal ["doesn't match Password"], @user.errors[:password_confirmation]
   end
@@ -125,7 +125,7 @@ class SecurePasswordTest < ActiveModel::TestCase
 
   test "updating an existing user with validation and a nil password" do
     @existing_user.password = nil
-    assert !@existing_user.valid?(:update), "user should be invalid"
+    assert_not @existing_user.valid?(:update), "user should be invalid"
     assert_equal 1, @existing_user.errors.count
     assert_equal ["can't be blank"], @existing_user.errors[:password]
   end
@@ -133,7 +133,7 @@ class SecurePasswordTest < ActiveModel::TestCase
   test "updating an existing user with validation and password length greater than 72" do
     @existing_user.password = "a" * 73
     @existing_user.password_confirmation = "a" * 73
-    assert !@existing_user.valid?(:update), "user should be invalid"
+    assert_not @existing_user.valid?(:update), "user should be invalid"
     assert_equal 1, @existing_user.errors.count
     assert_equal ["is too long (maximum is 72 characters)"], @existing_user.errors[:password]
   end
@@ -141,7 +141,7 @@ class SecurePasswordTest < ActiveModel::TestCase
   test "updating an existing user with validation and a blank password confirmation" do
     @existing_user.password = "password"
     @existing_user.password_confirmation = ""
-    assert !@existing_user.valid?(:update), "user should be invalid"
+    assert_not @existing_user.valid?(:update), "user should be invalid"
     assert_equal 1, @existing_user.errors.count
     assert_equal ["doesn't match Password"], @existing_user.errors[:password_confirmation]
   end
@@ -155,21 +155,21 @@ class SecurePasswordTest < ActiveModel::TestCase
   test "updating an existing user with validation and an incorrect password confirmation" do
     @existing_user.password = "password"
     @existing_user.password_confirmation = "something else"
-    assert !@existing_user.valid?(:update), "user should be invalid"
+    assert_not @existing_user.valid?(:update), "user should be invalid"
     assert_equal 1, @existing_user.errors.count
     assert_equal ["doesn't match Password"], @existing_user.errors[:password_confirmation]
   end
 
   test "updating an existing user with validation and a blank password digest" do
     @existing_user.password_digest = ""
-    assert !@existing_user.valid?(:update), "user should be invalid"
+    assert_not @existing_user.valid?(:update), "user should be invalid"
     assert_equal 1, @existing_user.errors.count
     assert_equal ["can't be blank"], @existing_user.errors[:password]
   end
 
   test "updating an existing user with validation and a nil password digest" do
     @existing_user.password_digest = nil
-    assert !@existing_user.valid?(:update), "user should be invalid"
+    assert_not @existing_user.valid?(:update), "user should be invalid"
     assert_equal 1, @existing_user.errors.count
     assert_equal ["can't be blank"], @existing_user.errors[:password]
   end
diff --git a/activemodel/test/cases/validations/validates_test.rb b/activemodel/test/cases/validations/validates_test.rb
index 80c347703a..ae5a875c24 100644
--- a/activemodel/test/cases/validations/validates_test.rb
+++ b/activemodel/test/cases/validations/validates_test.rb
@@ -19,7 +19,7 @@ class ValidatesTest < ActiveModel::TestCase
   def test_validates_with_messages_empty
     Person.validates :title, presence: { message: "" }
     person = Person.new
-    assert !person.valid?, "person should not be valid."
+    assert_not person.valid?, "person should not be valid."
   end
 
   def test_validates_with_built_in_validation
diff --git a/activerecord/test/cases/adapters/mysql2/schema_test.rb b/activerecord/test/cases/adapters/mysql2/schema_test.rb
index b587e756cf..1283b0642c 100644
--- a/activerecord/test/cases/adapters/mysql2/schema_test.rb
+++ b/activerecord/test/cases/adapters/mysql2/schema_test.rb
@@ -67,7 +67,7 @@ module ActiveRecord
       end
 
       def test_data_source_exists_wrong_schema
-        assert(!@connection.data_source_exists?("#{@db_name}.zomg"), "data_source should not exist")
+        assert_not(@connection.data_source_exists?("#{@db_name}.zomg"), "data_source should not exist")
       end
 
       def test_dump_indexes
diff --git a/activerecord/test/cases/adapters/postgresql/array_test.rb b/activerecord/test/cases/adapters/postgresql/array_test.rb
index 58fa7532a2..42618c2ec3 100644
--- a/activerecord/test/cases/adapters/postgresql/array_test.rb
+++ b/activerecord/test/cases/adapters/postgresql/array_test.rb
@@ -353,7 +353,7 @@ class PostgresqlArrayTest < ActiveRecord::PostgreSQLTestCase
     assert e1.persisted?, "Saving e1"
 
     e2 = klass.create("tags" => ["black", "blue"])
-    assert !e2.persisted?, "e2 shouldn't be valid"
+    assert_not e2.persisted?, "e2 shouldn't be valid"
     assert e2.errors[:tags].any?, "Should have errors for tags"
     assert_equal ["has already been taken"], e2.errors[:tags], "Should have uniqueness message for tags"
   end
diff --git a/activerecord/test/cases/adapters/postgresql/schema_test.rb b/activerecord/test/cases/adapters/postgresql/schema_test.rb
index 7ad03c194f..a36d066c80 100644
--- a/activerecord/test/cases/adapters/postgresql/schema_test.rb
+++ b/activerecord/test/cases/adapters/postgresql/schema_test.rb
@@ -204,12 +204,12 @@ class SchemaTest < ActiveRecord::PostgreSQLTestCase
 
   def test_data_source_exists_when_not_on_schema_search_path
     with_schema_search_path("PUBLIC") do
-      assert(!@connection.data_source_exists?(TABLE_NAME), "data_source exists but should not be found")
+      assert_not(@connection.data_source_exists?(TABLE_NAME), "data_source exists but should not be found")
     end
   end
 
   def test_data_source_exists_wrong_schema
-    assert(!@connection.data_source_exists?("foo.things"), "data_source should not exist")
+    assert_not(@connection.data_source_exists?("foo.things"), "data_source should not exist")
   end
 
   def test_data_source_exists_quoted_names
diff --git a/activerecord/test/cases/adapters/sqlite3/sqlite3_adapter_test.rb b/activerecord/test/cases/adapters/sqlite3/sqlite3_adapter_test.rb
index 7e0ce3a28e..ad155c7492 100644
--- a/activerecord/test/cases/adapters/sqlite3/sqlite3_adapter_test.rb
+++ b/activerecord/test/cases/adapters/sqlite3/sqlite3_adapter_test.rb
@@ -61,7 +61,7 @@ module ActiveRecord
           WHERE  #{Owner.primary_key} = #{owner.id}
         esql
 
