Resolve cop_helper use offenses p4

- follow internal affairs cop.

.rubocop_manual_todo.yml

@@ -28,39 +28,6 @@ FactoryBot/InlineAssociation:
     - 'spec/factories/uploads.rb'
     - 'spec/factories/wiki_pages.rb'
 
-InternalAffairs/DeprecateCopHelper: # issue to resolve: https://gitlab.com/gitlab-org/gitlab/-/issues/276734
-  Exclude:
-    - 'spec/rubocop/cop/migration/safer_boolean_column_spec.rb'
-    - 'spec/rubocop/cop/migration/remove_index_spec.rb'
-    - 'spec/rubocop/cop/migration/add_index_spec.rb'
-    - 'spec/rubocop/cop/migration/drop_table_spec.rb'
-    - 'spec/rubocop/cop/migration/hash_index_spec.rb'
-    - 'spec/rubocop/cop/migration/datetime_spec.rb'
-    - 'spec/rubocop/cop/migration/add_column_with_default_spec.rb'
-    - 'spec/rubocop/cop/migration/prevent_strings_spec.rb'
-    - 'spec/rubocop/cop/migration/add_timestamps_spec.rb'
-    - 'spec/rubocop/cop/migration/add_concurrent_index_spec.rb'
-    - 'spec/rubocop/cop/migration/update_column_in_batches_spec.rb'
-    - 'spec/rubocop/cop/migration/complex_indexes_require_name_spec.rb'
-    - 'spec/rubocop/cop/migration/refer_to_index_by_name_spec.rb'
-    - 'spec/rubocop/cop/migration/schedule_async_spec.rb'
-    - 'spec/rubocop/cop/migration/timestamps_spec.rb'
-    - 'spec/rubocop/cop/migration/remove_concurrent_index_spec.rb'
-    - 'spec/rubocop/cop/migration/add_columns_to_wide_tables_spec.rb'
-    - 'spec/rubocop/cop/migration/with_lock_retries_disallowed_method_spec.rb'
-    - 'spec/rubocop/cop/migration/add_reference_spec.rb'
-    - 'spec/rubocop/cop/migration/remove_column_spec.rb'
-    - 'spec/rubocop/cop/migration/create_table_with_foreign_keys_spec.rb'
-    - 'spec/rubocop/cop/migration/add_concurrent_foreign_key_spec.rb'
-    - 'spec/rubocop/cop/migration/with_lock_retries_with_change_spec.rb'
-    - 'spec/rubocop/cop/migration/add_limit_to_text_columns_spec.rb'
-    - 'spec/rubocop/cop/avoid_return_from_blocks_spec.rb'
-    - 'spec/rubocop/cop/avoid_route_redirect_leading_slash_spec.rb'
-    - 'spec/rubocop/cop/put_group_routes_under_scope_spec.rb'
-    - 'spec/rubocop/cop/sidekiq_options_queue_spec.rb'
-    - 'spec/rubocop/cop/ignored_columns_spec.rb'
-    - 'spec/rubocop/cop/prefer_class_methods_over_module_spec.rb'
-
 Rails/SaveBang:
   Exclude:
     - 'ee/spec/controllers/projects/merge_requests_controller_spec.rb'

rubocop/cop/migration/add_columns_to_wide_tables.rb

@@ -9,8 +9,8 @@ module RuboCop
       class AddColumnsToWideTables < RuboCop::Cop::Cop
         include MigrationHelpers
 
-        MSG = '`%s` is a wide table with several columns, addig more should be avoided unless absolutely necessary.' \
-              ' Consider storing the column in a different table or creating a new one.'.freeze
+        MSG = '`%s` is a wide table with several columns, adding more should be avoided unless absolutely necessary.' \
+              ' Consider storing the column in a different table or creating a new one.'
 
         BLACKLISTED_METHODS = %i[
           add_column

spec/rubocop/cop/avoid_return_from_blocks_spec.rb

@@ -5,8 +5,6 @@ require 'rubocop'
 require_relative '../../../rubocop/cop/avoid_return_from_blocks'
 
 RSpec.describe RuboCop::Cop::AvoidReturnFromBlocks do
-  include CopHelper
-
   subject(:cop) { described_class.new }
 
   it 'flags violation for return inside a block' do
@@ -19,20 +17,16 @@ RSpec.describe RuboCop::Cop::AvoidReturnFromBlocks do
     RUBY
   end
 
-  it "doesn't call add_offense twice for nested blocks" do
-    source = <<~RUBY
+  it "doesn't create more than one offense for nested blocks" do
+    expect_offense(<<~RUBY)
       call do
         call do
           something
           return if something_else
+          ^^^^^^ Do not return from a block, use next or break instead.
         end
       end
     RUBY
-    expect_any_instance_of(described_class) do |instance|
-      expect(instance).to receive(:add_offense).once
-    end
-
-    inspect_source(source)
   end
 
   it 'flags violation for return inside included > def > block' do

spec/rubocop/cop/avoid_route_redirect_leading_slash_spec.rb

@@ -5,19 +5,21 @@ require 'rubocop'
 require_relative '../../../rubocop/cop/avoid_route_redirect_leading_slash'
 
 RSpec.describe RuboCop::Cop::AvoidRouteRedirectLeadingSlash do
-  include CopHelper
-
   subject(:cop) { described_class.new }
 
   before do
     allow(cop).to receive(:in_routes?).and_return(true)
   end
 
-  it 'registers an offense when redirect has a leading slash' do
+  it 'registers an offense when redirect has a leading slash and corrects', :aggregate_failures do
     expect_offense(<<~PATTERN)
       root to: redirect("/-/route")
                ^^^^^^^^^^^^^^^^^^^^ Do not use a leading "/" in route redirects
     PATTERN
+
+    expect_correction(<<~PATTERN)
+      root to: redirect("-/route")
+    PATTERN
   end
 
   it 'does not register an offense when redirect does not have a leading slash' do
@@ -25,8 +27,4 @@ RSpec.describe RuboCop::Cop::AvoidRouteRedirectLeadingSlash do
       root to: redirect("-/route")
     PATTERN
   end
-
-  it 'autocorrect `/-/route` to `-/route`' do
-    expect(autocorrect_source('redirect("/-/route")')).to eq('redirect("-/route")')
-  end
 end

spec/rubocop/cop/ignored_columns_spec.rb

@@ -2,21 +2,17 @@
 
 require 'fast_spec_helper'
 require 'rubocop'
-require 'rubocop/rspec/support'
 require_relative '../../../rubocop/cop/ignored_columns'
 