-        assert(!result.rows.first.include?("blob"), "should not store blobs")
+        assert_not(result.rows.first.include?("blob"), "should not store blobs")
       ensure
         owner.delete
       end
diff --git a/activerecord/test/cases/associations/has_many_associations_test.rb b/activerecord/test/cases/associations/has_many_associations_test.rb
index bf2e051def..cc8f33f142 100644
--- a/activerecord/test/cases/associations/has_many_associations_test.rb
+++ b/activerecord/test/cases/associations/has_many_associations_test.rb
@@ -1574,7 +1574,7 @@ class HasManyAssociationsTest < ActiveRecord::TestCase
     assert_predicate companies(:first_firm).clients_of_firm, :loaded?
 
     clients = companies(:first_firm).clients_of_firm.to_a
-    assert !clients.empty?, "37signals has clients after load"
+    assert_not clients.empty?, "37signals has clients after load"
     destroyed = companies(:first_firm).clients_of_firm.destroy_all
     assert_equal clients.sort_by(&:id), destroyed.sort_by(&:id)
     assert destroyed.all?(&:frozen?), "destroyed clients should be frozen"
diff --git a/activerecord/test/cases/associations/inner_join_association_test.rb b/activerecord/test/cases/associations/inner_join_association_test.rb
index ca0620dc3b..c33dcdee61 100644
--- a/activerecord/test/cases/associations/inner_join_association_test.rb
+++ b/activerecord/test/cases/associations/inner_join_association_test.rb
@@ -79,19 +79,19 @@ class InnerJoinAssociationTest < ActiveRecord::TestCase
 
   def test_find_with_implicit_inner_joins_honors_readonly_with_select
     authors = Author.joins(:posts).select("authors.*").to_a
-    assert !authors.empty?, "expected authors to be non-empty"
+    assert_not authors.empty?, "expected authors to be non-empty"
     assert authors.all? { |a| !a.readonly? }, "expected no authors to be readonly"
   end
 
   def test_find_with_implicit_inner_joins_honors_readonly_false
     authors = Author.joins(:posts).readonly(false).to_a
-    assert !authors.empty?, "expected authors to be non-empty"
+    assert_not authors.empty?, "expected authors to be non-empty"
     assert authors.all? { |a| !a.readonly? }, "expected no authors to be readonly"
   end
 
   def test_find_with_implicit_inner_joins_does_not_set_associations
     authors = Author.joins(:posts).select("authors.*").to_a
-    assert !authors.empty?, "expected authors to be non-empty"
+    assert_not authors.empty?, "expected authors to be non-empty"
     assert authors.all? { |a| !a.instance_variable_defined?(:@posts) }, "expected no authors to have the @posts association loaded"
   end
 
diff --git a/activerecord/test/cases/associations/inverse_associations_test.rb b/activerecord/test/cases/associations/inverse_associations_test.rb
index 896bf574f4..da3a42e2b5 100644
--- a/activerecord/test/cases/associations/inverse_associations_test.rb
+++ b/activerecord/test/cases/associations/inverse_associations_test.rb
@@ -119,11 +119,11 @@ class AutomaticInverseFindingTests < ActiveRecord::TestCase
   def test_polymorphic_and_has_many_through_relationships_should_not_have_inverses
     sponsor_reflection = Sponsor.reflect_on_association(:sponsorable)
 
-    assert !sponsor_reflection.has_inverse?, "A polymorphic association should not find an inverse automatically"
+    assert_not sponsor_reflection.has_inverse?, "A polymorphic association should not find an inverse automatically"
 
     club_reflection = Club.reflect_on_association(:members)
 
-    assert !club_reflection.has_inverse?, "A has_many_through association should not find an inverse automatically"
+    assert_not club_reflection.has_inverse?, "A has_many_through association should not find an inverse automatically"
   end
 
   def test_polymorphic_has_one_should_find_inverse_automatically
diff --git a/activerecord/test/cases/associations_test.rb b/activerecord/test/cases/associations_test.rb
index fce2a7eed1..739eb02e0c 100644
--- a/activerecord/test/cases/associations_test.rb
+++ b/activerecord/test/cases/associations_test.rb
@@ -92,7 +92,7 @@ class AssociationsTest < ActiveRecord::TestCase
 
     firm.clients.reload
 
-    assert !firm.clients.empty?, "New firm should have reloaded client objects"
+    assert_not firm.clients.empty?, "New firm should have reloaded client objects"
     assert_equal 1, firm.clients.size, "New firm should have reloaded clients count"
   end
 
@@ -102,8 +102,8 @@ class AssociationsTest < ActiveRecord::TestCase
     has_many_reflections = [Tag.reflect_on_association(:taggings), Developer.reflect_on_association(:projects)]
     mixed_reflections = (belongs_to_reflections + has_many_reflections).uniq
     assert using_limitable_reflections.call(belongs_to_reflections), "Belong to associations are limitable"
-    assert !using_limitable_reflections.call(has_many_reflections), "All has many style associations are not limitable"
-    assert !using_limitable_reflections.call(mixed_reflections), "No collection associations (has many style) should pass"
+    assert_not using_limitable_reflections.call(has_many_reflections), "All has many style associations are not limitable"
+    assert_not using_limitable_reflections.call(mixed_reflections), "No collection associations (has many style) should pass"
   end
 
   def test_association_with_references
diff --git a/activerecord/test/cases/attribute_methods_test.rb b/activerecord/test/cases/attribute_methods_test.rb
index 1a37ad963f..4a7427158a 100644
--- a/activerecord/test/cases/attribute_methods_test.rb
+++ b/activerecord/test/cases/attribute_methods_test.rb
@@ -354,9 +354,9 @@ class AttributeMethodsTest < ActiveRecord::TestCase
   test "read_attribute when false" do
     topic = topics(:first)
     topic.approved = false
-    assert !topic.approved?, "approved should be false"
+    assert_not topic.approved?, "approved should be false"
     topic.approved = "false"
-    assert !topic.approved?, "approved should be false"
+    assert_not topic.approved?, "approved should be false"
   end
 
   test "read_attribute when true" do
@@ -370,10 +370,10 @@ class AttributeMethodsTest < ActiveRecord::TestCase
   test "boolean attributes writing and reading" do
     topic = Topic.new
     topic.approved = "false"
-    assert !topic.approved?, "approved should be false"
+    assert_not topic.approved?, "approved should be false"
 
     topic.approved = "false"
-    assert !topic.approved?, "approved should be false"
+    assert_not topic.approved?, "approved should be false"
 
     topic.approved = "true"
     assert topic.approved?, "approved should be true"
diff --git a/activerecord/test/cases/clone_test.rb b/activerecord/test/cases/clone_test.rb
index 65e5016040..eea36ee736 100644
--- a/activerecord/test/cases/clone_test.rb
+++ b/activerecord/test/cases/clone_test.rb
@@ -12,7 +12,7 @@ module ActiveRecord
       cloned = topic.clone
       assert topic.persisted?, "topic persisted"
       assert cloned.persisted?, "topic persisted"
-      assert !cloned.new_record?, "topic is not new"
+      assert_not cloned.new_record?, "topic is not new"
     end
 
     def test_stays_frozen
@@ -21,7 +21,7 @@ module ActiveRecord
 
       cloned = topic.clone
       assert cloned.persisted?, "topic persisted"
-      assert !cloned.new_record?, "topic is not new"
+      assert_not cloned.new_record?, "topic is not new"
       assert cloned.frozen?, "topic should be frozen"
     end
 
diff --git a/activerecord/test/cases/defaults_test.rb b/activerecord/test/cases/defaults_test.rb
index 3d11b573f1..1c96aaabe2 100644
--- a/activerecord/test/cases/defaults_test.rb
+++ b/activerecord/test/cases/defaults_test.rb
@@ -9,7 +9,7 @@ class DefaultTest < ActiveRecord::TestCase
   def test_nil_defaults_for_not_null_columns
     %w(id name course_id).each do |name|
       column = Entrant.columns_hash[name]
-      assert !column.null, "#{name} column should be NOT NULL"
+      assert_not column.null, "#{name} column should be NOT NULL"
       assert_not column.default, "#{name} column should be DEFAULT 'nil'"
     end
   end
diff --git a/activerecord/test/cases/dup_test.rb b/activerecord/test/cases/dup_test.rb
index 387a0b1fdd..a2efbf89f9 100644
--- a/activerecord/test/cases/dup_test.rb
+++ b/activerecord/test/cases/dup_test.rb
@@ -17,7 +17,7 @@ module ActiveRecord
       topic = Topic.first
 
       duped = topic.dup
-      assert !duped.readonly?, "should not be readonly"
+      assert_not duped.readonly?, "should not be readonly"
     end
 
     def test_is_readonly
@@ -32,7 +32,7 @@ module ActiveRecord
       topic = Topic.first
       duped = topic.dup
 
-      assert !duped.persisted?, "topic not persisted"
+      assert_not duped.persisted?, "topic not persisted"
       assert duped.new_record?, "topic is new"
     end
 
@@ -140,7 +140,7 @@ module ActiveRecord
       prev_default_scopes = Topic.default_scopes
       Topic.default_scopes = [proc { Topic.where(approved: true) }]
       topic = Topic.new(approved: false)
-      assert !topic.dup.approved?, "should not be overridden by default scopes"
+      assert_not topic.dup.approved?, "should not be overridden by default scopes"
     ensure
       Topic.default_scopes = prev_default_scopes
     end
diff --git a/activerecord/test/cases/fixtures_test.rb b/activerecord/test/cases/fixtures_test.rb
index a4fa3c285b..ee88bd8144 100644
--- a/activerecord/test/cases/fixtures_test.rb
+++ b/activerecord/test/cases/fixtures_test.rb
@@ -599,7 +599,7 @@ class FixturesWithoutInstantiationTest < ActiveRecord::TestCase
   end
 
   def test_fixtures_from_root_yml_without_instantiation
-    assert !defined?(@unknown), "@unknown is not defined"
+    assert_not defined?(@unknown), "@unknown is not defined"
   end
 
   def test_visibility_of_accessor_method
@@ -634,7 +634,7 @@ class FixturesWithoutInstanceInstantiationTest < ActiveRecord::TestCase
   fixtures :topics, :developers, :accounts
 
   def test_without_instance_instantiation
-    assert !defined?(@first), "@first is not defined"
+    assert_not defined?(@first), "@first is not defined"
   end
 end
 
diff --git a/activerecord/test/cases/inheritance_test.rb b/activerecord/test/cases/inheritance_test.rb
index 7a5c06b894..4a0ad0442a 100644
--- a/activerecord/test/cases/inheritance_test.rb
+++ b/activerecord/test/cases/inheritance_test.rb
@@ -163,7 +163,7 @@ class InheritanceTest < ActiveRecord::TestCase
     assert_not_predicate ActiveRecord::Base, :descends_from_active_record?
     assert AbstractCompany.descends_from_active_record?, "AbstractCompany should descend from ActiveRecord::Base"
     assert Company.descends_from_active_record?, "Company should descend from ActiveRecord::Base"
-    assert !Class.new(Company).descends_from_active_record?, "Company subclass should not descend from ActiveRecord::Base"
+    assert_not Class.new(Company).descends_from_active_record?, "Company subclass should not descend from ActiveRecord::Base"
   end
 
   def test_abstract_class
diff --git a/activerecord/test/cases/invertible_migration_test.rb b/activerecord/test/cases/invertible_migration_test.rb
index 9c85543b9b..363beb4780 100644
--- a/activerecord/test/cases/invertible_migration_test.rb
+++ b/activerecord/test/cases/invertible_migration_test.rb
@@ -341,7 +341,7 @@ module ActiveRecord
     def test_legacy_down
       LegacyMigration.migrate :up
       LegacyMigration.migrate :down
-      assert !ActiveRecord::Base.connection.table_exists?("horses"), "horses should not exist"
+      assert_not ActiveRecord::Base.connection.table_exists?("horses"), "horses should not exist"
     end
 
     def test_up
@@ -352,7 +352,7 @@ module ActiveRecord
     def test_down
       LegacyMigration.up
       LegacyMigration.down
-      assert !ActiveRecord::Base.connection.table_exists?("horses"), "horses should not exist"
+      assert_not ActiveRecord::Base.connection.table_exists?("horses"), "horses should not exist"
     end
 
     def test_migrate_down_with_table_name_prefix
@@ -361,7 +361,7 @@ module ActiveRecord
       migration = InvertibleMigration.new
       migration.migrate(:up)
       assert_nothing_raised { migration.migrate(:down) }
-      assert !ActiveRecord::Base.connection.table_exists?("p_horses_s"), "p_horses_s should not exist"
+      assert_not ActiveRecord::Base.connection.table_exists?("p_horses_s"), "p_horses_s should not exist"
     ensure
       ActiveRecord::Base.table_name_prefix = ActiveRecord::Base.table_name_suffix = ""
     end
@@ -383,7 +383,7 @@ module ActiveRecord
         connection = ActiveRecord::Base.connection
         assert connection.index_exists?(:horses, :content),
                "index on content should exist"
-        assert !connection.index_exists?(:horses, :content, name: "horses_index_named"),
+        assert_not connection.index_exists?(:horses, :content, name: "horses_index_named"),
               "horses_index_named index should not exist"
       end
     end
diff --git a/activerecord/test/cases/migration/create_join_table_test.rb b/activerecord/test/cases/migration/create_join_table_test.rb
index a1e5fb1115..e0cbb29dcf 100644
--- a/activerecord/test/cases/migration/create_join_table_test.rb
+++ b/activerecord/test/cases/migration/create_join_table_test.rb
@@ -139,7 +139,7 @@ module ActiveRecord
           assert connection.table_exists?("audio_artists_musics")
 
           connection.drop_join_table "audio_artists", "audio_musics"
-          assert !connection.table_exists?("audio_artists_musics"), "Should have dropped join table, but didn't"
+          assert_not connection.table_exists?("audio_artists_musics"), "Should have dropped join table, but didn't"
         end
       end
 