 RSpec.describe RuboCop::Cop::IgnoredColumns do
-  include CopHelper
-
   subject(:cop) { described_class.new }
 
-  it 'flags the use of destroy_all with a local variable receiver' do
-    inspect_source(<<~RUBY)
+  it 'flags direct use of ignored_columns instead of the IgnoredColumns concern' do
+    expect_offense(<<~RUBY)
       class Foo < ApplicationRecord
         self.ignored_columns += %i[id]
+        ^^^^^^^^^^^^^^^^^^^^ Use `IgnoredColumns` concern instead of adding to `self.ignored_columns`.
       end
     RUBY
-
-    expect(cop.offenses.size).to eq(1)
   end
 end

spec/rubocop/cop/migration/add_column_with_default_spec.rb

@@ -5,11 +5,9 @@ require 'rubocop'
 require_relative '../../../../rubocop/cop/migration/add_column_with_default'
 
 RSpec.describe RuboCop::Cop::Migration::AddColumnWithDefault do
-  include CopHelper
-
   let(:cop) { described_class.new }
 
-  context 'outside of a migration' do
+  context 'when outside of a migration' do
     it 'does not register any offenses' do
       expect_no_offenses(<<~RUBY)
         def up
@@ -19,18 +17,16 @@ RSpec.describe RuboCop::Cop::Migration::AddColumnWithDefault do
     end
   end
 
-  context 'in a migration' do
+  context 'when in a migration' do
     before do
       allow(cop).to receive(:in_migration?).and_return(true)
     end
 
-    let(:offense) { '`add_column_with_default` is deprecated, use `add_column` instead' }
-
     it 'registers an offense' do
       expect_offense(<<~RUBY)
         def up
           add_column_with_default(:merge_request_diff_files, :artifacts, :boolean, default: true, allow_null: false)
-          ^^^^^^^^^^^^^^^^^^^^^^^ #{offense}
+          ^^^^^^^^^^^^^^^^^^^^^^^ `add_column_with_default` is deprecated, use `add_column` instead
         end
       RUBY
     end

spec/rubocop/cop/migration/add_columns_to_wide_tables_spec.rb

@@ -5,11 +5,9 @@ require 'rubocop'
 require_relative '../../../../rubocop/cop/migration/add_columns_to_wide_tables'
 
 RSpec.describe RuboCop::Cop::Migration::AddColumnsToWideTables do
-  include CopHelper
-
   let(:cop) { described_class.new }
 
-  context 'outside of a migration' do
+  context 'when outside of a migration' do
     it 'does not register any offenses' do
       expect_no_offenses(<<~RUBY)
         def up
@@ -19,14 +17,14 @@ RSpec.describe RuboCop::Cop::Migration::AddColumnsToWideTables do
     end
   end
 
-  context 'in a migration' do
+  context 'when in a migration' do
     before do
       allow(cop).to receive(:in_migration?).and_return(true)
     end
 
     context 'with wide tables' do
       it 'registers an offense when adding a column to a wide table' do
-        offense = '`projects` is a wide table with several columns, addig more should be avoided unless absolutely necessary. Consider storing the column in a different table or creating a new one.'
+        offense = '`projects` is a wide table with several columns, [...]'
 
         expect_offense(<<~RUBY)
           def up
@@ -37,7 +35,7 @@ RSpec.describe RuboCop::Cop::Migration::AddColumnsToWideTables do
       end
 
       it 'registers an offense when adding a column with default to a wide table' do
-        offense = '`users` is a wide table with several columns, addig more should be avoided unless absolutely necessary. Consider storing the column in a different table or creating a new one.'
+        offense = '`users` is a wide table with several columns, [...]'
 
         expect_offense(<<~RUBY)
           def up
@@ -48,7 +46,7 @@ RSpec.describe RuboCop::Cop::Migration::AddColumnsToWideTables do
       end
 
       it 'registers an offense when adding a reference' do
-        offense = '`ci_builds` is a wide table with several columns, addig more should be avoided unless absolutely necessary. Consider storing the column in a different table or creating a new one.'
+        offense = '`ci_builds` is a wide table with several columns, [...]'
 
         expect_offense(<<~RUBY)
           def up
@@ -59,7 +57,7 @@ RSpec.describe RuboCop::Cop::Migration::AddColumnsToWideTables do
       end
 
       it 'registers an offense when adding timestamps' do
-        offense = '`projects` is a wide table with several columns, addig more should be avoided unless absolutely necessary. Consider storing the column in a different table or creating a new one.'
+        offense = '`projects` is a wide table with several columns, [...]'
 
         expect_offense(<<~RUBY)
           def up

spec/rubocop/cop/migration/add_concurrent_foreign_key_spec.rb

@@ -5,46 +5,38 @@ require 'rubocop'
 require_relative '../../../../rubocop/cop/migration/add_concurrent_foreign_key'
 
 RSpec.describe RuboCop::Cop::Migration::AddConcurrentForeignKey do
-  include CopHelper
-
   let(:cop) { described_class.new }
 
-  context 'outside of a migration' do
+  context 'when outside of a migration' do
     it 'does not register any offenses' do
-      inspect_source('def up; add_foreign_key(:projects, :users, column: :user_id); end')
-
-      expect(cop.offenses).to be_empty
+      expect_no_offenses('def up; add_foreign_key(:projects, :users, column: :user_id); end')
     end
   end
 