diff --git a/activerecord/test/cases/migration_test.rb b/activerecord/test/cases/migration_test.rb
index 1fa9a3c34a..d1292dc53d 100644
--- a/activerecord/test/cases/migration_test.rb
+++ b/activerecord/test/cases/migration_test.rb
@@ -262,21 +262,21 @@ class MigrationTest < ActiveRecord::TestCase
 
   def test_instance_based_migration_up
     migration = MockMigration.new
-    assert !migration.went_up, "have not gone up"
-    assert !migration.went_down, "have not gone down"
+    assert_not migration.went_up, "have not gone up"
+    assert_not migration.went_down, "have not gone down"
 
     migration.migrate :up
     assert migration.went_up, "have gone up"
-    assert !migration.went_down, "have not gone down"
+    assert_not migration.went_down, "have not gone down"
   end
 
   def test_instance_based_migration_down
     migration = MockMigration.new
-    assert !migration.went_up, "have not gone up"
-    assert !migration.went_down, "have not gone down"
+    assert_not migration.went_up, "have not gone up"
+    assert_not migration.went_down, "have not gone down"
 
     migration.migrate :down
-    assert !migration.went_up, "have gone up"
+    assert_not migration.went_up, "have gone up"
     assert migration.went_down, "have not gone down"
   end
 
diff --git a/activerecord/test/cases/modules_test.rb b/activerecord/test/cases/modules_test.rb
index 060d555607..87455e4fcb 100644
--- a/activerecord/test/cases/modules_test.rb
+++ b/activerecord/test/cases/modules_test.rb
@@ -32,7 +32,7 @@ class ModulesTest < ActiveRecord::TestCase
 
   def test_module_spanning_associations
     firm = MyApplication::Business::Firm.first
-    assert !firm.clients.empty?, "Firm should have clients"
+    assert_not firm.clients.empty?, "Firm should have clients"
     assert_nil firm.class.table_name.match("::"), "Firm shouldn't have the module appear in its table name"
   end
 
@@ -155,7 +155,7 @@ class ModulesTest < ActiveRecord::TestCase
     ActiveRecord::Base.store_full_sti_class = true
 
     collection = Shop::Collection.first
-    assert !collection.products.empty?, "Collection should have products"
+    assert_not collection.products.empty?, "Collection should have products"
     assert_nothing_raised { collection.destroy }
   ensure
     ActiveRecord::Base.store_full_sti_class = old
@@ -166,7 +166,7 @@ class ModulesTest < ActiveRecord::TestCase
     ActiveRecord::Base.store_full_sti_class = true
 
     product = Shop::Product.first
-    assert !product.variants.empty?, "Product should have variants"
+    assert_not product.variants.empty?, "Product should have variants"
     assert_nothing_raised { product.destroy }
   ensure
     ActiveRecord::Base.store_full_sti_class = old
diff --git a/activerecord/test/cases/persistence_test.rb b/activerecord/test/cases/persistence_test.rb
index 47e9683b44..4c332e30aa 100644
--- a/activerecord/test/cases/persistence_test.rb
+++ b/activerecord/test/cases/persistence_test.rb
@@ -703,8 +703,8 @@ class PersistenceTest < ActiveRecord::TestCase
     t = Topic.first
     t.update_attribute(:title, "super_title")
     assert_equal "super_title", t.title
-    assert !t.changed?, "topic should not have changed"
-    assert !t.title_changed?, "title should not have changed"
+    assert_not t.changed?, "topic should not have changed"
+    assert_not t.title_changed?, "title should not have changed"
     assert_nil t.title_change, "title change should be nil"
 
     t.reload
diff --git a/activerecord/test/cases/query_cache_test.rb b/activerecord/test/cases/query_cache_test.rb
index 393f363e37..0f990bac9d 100644
--- a/activerecord/test/cases/query_cache_test.rb
+++ b/activerecord/test/cases/query_cache_test.rb
@@ -483,14 +483,14 @@ class QueryCacheTest < ActiveRecord::TestCase
     def assert_cache(state, connection = ActiveRecord::Base.connection)
       case state
       when :off
-        assert !connection.query_cache_enabled, "cache should be off"
+        assert_not connection.query_cache_enabled, "cache should be off"
         assert connection.query_cache.empty?, "cache should be empty"
       when :clean
         assert connection.query_cache_enabled, "cache should be on"
         assert connection.query_cache.empty?, "cache should be empty"
       when :dirty
         assert connection.query_cache_enabled, "cache should be on"
-        assert !connection.query_cache.empty?, "cache should be dirty"
+        assert_not connection.query_cache.empty?, "cache should be dirty"
       else
         raise "unknown state"
       end
diff --git a/activerecord/test/cases/relation_test.rb b/activerecord/test/cases/relation_test.rb
index 0f446e06aa..93e2363025 100644
--- a/activerecord/test/cases/relation_test.rb
+++ b/activerecord/test/cases/relation_test.rb
@@ -14,7 +14,7 @@ module ActiveRecord
       relation = Relation.new(FakeKlass, table: :b)
       assert_equal FakeKlass, relation.klass
       assert_equal :b, relation.table
-      assert !relation.loaded, "relation is not loaded"
+      assert_not relation.loaded, "relation is not loaded"
     end
 
     def test_responds_to_model_and_returns_klass
diff --git a/activerecord/test/cases/timestamp_test.rb b/activerecord/test/cases/timestamp_test.rb
index d9f7a81ce4..75ecd6fc40 100644
--- a/activerecord/test/cases/timestamp_test.rb
+++ b/activerecord/test/cases/timestamp_test.rb
@@ -90,8 +90,8 @@ class TimestampTest < ActiveRecord::TestCase
       @developer.touch(:created_at)
     end
 
-    assert !@developer.created_at_changed?, "created_at should not be changed"
-    assert !@developer.changed?, "record should not be changed"
+    assert_not @developer.created_at_changed?, "created_at should not be changed"
+    assert_not @developer.changed?, "record should not be changed"
     assert_not_equal previously_created_at, @developer.created_at
     assert_not_equal @previously_updated_at, @developer.updated_at
   end
diff --git a/activerecord/test/cases/transactions_test.rb b/activerecord/test/cases/transactions_test.rb
index 931e01845a..17aeabe34e 100644
--- a/activerecord/test/cases/transactions_test.rb
+++ b/activerecord/test/cases/transactions_test.rb
@@ -47,7 +47,7 @@ class TransactionTest < ActiveRecord::TestCase
     end
 
     assert Topic.find(1).approved?, "First should have been approved"
-    assert !Topic.find(2).approved?, "Second should have been unapproved"
+    assert_not Topic.find(2).approved?, "Second should have been unapproved"
   end
 
   def transaction_with_return
@@ -80,7 +80,7 @@ class TransactionTest < ActiveRecord::TestCase
     assert committed
 
     assert Topic.find(1).approved?, "First should have been approved"
-    assert !Topic.find(2).approved?, "Second should have been unapproved"
+    assert_not Topic.find(2).approved?, "Second should have been unapproved"
   ensure
     Topic.connection.class_eval do
       remove_method :commit_db_transaction
@@ -121,7 +121,7 @@ class TransactionTest < ActiveRecord::TestCase
     end
 
     assert Topic.find(1).approved?, "First should have been approved"
-    assert !Topic.find(2).approved?, "Second should have been unapproved"
+    assert_not Topic.find(2).approved?, "Second should have been unapproved"
   end
 
   def test_failing_on_exception
@@ -138,9 +138,9 @@ class TransactionTest < ActiveRecord::TestCase
     end
 
     assert @first.approved?, "First should still be changed in the objects"
-    assert !@second.approved?, "Second should still be changed in the objects"
+    assert_not @second.approved?, "Second should still be changed in the objects"
 
-    assert !Topic.find(1).approved?, "First shouldn't have been approved"
+    assert_not Topic.find(1).approved?, "First shouldn't have been approved"
     assert Topic.find(2).approved?, "Second should still be approved"
   end
 
@@ -165,7 +165,7 @@ class TransactionTest < ActiveRecord::TestCase
       @first.approved = true
       @first.save!
     end
-    assert !Topic.find(@first.id).approved?, "Should not commit the approved flag"
+    assert_not Topic.find(@first.id).approved?, "Should not commit the approved flag"
   end
 
   def test_raising_exception_in_nested_transaction_restore_state_in_save
@@ -288,7 +288,7 @@ class TransactionTest < ActiveRecord::TestCase
     }
 
     new_topic = topic.create(title: "A new topic")
-    assert !new_topic.persisted?, "The topic should not be persisted"
+    assert_not new_topic.persisted?, "The topic should not be persisted"
     assert_nil new_topic.id, "The topic should not have an ID"
   end
 
@@ -300,7 +300,7 @@ class TransactionTest < ActiveRecord::TestCase
     }
 
     new_topic = topic.create(title: "A new topic")
-    assert !new_topic.persisted?, "The topic should not be persisted"
+    assert_not new_topic.persisted?, "The topic should not be persisted"
     assert_nil new_topic.id, "The topic should not have an ID"
   end
 
@@ -315,7 +315,7 @@ class TransactionTest < ActiveRecord::TestCase
     end
 
     assert Topic.find(1).approved?, "First should have been approved"
-    assert !Topic.find(2).approved?, "Second should have been unapproved"
+    assert_not Topic.find(2).approved?, "Second should have been unapproved"
   end
 
   def test_nested_transaction_with_new_transaction_applies_parent_state_on_rollback
@@ -399,9 +399,9 @@ class TransactionTest < ActiveRecord::TestCase
     end
 
     assert @first.approved?, "First should still be changed in the objects"
-    assert !@second.approved?, "Second should still be changed in the objects"
+    assert_not @second.approved?, "Second should still be changed in the objects"
 
-    assert !Topic.find(1).approved?, "First shouldn't have been approved"
+    assert_not Topic.find(1).approved?, "First shouldn't have been approved"
     assert Topic.find(2).approved?, "Second should still be approved"
   end
 
@@ -593,7 +593,7 @@ class TransactionTest < ActiveRecord::TestCase
     # about it since there is no specific error
     # for frozen objects.
     assert_match(/frozen/i, e.message)
-    assert !topic.persisted?, "not persisted"
+    assert_not topic.persisted?, "not persisted"
     assert_nil topic.id
     assert topic.frozen?, "not frozen"
   end
@@ -620,9 +620,9 @@ class TransactionTest < ActiveRecord::TestCase
     thread.join
 
     assert @first.approved?, "First should still be changed in the objects"
-    assert !@second.approved?, "Second should still be changed in the objects"
+    assert_not @second.approved?, "Second should still be changed in the objects"
 
-    assert !Topic.find(1).approved?, "First shouldn't have been approved"
+    assert_not Topic.find(1).approved?, "First shouldn't have been approved"
     assert Topic.find(2).approved?, "Second should still be approved"
   end
 
@@ -653,15 +653,15 @@ class TransactionTest < ActiveRecord::TestCase
       raise ActiveRecord::Rollback
     end
 
-    assert !topic_1.persisted?, "not persisted"
+    assert_not topic_1.persisted?, "not persisted"
     assert_nil topic_1.id
-    assert !topic_2.persisted?, "not persisted"
+    assert_not topic_2.persisted?, "not persisted"
     assert_nil topic_2.id
-    assert !topic_3.persisted?, "not persisted"
+    assert_not topic_3.persisted?, "not persisted"
     assert_nil topic_3.id
     assert @first.persisted?, "persisted"
     assert_not_nil @first.id
-    assert !@second.destroyed?, "not destroyed"
+    assert_not @second.destroyed?, "not destroyed"
   end
 
   def test_restore_frozen_state_after_double_destroy
diff --git a/activerecord/test/cases/unconnected_test.rb b/activerecord/test/cases/unconnected_test.rb
index f4d8be5897..9eefc32745 100644
--- a/activerecord/test/cases/unconnected_test.rb
+++ b/activerecord/test/cases/unconnected_test.rb
@@ -30,6 +30,6 @@ class TestUnconnectedAdapter < ActiveRecord::TestCase
   end
 
   def test_underlying_adapter_no_longer_active
-    assert !@underlying.active?, "Removed adapter should no longer be active"
+    assert_not @underlying.active?, "Removed adapter should no longer be active"
   end
 end
diff --git a/activerecord/test/cases/validations/uniqueness_validation_test.rb b/activerecord/test/cases/validations/uniqueness_validation_test.rb
index 941aed5402..8f6f47e5fb 100644
--- a/activerecord/test/cases/validations/uniqueness_validation_test.rb
+++ b/activerecord/test/cases/validations/uniqueness_validation_test.rb
@@ -83,8 +83,8 @@ class UniquenessValidationTest < ActiveRecord::TestCase
     assert t.save, "Should still save t as unique"
 
     t2 = Topic.new("title" => "I'm uniqué!")
-    assert !t2.valid?, "Shouldn't be valid"
-    assert !t2.save, "Shouldn't save t2 as unique"
+    assert_not t2.valid?, "Shouldn't be valid"
+    assert_not t2.save, "Shouldn't save t2 as unique"
     assert_equal ["has already been taken"], t2.errors[:title]
 
     t2.title = "Now I am really also unique"
@@ -106,8 +106,8 @@ class UniquenessValidationTest < ActiveRecord::TestCase
     assert t.save, "Should save t as unique"
 
     t2 = Topic.new("title" => nil)
-    assert !t2.valid?, "Shouldn't be valid"
-    assert !t2.save, "Shouldn't save t2 as unique"
+    assert_not t2.valid?, "Shouldn't be valid"
+    assert_not t2.save, "Shouldn't save t2 as unique"
     assert_equal ["has already been taken"], t2.errors[:title]
   end
 