-  context 'in a migration' do
+  context 'when in a migration' do
     before do
       allow(cop).to receive(:in_migration?).and_return(true)
     end
 
     it 'registers an offense when using add_foreign_key' do
-      inspect_source('def up; add_foreign_key(:projects, :users, column: :user_id); end')
-
-      aggregate_failures do
-        expect(cop.offenses.size).to eq(1)
-        expect(cop.offenses.map(&:line)).to eq([1])
+      expect_offense(<<~RUBY)
+        def up
+          add_foreign_key(:projects, :users, column: :user_id)
+          ^^^^^^^^^^^^^^^ `add_foreign_key` requires downtime, use `add_concurrent_foreign_key` instead
         end
+      RUBY
     end
 
     it 'does not register an offense when a `NOT VALID` foreign key is added' do
-      inspect_source('def up; add_foreign_key(:projects, :users, column: :user_id, validate: false); end')
-
-      expect(cop.offenses).to be_empty
+      expect_no_offenses('def up; add_foreign_key(:projects, :users, column: :user_id, validate: false); end')
     end
 
     it 'does not register an offense when `add_foreign_key` is within `with_lock_retries`' do
-      inspect_source <<~RUBY
+      expect_no_offenses(<<~RUBY)
         with_lock_retries do
           add_foreign_key :key, :projects, column: :project_id, on_delete: :cascade
         end
       RUBY
-
-      expect(cop.offenses).to be_empty
     end
   end
 end

spec/rubocop/cop/migration/add_concurrent_index_spec.rb

@@ -5,36 +5,30 @@ require 'rubocop'
 require_relative '../../../../rubocop/cop/migration/add_concurrent_index'
 
 RSpec.describe RuboCop::Cop::Migration::AddConcurrentIndex do
-  include CopHelper
-
   subject(:cop) { described_class.new }
 
-  context 'in migration' do
+  context 'when in migration' do
     before do
       allow(cop).to receive(:in_migration?).and_return(true)
     end
 
     it 'registers an offense when add_concurrent_index is used inside a change method' do
-      inspect_source('def change; add_concurrent_index :table, :column; end')
-
-      aggregate_failures do
-        expect(cop.offenses.size).to eq(1)
-        expect(cop.offenses.map(&:line)).to eq([1])
+      expect_offense(<<~RUBY)
+        def change
+            ^^^^^^ `add_concurrent_index` is not reversible[...]
+          add_concurrent_index :table, :column
         end
+      RUBY
     end
 
     it 'registers no offense when add_concurrent_index is used inside an up method' do
-      inspect_source('def up; add_concurrent_index :table, :column; end')
-
-      expect(cop.offenses.size).to eq(0)
+      expect_no_offenses('def up; add_concurrent_index :table, :column; end')
     end
   end
 
-  context 'outside of migration' do
+  context 'when outside of migration' do
     it 'registers no offense' do
-      inspect_source('def change; add_concurrent_index :table, :column; end')
-
-      expect(cop.offenses.size).to eq(0)
+      expect_no_offenses('def change; add_concurrent_index :table, :column; end')
     end
   end
 end

spec/rubocop/cop/migration/add_index_spec.rb

@@ -5,8 +5,6 @@ require 'rubocop'
 require_relative '../../../../rubocop/cop/migration/add_index'
 
 RSpec.describe RuboCop::Cop::Migration::AddIndex do
-  include CopHelper
-
   subject(:cop) { described_class.new }
 
   context 'in migration' do

spec/rubocop/cop/migration/add_limit_to_text_columns_spec.rb

@@ -5,11 +5,11 @@ require 'rubocop'
 require_relative '../../../../rubocop/cop/migration/add_limit_to_text_columns'
 
 RSpec.describe RuboCop::Cop::Migration::AddLimitToTextColumns do
-  include CopHelper
-
   subject(:cop) { described_class.new }
 
-  context 'in migration' do
+  context 'when in migration' do
+    let(:msg) { 'Text columns should always have a limit set (255 is suggested)[...]' }
+
     before do
       allow(cop).to receive(:in_migration?).and_return(true)
     end
@@ -25,31 +25,29 @@ RSpec.describe RuboCop::Cop::Migration::AddLimitToTextColumns do
               create_table :test_text_limits, id: false do |t|
                 t.integer :test_id, null: false
                 t.text :name
-                  ^^^^ #{described_class::MSG}
+                  ^^^^ #{msg}
               end
 
               create_table_with_constraints :test_text_limits_create do |t|
                 t.integer :test_id, null: false
                 t.text :title
                 t.text :description
-                  ^^^^ #{described_class::MSG}
+                  ^^^^ #{msg}
 
                 t.text_limit :title, 100
               end
 
               add_column :test_text_limits, :email, :text
-              ^^^^^^^^^^ #{described_class::MSG}
+              ^^^^^^^^^^ #{msg}
 
               add_column_with_default :test_text_limits, :role, :text, default: 'default'
-              ^^^^^^^^^^^^^^^^^^^^^^^ #{described_class::MSG}
+              ^^^^^^^^^^^^^^^^^^^^^^^ #{msg}
 
               change_column_type_concurrently :test_text_limits, :test_id, :text
-              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ #{described_class::MSG}
+              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ #{msg}
             end
           end
         RUBY
-
-        expect(cop.offenses.map(&:cop_name)).to all(eq('Migration/AddLimitToTextColumns'))
       end
     end
 
@@ -111,7 +109,7 @@ RSpec.describe RuboCop::Cop::Migration::AddLimitToTextColumns do
     end
 
     # Make sure that the cop is properly checking for an `add_text_limit`
-    # over the same {table, attribute} as the one that triggered the offence
+    # over the same {table, attribute} as the one that triggered the offense
     context 'when the limit is defined for a same name attribute but different table' do
       it 'registers an offense' do
         expect_offense(<<~RUBY)
@@ -123,17 +121,17 @@ RSpec.describe RuboCop::Cop::Migration::AddLimitToTextColumns do
               create_table :test_text_limits, id: false do |t|
                 t.integer :test_id, null: false
                 t.text :name
-                  ^^^^ #{described_class::MSG}
+                  ^^^^ #{msg}
               end
 
               add_column :test_text_limits, :email, :text
-              ^^^^^^^^^^ #{described_class::MSG}
+              ^^^^^^^^^^ #{msg}
 
               add_column_with_default :test_text_limits, :role, :text, default: 'default'
-              ^^^^^^^^^^^^^^^^^^^^^^^ #{described_class::MSG}
+              ^^^^^^^^^^^^^^^^^^^^^^^ #{msg}
 
               change_column_type_concurrently :test_text_limits, :test_id, :text
-              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ #{described_class::MSG}
+              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ #{msg}
 
               add_text_limit :wrong_table, :name, 255
               add_text_limit :wrong_table, :email, 255
@@ -142,8 +140,6 @@ RSpec.describe RuboCop::Cop::Migration::AddLimitToTextColumns do
             end
           end
         RUBY
-
-        expect(cop.offenses.map(&:cop_name)).to all(eq('Migration/AddLimitToTextColumns'))
       end
     end
 
@@ -176,18 +172,18 @@ RSpec.describe RuboCop::Cop::Migration::AddLimitToTextColumns do
             DOWNTIME = false
 
             def up
-              drop_table :no_offence_on_down
+              drop_table :no_offense_on_down
             end
 
             def down
-              create_table :no_offence_on_down, id: false do |t|
+              create_table :no_offense_on_down, id: false do |t|
                 t.integer :test_id, null: false
                 t.text :name
               end
 
-              add_column :no_offence_on_down, :email, :text
+              add_column :no_offense_on_down, :email, :text
 
-              add_column_with_default :no_offence_on_down, :role, :text, default: 'default'
+              add_column_with_default :no_offense_on_down, :role, :text, default: 'default'
             end
           end
         RUBY
@@ -195,7 +191,7 @@ RSpec.describe RuboCop::Cop::Migration::AddLimitToTextColumns do
     end
   end
 
-  context 'outside of migration' do
+  context 'when outside of migration' do
     it 'registers no offense' do
       expect_no_offenses(<<~RUBY)
         class TestTextLimits < ActiveRecord::Migration[6.0]

spec/rubocop/cop/migration/add_reference_spec.rb

@@ -5,11 +5,9 @@ require 'rubocop'
 require_relative '../../../../rubocop/cop/migration/add_reference'
 
 RSpec.describe RuboCop::Cop::Migration::AddReference do
-  include CopHelper
-
   let(:cop) { described_class.new }
 
-  context 'outside of a migration' do
+  context 'when outside of a migration' do
     it 'does not register any offenses' do
       expect_no_offenses(<<~RUBY)
         def up
@@ -19,12 +17,12 @@ RSpec.describe RuboCop::Cop::Migration::AddReference do
     end
   end
 
-  context 'in a migration' do
+  context 'when in a migration' do
     before do
       allow(cop).to receive(:in_migration?).and_return(true)
     end
 
-    let(:offense) { '`add_reference` requires downtime for existing tables, use `add_concurrent_foreign_key` instead. When used for new tables, `index: true` or `index: { options... } is required.`' }
+    let(:offense) { '`add_reference` requires downtime for existing tables, use `add_concurrent_foreign_key`[...]' }
 
     context 'when the table existed before' do
       it 'registers an offense when using add_reference' do

spec/rubocop/cop/migration/add_timestamps_spec.rb

@@ -5,8 +5,6 @@ require 'rubocop'
 require_relative '../../../../rubocop/cop/migration/add_timestamps'
 
 RSpec.describe RuboCop::Cop::Migration::AddTimestamps do
-  include CopHelper
-
   subject(:cop) { described_class.new }
 
   let(:migration_with_add_timestamps) do
@@ -47,44 +45,39 @@ RSpec.describe RuboCop::Cop::Migration::AddTimestamps do
     )
   end
 
-  context 'in migration' do
+  context 'when in migration' do
     before do
       allow(cop).to receive(:in_migration?).and_return(true)
     end
 
     it 'registers an offense when the "add_timestamps" method is used' do
-      inspect_source(migration_with_add_timestamps)
+      expect_offense(<<~RUBY)
+        class Users < ActiveRecord::Migration[4.2]
+          DOWNTIME = false
 
-      aggregate_failures do
-        expect(cop.offenses.size).to eq(1)
-        expect(cop.offenses.map(&:line)).to eq([7])
+          def change
+            add_column(:users, :username, :text)
+            add_timestamps(:users)
+            ^^^^^^^^^^^^^^ Do not use `add_timestamps`, use `add_timestamps_with_timezone` instead
           end
         end
+      RUBY
+    end
 
     it 'does not register an offense when the "add_timestamps" method is not used' do
-      inspect_source(migration_without_add_timestamps)
-
-      aggregate_failures do
-        expect(cop.offenses.size).to eq(0)
-      end
+      expect_no_offenses(migration_without_add_timestamps)
     end
 
     it 'does not register an offense when the "add_timestamps_with_timezone" method is used' do
-      inspect_source(migration_with_add_timestamps_with_timezone)
-
-      aggregate_failures do
-        expect(cop.offenses.size).to eq(0)
-      end
+      expect_no_offenses(migration_with_add_timestamps_with_timezone)
     end
   end
 
-  context 'outside of migration' do
-    it 'registers no offense' do
-      inspect_source(migration_with_add_timestamps)
-      inspect_source(migration_without_add_timestamps)
-      inspect_source(migration_with_add_timestamps_with_timezone)
-
-      expect(cop.offenses.size).to eq(0)
+  context 'when outside of migration' do
+    it 'registers no offense', :aggregate_failures do
+      expect_no_offenses(migration_with_add_timestamps)
+      expect_no_offenses(migration_without_add_timestamps)
+      expect_no_offenses(migration_with_add_timestamps_with_timezone)
     end
   end
 end

spec/rubocop/cop/migration/complex_indexes_require_name_spec.rb

@@ -5,11 +5,11 @@ require 'rubocop'
 require_relative '../../../../rubocop/cop/migration/complex_indexes_require_name'
 
 RSpec.describe RuboCop::Cop::Migration::ComplexIndexesRequireName do
-  include CopHelper
-
   subject(:cop) { described_class.new }
 