@@ -146,7 +146,7 @@ class UniquenessValidationTest < ActiveRecord::TestCase
     assert r1.valid?, "Saving r1"
 
     r2 = t.replies.create "title" => "r2", "content" => "hello world"
-    assert !r2.valid?, "Saving r2 first time"
+    assert_not r2.valid?, "Saving r2 first time"
 
     r2.content = "something else"
     assert r2.save, "Saving r2 second time"
@@ -172,7 +172,7 @@ class UniquenessValidationTest < ActiveRecord::TestCase
     assert r1.valid?, "Saving r1"
 
     r2 = t.replies.create "title" => "r2", "content" => "hello world"
-    assert !r2.valid?, "Saving r2 first time"
+    assert_not r2.valid?, "Saving r2 first time"
   end
 
   def test_validate_uniqueness_with_polymorphic_object_scope
@@ -193,7 +193,7 @@ class UniquenessValidationTest < ActiveRecord::TestCase
     assert r1.valid?, "Saving r1"
 
     r2 = ReplyWithTitleObject.create "title" => "r1", "content" => "hello world"
-    assert !r2.valid?, "Saving r2 first time"
+    assert_not r2.valid?, "Saving r2 first time"
   end
 
   def test_validate_uniqueness_with_object_arg
@@ -205,7 +205,7 @@ class UniquenessValidationTest < ActiveRecord::TestCase
     assert r1.valid?, "Saving r1"
 
     r2 = t.replies.create "title" => "r2", "content" => "hello world"
-    assert !r2.valid?, "Saving r2 first time"
+    assert_not r2.valid?, "Saving r2 first time"
   end
 
   def test_validate_uniqueness_scoped_to_defining_class
@@ -215,7 +215,7 @@ class UniquenessValidationTest < ActiveRecord::TestCase
     assert r1.valid?, "Saving r1"
 
     r2 = t.silly_unique_replies.create "title" => "r2", "content" => "a barrel of fun"
-    assert !r2.valid?, "Saving r2"
+    assert_not r2.valid?, "Saving r2"
 
     # Should succeed as validates_uniqueness_of only applies to
     # UniqueReply and its subclasses
@@ -232,19 +232,19 @@ class UniquenessValidationTest < ActiveRecord::TestCase
     assert r1.valid?, "Saving r1"
 
     r2 = t.replies.create "author_name" => "jeremy", "author_email_address" => "jeremy@rubyonrails.com", "title" => "You're crazy!", "content" => "Crazy reply again..."
-    assert !r2.valid?, "Saving r2. Double reply by same author."
+    assert_not r2.valid?, "Saving r2. Double reply by same author."
 
     r2.author_email_address = "jeremy_alt_email@rubyonrails.com"
     assert r2.save, "Saving r2 the second time."
 
     r3 = t.replies.create "author_name" => "jeremy", "author_email_address" => "jeremy_alt_email@rubyonrails.com", "title" => "You're wrong", "content" => "It's cubic"
-    assert !r3.valid?, "Saving r3"
+    assert_not r3.valid?, "Saving r3"
 
     r3.author_name = "jj"
     assert r3.save, "Saving r3 the second time."
 
     r3.author_name = "jeremy"
-    assert !r3.save, "Saving r3 the third time."
+    assert_not r3.save, "Saving r3 the third time."
   end
 
   def test_validate_case_insensitive_uniqueness
@@ -257,15 +257,15 @@ class UniquenessValidationTest < ActiveRecord::TestCase
     assert t.save, "Should still save t as unique"
 
     t2 = Topic.new("title" => "I'm UNIQUE!", :parent_id => 1)
-    assert !t2.valid?, "Shouldn't be valid"
-    assert !t2.save, "Shouldn't save t2 as unique"
+    assert_not t2.valid?, "Shouldn't be valid"
+    assert_not t2.save, "Shouldn't save t2 as unique"
     assert_predicate t2.errors[:title], :any?
     assert_predicate t2.errors[:parent_id], :any?
     assert_equal ["has already been taken"], t2.errors[:title]
 
     t2.title = "I'm truly UNIQUE!"
-    assert !t2.valid?, "Shouldn't be valid"
-    assert !t2.save, "Shouldn't save t2 as unique"
+    assert_not t2.valid?, "Shouldn't be valid"
+    assert_not t2.save, "Shouldn't save t2 as unique"
     assert_empty t2.errors[:title]
     assert_predicate t2.errors[:parent_id], :any?
 
@@ -283,8 +283,8 @@ class UniquenessValidationTest < ActiveRecord::TestCase
     # If database hasn't UTF-8 character set, this test fails
     if Topic.all.merge!(select: "LOWER(title) AS title").find(t_utf8.id).title == "я тоже уникальный!"
       t2_utf8 = Topic.new("title" => "я тоже УНИКАЛЬНЫЙ!")
-      assert !t2_utf8.valid?, "Shouldn't be valid"
-      assert !t2_utf8.save, "Shouldn't save t2_utf8 as unique"
+      assert_not t2_utf8.valid?, "Shouldn't be valid"
+      assert_not t2_utf8.save, "Shouldn't save t2_utf8 as unique"
     end
   end
 
@@ -349,7 +349,7 @@ class UniquenessValidationTest < ActiveRecord::TestCase
 
   def test_validate_uniqueness_with_non_standard_table_names
     i1 = WarehouseThing.create(value: 1000)
-    assert !i1.valid?, "i1 should not be valid"
+    assert_not i1.valid?, "i1 should not be valid"
     assert i1.errors[:value].any?, "Should not be empty"
   end
 
@@ -417,12 +417,12 @@ class UniquenessValidationTest < ActiveRecord::TestCase
 
     # Should use validation from base class (which is abstract)
     w2 = IneptWizard.new(name: "Rincewind", city: "Quirm")
-    assert !w2.valid?, "w2 shouldn't be valid"
+    assert_not w2.valid?, "w2 shouldn't be valid"
     assert w2.errors[:name].any?, "Should have errors for name"
     assert_equal ["has already been taken"], w2.errors[:name], "Should have uniqueness message for name"
 
     w3 = Conjurer.new(name: "Rincewind", city: "Quirm")
-    assert !w3.valid?, "w3 shouldn't be valid"
+    assert_not w3.valid?, "w3 shouldn't be valid"
     assert w3.errors[:name].any?, "Should have errors for name"
     assert_equal ["has already been taken"], w3.errors[:name], "Should have uniqueness message for name"
 
@@ -430,12 +430,12 @@ class UniquenessValidationTest < ActiveRecord::TestCase
     assert w4.valid?, "Saving w4"
 
     w5 = Thaumaturgist.new(name: "The Amazing Bonko", city: "Lancre")
-    assert !w5.valid?, "w5 shouldn't be valid"
+    assert_not w5.valid?, "w5 shouldn't be valid"
     assert w5.errors[:name].any?, "Should have errors for name"
     assert_equal ["has already been taken"], w5.errors[:name], "Should have uniqueness message for name"
 
     w6 = Thaumaturgist.new(name: "Mustrum Ridcully", city: "Quirm")
-    assert !w6.valid?, "w6 shouldn't be valid"
+    assert_not w6.valid?, "w6 shouldn't be valid"
     assert w6.errors[:city].any?, "Should have errors for city"
     assert_equal ["has already been taken"], w6.errors[:city], "Should have uniqueness message for city"
   end
@@ -446,7 +446,7 @@ class UniquenessValidationTest < ActiveRecord::TestCase
     Topic.create("title" => "I'm an unapproved topic", "approved" => false)
 
     t3 = Topic.new("title" => "I'm a topic", "approved" => true)
-    assert !t3.valid?, "t3 shouldn't be valid"
+    assert_not t3.valid?, "t3 shouldn't be valid"
 
     t4 = Topic.new("title" => "I'm an unapproved topic", "approved" => false)
     assert t4.valid?, "t4 should be valid"
diff --git a/activesupport/test/cache/cache_entry_test.rb b/activesupport/test/cache/cache_entry_test.rb
index d7baaa5c72..ec20a288e1 100644
--- a/activesupport/test/cache/cache_entry_test.rb
+++ b/activesupport/test/cache/cache_entry_test.rb
@@ -6,9 +6,9 @@ require "active_support/cache"
 class CacheEntryTest < ActiveSupport::TestCase
   def test_expired
     entry = ActiveSupport::Cache::Entry.new("value")
-    assert !entry.expired?, "entry not expired"
+    assert_not entry.expired?, "entry not expired"
     entry = ActiveSupport::Cache::Entry.new("value", expires_in: 60)
-    assert !entry.expired?, "entry not expired"
+    assert_not entry.expired?, "entry not expired"
     Time.stub(:now, Time.now + 61) do
       assert entry.expired?, "entry is expired"
     end
diff --git a/activesupport/test/cache/stores/memory_store_test.rb b/activesupport/test/cache/stores/memory_store_test.rb
index 340fb517cb..4c0a4f549d 100644
--- a/activesupport/test/cache/stores/memory_store_test.rb
+++ b/activesupport/test/cache/stores/memory_store_test.rb
@@ -33,9 +33,9 @@ class MemoryStorePruningTest < ActiveSupport::TestCase
     @cache.prune(@record_size * 3)
     assert @cache.exist?(5)
     assert @cache.exist?(4)
-    assert !@cache.exist?(3), "no entry"
+    assert_not @cache.exist?(3), "no entry"
     assert @cache.exist?(2)
-    assert !@cache.exist?(1), "no entry"
+    assert_not @cache.exist?(1), "no entry"
   end
 
   def test_prune_size_on_write
@@ -57,12 +57,12 @@ class MemoryStorePruningTest < ActiveSupport::TestCase
     assert @cache.exist?(9)
     assert @cache.exist?(8)
     assert @cache.exist?(7)
-    assert !@cache.exist?(6), "no entry"
-    assert !@cache.exist?(5), "no entry"
+    assert_not @cache.exist?(6), "no entry"
+    assert_not @cache.exist?(5), "no entry"
     assert @cache.exist?(4)
-    assert !@cache.exist?(3), "no entry"
+    assert_not @cache.exist?(3), "no entry"
     assert @cache.exist?(2)
-    assert !@cache.exist?(1), "no entry"
+    assert_not @cache.exist?(1), "no entry"
   end
 
   def test_prune_size_on_write_based_on_key_length
@@ -82,11 +82,11 @@ class MemoryStorePruningTest < ActiveSupport::TestCase
     assert @cache.exist?(8)
     assert @cache.exist?(7)
     assert @cache.exist?(6)
-    assert !@cache.exist?(5), "no entry"
-    assert !@cache.exist?(4), "no entry"
-    assert !@cache.exist?(3), "no entry"
-    assert !@cache.exist?(2), "no entry"
-    assert !@cache.exist?(1), "no entry"
+    assert_not @cache.exist?(5), "no entry"
+    assert_not @cache.exist?(4), "no entry"
+    assert_not @cache.exist?(3), "no entry"
+    assert_not @cache.exist?(2), "no entry"
+    assert_not @cache.exist?(1), "no entry"
   end
 
   def test_pruning_is_capped_at_a_max_time
diff --git a/activesupport/test/core_ext/object/duplicable_test.rb b/activesupport/test/core_ext/object/duplicable_test.rb
index 635dd7f281..5203434ae6 100644
--- a/activesupport/test/core_ext/object/duplicable_test.rb
+++ b/activesupport/test/core_ext/object/duplicable_test.rb
@@ -19,7 +19,7 @@ class DuplicableTest < ActiveSupport::TestCase
                   "* https://github.com/rubinius/rubinius/issues/3089"
 
     RAISE_DUP.each do |v|
-      assert !v.duplicable?, "#{ v.inspect } should not be duplicable"
+      assert_not v.duplicable?, "#{ v.inspect } should not be duplicable"
       assert_raises(TypeError, v.class.name) { v.dup }
     end
 
diff --git a/activesupport/test/dependencies_test.rb b/activesupport/test/dependencies_test.rb
index a4fbab7b55..84cb64a7c2 100644
--- a/activesupport/test/dependencies_test.rb
+++ b/activesupport/test/dependencies_test.rb
@@ -755,7 +755,7 @@ class DependenciesTest < ActiveSupport::TestCase
     Object.const_set :EM, Class.new
     with_autoloading_fixtures do
       require_dependency "em"
-      assert ! ActiveSupport::Dependencies.autoloaded?(:EM), "EM shouldn't be marked autoloaded!"
+      assert_not ActiveSupport::Dependencies.autoloaded?(:EM), "EM shouldn't be marked autoloaded!"
       ActiveSupport::Dependencies.clear
     end
   ensure
@@ -782,7 +782,7 @@ class DependenciesTest < ActiveSupport::TestCase
 
       Object.const_set :M, Module.new
       ActiveSupport::Dependencies.clear
-      assert ! defined?(M), "Dependencies should unload unloadable constants each time"
+      assert_not defined?(M), "Dependencies should unload unloadable constants each time"
     end
   end
 