-  context 'in migration' do
+  context 'when in migration' do
+    let(:msg) { 'indexes added with custom options must be explicitly named' }
+
     before do
       allow(cop).to receive(:in_migration?).and_return(true)
     end
@@ -29,9 +29,9 @@ RSpec.describe RuboCop::Cop::Migration::ComplexIndexesRequireName do
 
                   t.index :column1, unique: true
                   t.index :column2, where: 'column1 = 0'
-                    ^^^^^ #{described_class::MSG}
+                    ^^^^^ #{msg}
                   t.index :column3, using: :gin
-                    ^^^^^ #{described_class::MSG}
+                    ^^^^^ #{msg}
                 end
               end
 
@@ -40,8 +40,6 @@ RSpec.describe RuboCop::Cop::Migration::ComplexIndexesRequireName do
               end
             end
           RUBY
-
-          expect(cop.offenses.map(&:cop_name)).to all(eq("Migration/#{described_class.name.demodulize}"))
         end
       end
 
@@ -85,20 +83,18 @@ RSpec.describe RuboCop::Cop::Migration::ComplexIndexesRequireName do
                 add_index :test_indexes, :column1
 
                 add_index :test_indexes, :column2, where: "column2 = 'value'", order: { column4: :desc }
-                ^^^^^^^^^ #{described_class::MSG}
+                ^^^^^^^^^ #{msg}
               end
 
               def down
                 add_index :test_indexes, :column4, 'unique' => true, where: 'column4 IS NOT NULL'
-                ^^^^^^^^^ #{described_class::MSG}
+                ^^^^^^^^^ #{msg}
 
                 add_concurrent_index :test_indexes, :column6, using: :gin, opclass: :gin_trgm_ops
-                ^^^^^^^^^^^^^^^^^^^^ #{described_class::MSG}
+                ^^^^^^^^^^^^^^^^^^^^ #{msg}
               end
             end
           RUBY
-
-          expect(cop.offenses.map(&:cop_name)).to all(eq("Migration/#{described_class.name.demodulize}"))
         end
       end
 
@@ -132,7 +128,7 @@ RSpec.describe RuboCop::Cop::Migration::ComplexIndexesRequireName do
     end
   end
 
-  context 'outside migration' do
+  context 'when outside migration' do
     before do
       allow(cop).to receive(:in_migration?).and_return(false)
     end

spec/rubocop/cop/migration/create_table_with_foreign_keys_spec.rb

@@ -5,8 +5,6 @@ require 'rubocop'
 require_relative '../../../../rubocop/cop/migration/create_table_with_foreign_keys'
 
 RSpec.describe RuboCop::Cop::Migration::CreateTableWithForeignKeys do
-  include CopHelper
-
   let(:cop) { described_class.new }
 
   context 'outside of a migration' do
@@ -22,7 +20,7 @@ RSpec.describe RuboCop::Cop::Migration::CreateTableWithForeignKeys do
     end
   end
 
-  context 'in a migration' do
+  context 'when in a migration' do
     before do
       allow(cop).to receive(:in_migration?).and_return(true)
     end

spec/rubocop/cop/migration/datetime_spec.rb

@@ -5,40 +5,8 @@ require 'rubocop'
 require_relative '../../../../rubocop/cop/migration/datetime'
 
 RSpec.describe RuboCop::Cop::Migration::Datetime do
-  include CopHelper
-
   subject(:cop) { described_class.new }
 
-  let(:create_table_migration_with_datetime) do
-    %q(
-      class Users < ActiveRecord::Migration[6.0]
-        DOWNTIME = false
-
-        def change
-          create_table :users do |t|
-            t.string :username, null: false
-            t.datetime :last_sign_in
-          end
-        end
-      end
-    )
-  end
-
-  let(:create_table_migration_with_timestamp) do
-    %q(
-      class Users < ActiveRecord::Migration[6.0]
-        DOWNTIME = false
-
-        def change
-          create_table :users do |t|
-            t.string :username, null: false
-            t.timestamp :last_sign_in
-          end
-        end
-      end
-    )
-  end
-
   let(:create_table_migration_without_datetime) do
     %q(
       class Users < ActiveRecord::Migration[6.0]
@@ -120,92 +88,94 @@ RSpec.describe RuboCop::Cop::Migration::Datetime do
     )
   end
 
-  context 'in migration' do
+  context 'when in migration' do
     before do
       allow(cop).to receive(:in_migration?).and_return(true)
     end
 
     it 'registers an offense when the ":datetime" data type is used on create_table' do
-      inspect_source(create_table_migration_with_datetime)
+      expect_offense(<<~RUBY)
+        class Users < ActiveRecord::Migration[6.0]
+          DOWNTIME = false
 
-      aggregate_failures do
-        expect(cop.offenses.size).to eq(1)
-        expect(cop.offenses.map(&:line)).to eq([8])
-        expect(cop.offenses.first.message).to include('`datetime`')
+          def change
+            create_table :users do |t|
+              t.string :username, null: false
+              t.datetime :last_sign_in
+                ^^^^^^^^ Do not use the `datetime` data type[...]
+            end
           end
         end
+      RUBY
+    end
 
     it 'registers an offense when the ":timestamp" data type is used on create_table' do
-      inspect_source(create_table_migration_with_timestamp)
+      expect_offense(<<~RUBY)
+        class Users < ActiveRecord::Migration[6.0]
+          DOWNTIME = false
 