@@ -980,10 +980,10 @@ class DependenciesTest < ActiveSupport::TestCase
 
   def test_autoload_doesnt_shadow_no_method_error_with_relative_constant
     with_autoloading_fixtures do
-      assert !defined?(::RaisesNoMethodError), "::RaisesNoMethodError is defined but it hasn't been referenced yet!"
+      assert_not defined?(::RaisesNoMethodError), "::RaisesNoMethodError is defined but it hasn't been referenced yet!"
       2.times do
         assert_raise(NoMethodError) { RaisesNoMethodError }
-        assert !defined?(::RaisesNoMethodError), "::RaisesNoMethodError is defined but it should have failed!"
+        assert_not defined?(::RaisesNoMethodError), "::RaisesNoMethodError is defined but it should have failed!"
       end
     end
   ensure
@@ -992,10 +992,10 @@ class DependenciesTest < ActiveSupport::TestCase
 
   def test_autoload_doesnt_shadow_no_method_error_with_absolute_constant
     with_autoloading_fixtures do
-      assert !defined?(::RaisesNoMethodError), "::RaisesNoMethodError is defined but it hasn't been referenced yet!"
+      assert_not defined?(::RaisesNoMethodError), "::RaisesNoMethodError is defined but it hasn't been referenced yet!"
       2.times do
         assert_raise(NoMethodError) { ::RaisesNoMethodError }
-        assert !defined?(::RaisesNoMethodError), "::RaisesNoMethodError is defined but it should have failed!"
+        assert_not defined?(::RaisesNoMethodError), "::RaisesNoMethodError is defined but it should have failed!"
       end
     end
   ensure
@@ -1020,13 +1020,13 @@ class DependenciesTest < ActiveSupport::TestCase
           ::RaisesNameError::FooBarBaz.object_id
         end
         assert_equal "uninitialized constant RaisesNameError::FooBarBaz", e.message
-        assert !defined?(::RaisesNameError), "::RaisesNameError is defined but it should have failed!"
+        assert_not defined?(::RaisesNameError), "::RaisesNameError is defined but it should have failed!"
       end
 
       assert_not defined?(::RaisesNameError)
       2.times do
         assert_raise(NameError) { ::RaisesNameError }
-        assert !defined?(::RaisesNameError), "::RaisesNameError is defined but it should have failed!"
+        assert_not defined?(::RaisesNameError), "::RaisesNameError is defined but it should have failed!"
       end
     end
   ensure
diff --git a/activesupport/test/gzip_test.rb b/activesupport/test/gzip_test.rb
index 05ce12fe86..3d790f69c4 100644
--- a/activesupport/test/gzip_test.rb
+++ b/activesupport/test/gzip_test.rb
@@ -18,7 +18,7 @@ class GzipTest < ActiveSupport::TestCase
     compressed = ActiveSupport::Gzip.compress("")
 
     assert_equal Encoding.find("binary"), compressed.encoding
-    assert !compressed.blank?, "a compressed blank string should not be blank"
+    assert_not compressed.blank?, "a compressed blank string should not be blank"
   end
 
   def test_compress_should_return_gzipped_string_by_compression_level
diff --git a/activesupport/test/hash_with_indifferent_access_test.rb b/activesupport/test/hash_with_indifferent_access_test.rb
index a20c428bf8..eebff18ef1 100644
--- a/activesupport/test/hash_with_indifferent_access_test.rb
+++ b/activesupport/test/hash_with_indifferent_access_test.rb
@@ -606,7 +606,7 @@ class HashWithIndifferentAccessTest < ActiveSupport::TestCase
   def test_assorted_keys_not_stringified
     original = { Object.new => 2, 1 => 2, [] => true }
     indiff = original.with_indifferent_access
-    assert(!indiff.keys.any? { |k| k.kind_of? String }, "A key was converted to a string!")
+    assert_not(indiff.keys.any? { |k| k.kind_of? String }, "A key was converted to a string!")
   end
 
   def test_deep_merge_on_indifferent_access
diff --git a/activesupport/test/safe_buffer_test.rb b/activesupport/test/safe_buffer_test.rb
index 1c19c92bb0..9456bb8753 100644
--- a/activesupport/test/safe_buffer_test.rb
+++ b/activesupport/test/safe_buffer_test.rb
@@ -141,13 +141,13 @@ class SafeBufferTest < ActiveSupport::TestCase
     x = "foo".html_safe.gsub!("f", '<script>alert("lolpwnd");</script>')
 
     # calling gsub! makes the dirty flag true
-    assert !x.html_safe?, "should not be safe"
+    assert_not x.html_safe?, "should not be safe"
 
     # getting a slice of it
     y = x[0..-1]
 
     # should still be unsafe
-    assert !y.html_safe?, "should not be safe"
+    assert_not y.html_safe?, "should not be safe"
   end
 
   test "Should work with interpolation (array argument)" do
diff --git a/ci/custom_cops/lib/custom_cops/assert_not.rb b/ci/custom_cops/lib/custom_cops/assert_not.rb
index e722448e21..8b49d3eac2 100644
--- a/ci/custom_cops/lib/custom_cops/assert_not.rb
+++ b/ci/custom_cops/lib/custom_cops/assert_not.rb
@@ -14,7 +14,7 @@ module CustomCops
   class AssertNot < RuboCop::Cop::Cop
     MSG = "Prefer `assert_not` over `assert !`"
 
-    def_node_matcher :offensive?, "(send nil? :assert (send ... :!))"
+    def_node_matcher :offensive?, "(send nil? :assert (send ... :!) ...)"
 
     def on_send(node)
       add_offense(node) if offensive?(node)
diff --git a/railties/test/application/assets_test.rb b/railties/test/application/assets_test.rb
index 9ef123c5b6..4ca6d02b85 100644
--- a/railties/test/application/assets_test.rb
+++ b/railties/test/application/assets_test.rb
@@ -47,7 +47,7 @@ module ApplicationTests
     end
 
     def assert_no_file_exists(filename)
-      assert !File.exist?(filename), "#{filename} does exist"
+      assert_not File.exist?(filename), "#{filename} does exist"
     end
 
     test "assets routes have higher priority" do
diff --git a/railties/test/application/paths_test.rb b/railties/test/application/paths_test.rb
index 0abc5cc9aa..28a9206daa 100644
--- a/railties/test/application/paths_test.rb
+++ b/railties/test/application/paths_test.rb
@@ -37,7 +37,7 @@ module ApplicationTests
     end
 
     def assert_not_in_load_path(*path)
-      assert !$:.any? { |p| File.expand_path(p) == root(*path) }, "Load path includes '#{root(*path)}'. They are:\n-----\n #{$:.join("\n")}\n-----"
+      assert_not $:.any? { |p| File.expand_path(p) == root(*path) }, "Load path includes '#{root(*path)}'. They are:\n-----\n #{$:.join("\n")}\n-----"
     end
 
     test "booting up Rails yields a valid paths object" do
diff --git a/railties/test/application/rake/migrations_test.rb b/railties/test/application/rake/migrations_test.rb
index bf5b07afbd..47c5ac105a 100644
--- a/railties/test/application/rake/migrations_test.rb
+++ b/railties/test/application/rake/migrations_test.rb
@@ -417,7 +417,7 @@ module ApplicationTests
           version = output =~ %r{[^/]+db/migrate/(\d+)_create_authors\.rb} && $1
 
           rails "db:migrate", "db:rollback", "db:forward", "db:migrate:up", "db:migrate:down", "VERSION=#{version}"
-          assert !File.exist?("db/schema.rb"), "should not dump schema when configured not to"
+          assert_not File.exist?("db/schema.rb"), "should not dump schema when configured not to"
         end
 
         add_to_config("config.active_record.dump_schema_after_migration = true")