-      aggregate_failures do
-        expect(cop.offenses.size).to eq(1)
-        expect(cop.offenses.map(&:line)).to eq([8])
-        expect(cop.offenses.first.message).to include('timestamp')
+          def change
+            create_table :users do |t|
+              t.string :username, null: false
+              t.timestamp :last_sign_in
+                ^^^^^^^^^ Do not use the `timestamp` data type[...]
+            end
           end
         end
+      RUBY
+    end
 
     it 'does not register an offense when the ":datetime" data type is not used on create_table' do
-      inspect_source(create_table_migration_without_datetime)
-
-      aggregate_failures do
-        expect(cop.offenses.size).to eq(0)
-      end
+      expect_no_offenses(create_table_migration_without_datetime)
     end
 
     it 'does not register an offense when the ":datetime_with_timezone" data type is used on create_table' do
-      inspect_source(create_table_migration_with_datetime_with_timezone)
-
-      aggregate_failures do
-        expect(cop.offenses.size).to eq(0)
-      end
+      expect_no_offenses(create_table_migration_with_datetime_with_timezone)
     end
 
     it 'registers an offense when the ":datetime" data type is used on add_column' do
-      inspect_source(add_column_migration_with_datetime)
+      expect_offense(<<~RUBY)
+        class Users < ActiveRecord::Migration[6.0]
+          DOWNTIME = false
 
-      aggregate_failures do
-        expect(cop.offenses.size).to eq(1)
-        expect(cop.offenses.map(&:line)).to eq([7])
-        expect(cop.offenses.first.message).to include('`datetime`')
+          def change
+            add_column(:users, :username, :text)
+            add_column(:users, :last_sign_in, :datetime)
+            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Do not use the `datetime` data type[...]
           end
         end
+      RUBY
+    end
 
     it 'registers an offense when the ":timestamp" data type is used on add_column' do
-      inspect_source(add_column_migration_with_timestamp)
+      expect_offense(<<~RUBY)
+        class Users < ActiveRecord::Migration[6.0]
+          DOWNTIME = false
 
-      aggregate_failures do
-        expect(cop.offenses.size).to eq(1)
-        expect(cop.offenses.map(&:line)).to eq([7])
-        expect(cop.offenses.first.message).to include('timestamp')
+          def change
+            add_column(:users, :username, :text)
+            add_column(:users, :last_sign_in, :timestamp)
+            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Do not use the `timestamp` data type[...]
           end
         end
+      RUBY
+    end
 
     it 'does not register an offense when the ":datetime" data type is not used on add_column' do
-      inspect_source(add_column_migration_without_datetime)
-
-      aggregate_failures do
-        expect(cop.offenses.size).to eq(0)
-      end
+      expect_no_offenses(add_column_migration_without_datetime)
     end
 
     it 'does not register an offense when the ":datetime_with_timezone" data type is used on add_column' do
-      inspect_source(add_column_migration_with_datetime_with_timezone)
-
-      aggregate_failures do
-        expect(cop.offenses.size).to eq(0)
+      expect_no_offenses(add_column_migration_with_datetime_with_timezone)
     end
   end
-  end
-
-  context 'outside of migration' do
-    it 'registers no offense' do
-      inspect_source(add_column_migration_with_datetime)
-      inspect_source(add_column_migration_with_timestamp)
-      inspect_source(add_column_migration_without_datetime)
-      inspect_source(add_column_migration_with_datetime_with_timezone)
 
-      expect(cop.offenses.size).to eq(0)
+  context 'when outside of migration' do
+    it 'registers no offense', :aggregate_failures do
+      expect_no_offenses(add_column_migration_with_datetime)
+      expect_no_offenses(add_column_migration_with_timestamp)
+      expect_no_offenses(add_column_migration_without_datetime)
+      expect_no_offenses(add_column_migration_with_datetime_with_timezone)
     end
   end
 end

spec/rubocop/cop/migration/drop_table_spec.rb

@@ -5,11 +5,13 @@ require 'rubocop'
 require_relative '../../../../rubocop/cop/migration/drop_table'
 
 RSpec.describe RuboCop::Cop::Migration::DropTable do
-  include CopHelper
-
   subject(:cop) { described_class.new }
 
   context 'when in deployment migration' do
+    let(:msg) do
+      '`drop_table` in deployment migrations requires downtime. Drop tables in post-deployment migrations instead.'
+    end
+
     before do
       allow(cop).to receive(:in_deployment_migration?).and_return(true)
     end
@@ -30,7 +32,7 @@ RSpec.describe RuboCop::Cop::Migration::DropTable do
           expect_offense(<<~PATTERN)
             def up
               drop_table :table
-              ^^^^^^^^^^ #{described_class::MSG}
+              ^^^^^^^^^^  #{msg}
             end
           PATTERN
         end
@@ -41,7 +43,7 @@ RSpec.describe RuboCop::Cop::Migration::DropTable do
           expect_offense(<<~PATTERN)
             def change
               drop_table :table
-              ^^^^^^^^^^ #{described_class::MSG}
+              ^^^^^^^^^^  #{msg}
             end
           PATTERN
         end
@@ -63,7 +65,7 @@ RSpec.describe RuboCop::Cop::Migration::DropTable do
         expect_offense(<<~PATTERN)
           def up
             execute "DROP TABLE table"
-            ^^^^^^^ #{described_class::MSG}
+            ^^^^^^^  #{msg}
           end
         PATTERN
       end
@@ -74,7 +76,7 @@ RSpec.describe RuboCop::Cop::Migration::DropTable do
         expect_offense(<<~PATTERN)
           def change
             execute "DROP TABLE table"
-            ^^^^^^^ #{described_class::MSG}
+            ^^^^^^^  #{msg}
           end
         PATTERN
       end

spec/rubocop/cop/migration/hash_index_spec.rb

@@ -5,48 +5,44 @@ require 'rubocop'
 require_relative '../../../../rubocop/cop/migration/hash_index'
 
 RSpec.describe RuboCop::Cop::Migration::HashIndex do
-  include CopHelper
-
   subject(:cop) { described_class.new }
 
-  context 'in migration' do
+  context 'when in migration' do
     before do
       allow(cop).to receive(:in_migration?).and_return(true)
     end
 
     it 'registers an offense when creating a hash index' do
-      inspect_source('def change; add_index :table, :column, using: :hash; end')
-
-      aggregate_failures do
-        expect(cop.offenses.size).to eq(1)
-        expect(cop.offenses.map(&:line)).to eq([1])
+      expect_offense(<<~RUBY)
+        def change
+          add_index :table, :column, using: :hash
+                                     ^^^^^^^^^^^^ hash indexes should be avoided at all costs[...]
         end
+      RUBY
     end
 
     it 'registers an offense when creating a concurrent hash index' do
-      inspect_source('def change; add_concurrent_index :table, :column, using: :hash; end')
-
-      aggregate_failures do
-        expect(cop.offenses.size).to eq(1)
-        expect(cop.offenses.map(&:line)).to eq([1])
+      expect_offense(<<~RUBY)
+        def change
+          add_concurrent_index :table, :column, using: :hash
+                                                ^^^^^^^^^^^^ hash indexes should be avoided at all costs[...]
         end
+      RUBY
     end
 
     it 'registers an offense when creating a hash index using t.index' do
-      inspect_source('def change; t.index :table, :column, using: :hash; end')
-
-      aggregate_failures do
-        expect(cop.offenses.size).to eq(1)
-        expect(cop.offenses.map(&:line)).to eq([1])
+      expect_offense(<<~RUBY)
+        def change
+          t.index :table, :column, using: :hash
+                                   ^^^^^^^^^^^^ hash indexes should be avoided at all costs[...]
         end
+      RUBY
     end
   end
 
-  context 'outside of migration' do
+  context 'when outside of migration' do
     it 'registers no offense' do
-      inspect_source('def change; index :table, :column, using: :hash; end')
-
-      expect(cop.offenses.size).to eq(0)
+      expect_no_offenses('def change; index :table, :column, using: :hash; end')
     end
   end
 end

spec/rubocop/cop/migration/prevent_strings_spec.rb

@@ -5,45 +5,41 @@ require 'rubocop'
 require_relative '../../../../rubocop/cop/migration/prevent_strings'
 
 RSpec.describe RuboCop::Cop::Migration::PreventStrings do
-  include CopHelper
-
   subject(:cop) { described_class.new }
 
-  context 'in migration' do
+  context 'when in migration' do
     before do
       allow(cop).to receive(:in_migration?).and_return(true)
     end
 
     context 'when the string data type is used' do
       it 'registers an offense' do
-        expect_offense(<<~RUBY)
+        expect_offense(<<~RUBY, msg: "Do not use the `string` data type, use `text` instead.[...]")
           class Users < ActiveRecord::Migration[6.0]
             DOWNTIME = false
 
             def up
               create_table :users do |t|
                 t.string :username, null: false
-                  ^^^^^^ #{described_class::MSG}
+                  ^^^^^^ %{msg}
 
                 t.timestamps_with_timezone null: true
 
                 t.string :password
-                  ^^^^^^ #{described_class::MSG}
+                  ^^^^^^ %{msg}
               end
 
               add_column(:users, :bio, :string)
-              ^^^^^^^^^^ #{described_class::MSG}
+              ^^^^^^^^^^ %{msg}
 
               add_column_with_default(:users, :url, :string, default: '/-/user', allow_null: false, limit: 255)
-              ^^^^^^^^^^^^^^^^^^^^^^^ #{described_class::MSG}
+              ^^^^^^^^^^^^^^^^^^^^^^^ %{msg}
 
               change_column_type_concurrently :users, :commit_id, :string
-              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ #{described_class::MSG}
+              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ %{msg}
             end
           end
         RUBY
-
-        expect(cop.offenses.map(&:cop_name)).to all(eq('Migration/PreventStrings'))
       end
     end
 
@@ -109,7 +105,7 @@ RSpec.describe RuboCop::Cop::Migration::PreventStrings do
       end
     end
 
-    context 'on down' do
+    context 'when using down method' do
       it 'registers no offense' do
         expect_no_offenses(<<~RUBY)
           class Users < ActiveRecord::Migration[6.0]
@@ -138,7 +134,7 @@ RSpec.describe RuboCop::Cop::Migration::PreventStrings do
     end
   end
 
-  context 'outside of migration' do
+  context 'when outside of migration' do
     it 'registers no offense' do
       expect_no_offenses(<<~RUBY)
         class Users < ActiveRecord::Migration[6.0]

spec/rubocop/cop/migration/refer_to_index_by_name_spec.rb

@@ -5,18 +5,16 @@ require 'rubocop'
 require_relative '../../../../rubocop/cop/migration/refer_to_index_by_name'
 
 RSpec.describe RuboCop::Cop::Migration::ReferToIndexByName do
-  include CopHelper
-
   subject(:cop) { described_class.new }
 
-  context 'in migration' do
+  context 'when in migration' do
     before do
       allow(cop).to receive(:in_migration?).and_return(true)
     end
 
     context 'when existing indexes are referred to without an explicit name' do
       it 'registers an offense' do
-        expect_offense(<<~RUBY)
+        expect_offense(<<~RUBY, msg: 'migration methods that refer to existing indexes must do so by name')
           class TestReferToIndexByName < ActiveRecord::Migration[6.0]
             DOWNTIME = false
 
@@ -30,22 +28,22 @@ RSpec.describe RuboCop::Cop::Migration::ReferToIndexByName do
               end
 
               if index_exists? :test_indexes, :column2
-                 ^^^^^^^^^^^^^ #{described_class::MSG}
+                 ^^^^^^^^^^^^^ %{msg}
                 remove_index :test_indexes, :column2
-                ^^^^^^^^^^^^ #{described_class::MSG}
+                ^^^^^^^^^^^^ %{msg}
               end
 
               remove_index :test_indexes, column: column3
-              ^^^^^^^^^^^^ #{described_class::MSG}
+              ^^^^^^^^^^^^ %{msg}
 
               remove_index :test_indexes, name: 'index_name_4'
             end
 
             def down
               if index_exists? :test_indexes, :column4, using: :gin, opclass: :gin_trgm_ops
-                 ^^^^^^^^^^^^^ #{described_class::MSG}
+                 ^^^^^^^^^^^^^ %{msg}
                 remove_concurrent_index :test_indexes, :column4, using: :gin, opclass: :gin_trgm_ops
-                ^^^^^^^^^^^^^^^^^^^^^^^ #{described_class::MSG}
+                ^^^^^^^^^^^^^^^^^^^^^^^ %{msg}
               end
 
               if index_exists? :test_indexes, :column3, unique: true, name: 'index_name_3', where: 'column3 = 10'
@@ -54,13 +52,11 @@ RSpec.describe RuboCop::Cop::Migration::ReferToIndexByName do
             end
           end
         RUBY
-
-        expect(cop.offenses.map(&:cop_name)).to all(eq("Migration/#{described_class.name.demodulize}"))
       end
     end
   end
 
-  context 'outside migration' do
+  context 'when outside migration' do
     before do
       allow(cop).to receive(:in_migration?).and_return(false)
     end

spec/rubocop/cop/migration/remove_column_spec.rb

@@ -5,63 +5,55 @@ require 'rubocop'
 require_relative '../../../../rubocop/cop/migration/remove_column'
 
 RSpec.describe RuboCop::Cop::Migration::RemoveColumn do
-  include CopHelper
-
   subject(:cop) { described_class.new }
 
   def source(meth = 'change')
     "def #{meth}; remove_column :table, :column; end"
   end
 
-  context 'in a regular migration' do
+  context 'when in a regular migration' do
     before do
       allow(cop).to receive(:in_migration?).and_return(true)
       allow(cop).to receive(:in_post_deployment_migration?).and_return(false)
     end
 
     it 'registers an offense when remove_column is used in the change method' do
-      inspect_source(source('change'))
-
-      aggregate_failures do
-        expect(cop.offenses.size).to eq(1)
-        expect(cop.offenses.map(&:line)).to eq([1])
+      expect_offense(<<~RUBY)
+        def change
+          remove_column :table, :column
+          ^^^^^^^^^^^^^ `remove_column` must only be used in post-deployment migrations
         end
+      RUBY
     end
 
     it 'registers an offense when remove_column is used in the up method' do
-      inspect_source(source('up'))
-
-      aggregate_failures do
-        expect(cop.offenses.size).to eq(1)
-        expect(cop.offenses.map(&:line)).to eq([1])
+      expect_offense(<<~RUBY)
+        def up
+          remove_column :table, :column
+          ^^^^^^^^^^^^^ `remove_column` must only be used in post-deployment migrations
         end
+      RUBY
     end
 
     it 'registers no offense when remove_column is used in the down method' do
-      inspect_source(source('down'))
-
-      expect(cop.offenses.size).to eq(0)
+      expect_no_offenses(source('down'))
     end
   end
 
-  context 'in a post-deployment migration' do
+  context 'when in a post-deployment migration' do
     before do
       allow(cop).to receive(:in_migration?).and_return(true)
       allow(cop).to receive(:in_post_deployment_migration?).and_return(true)
     end
 
     it 'registers no offense' do
-      inspect_source(source)
-
-      expect(cop.offenses.size).to eq(0)
+      expect_no_offenses(source)
     end
   end
 
-  context 'outside of a migration' do
+  context 'when outside of a migration' do
     it 'registers no offense' do
-      inspect_source(source)
-
-      expect(cop.offenses.size).to eq(0)
+      expect_no_offenses(source)
     end
   end
 end

spec/rubocop/cop/migration/remove_concurrent_index_spec.rb

@@ -5,8 +5,6 @@ require 'rubocop'
 require_relative '../../../../rubocop/cop/migration/remove_concurrent_index'
 
 RSpec.describe RuboCop::Cop::Migration::RemoveConcurrentIndex do
-  include CopHelper
-
   subject(:cop) { described_class.new }
 
   context 'in migration' do
@@ -15,26 +13,22 @@ RSpec.describe RuboCop::Cop::Migration::RemoveConcurrentIndex do
     end
 
     it 'registers an offense when remove_concurrent_index is used inside a change method' do
-      inspect_source('def change; remove_concurrent_index :table, :column; end')
-
-      aggregate_failures do
-        expect(cop.offenses.size).to eq(1)
-        expect(cop.offenses.map(&:line)).to eq([1])
+      expect_offense(<<~RUBY)
+        def change
+            ^^^^^^ `remove_concurrent_index` is not reversible [...]
+          remove_concurrent_index :table, :column
         end
+      RUBY
     end
 
     it 'registers no offense when remove_concurrent_index is used inside an up method' do
-      inspect_source('def up; remove_concurrent_index :table, :column; end')
-
-      expect(cop.offenses.size).to eq(0)
+      expect_no_offenses('def up; remove_concurrent_index :table, :column; end')
     end
   end
 
   context 'outside of migration' do
     it 'registers no offense' do
-      inspect_source('def change; remove_concurrent_index :table, :column; end')
-
-      expect(cop.offenses.size).to eq(0)
+      expect_no_offenses('def change; remove_concurrent_index :table, :column; end')
     end
   end
 end

spec/rubocop/cop/migration/remove_index_spec.rb

@@ -5,30 +5,26 @@ require 'rubocop'
 require_relative '../../../../rubocop/cop/migration/remove_index'
 
 RSpec.describe RuboCop::Cop::Migration::RemoveIndex do
-  include CopHelper
-
   subject(:cop) { described_class.new }
 
-  context 'in migration' do
+  context 'when in migration' do
     before do
       allow(cop).to receive(:in_migration?).and_return(true)
     end
 
     it 'registers an offense when remove_index is used' do
-      inspect_source('def change; remove_index :table, :column; end')
-
-      aggregate_failures do
-        expect(cop.offenses.size).to eq(1)
-        expect(cop.offenses.map(&:line)).to eq([1])
+      expect_offense(<<~RUBY)
+        def change
+          remove_index :table, :column
+          ^^^^^^^^^^^^ `remove_index` requires downtime, use `remove_concurrent_index` instead
         end
+      RUBY
     end
   end
 
-  context 'outside of migration' do
+  context 'when outside of migration' do
     it 'registers no offense' do
-      inspect_source('def change; remove_index :table, :column; end')
-
-      expect(cop.offenses.size).to eq(0)
+      expect_no_offenses('def change; remove_index :table, :column; end')
     end
   end
 end

spec/rubocop/cop/migration/safer_boolean_column_spec.rb

@@ -5,8 +5,6 @@ require 'rubocop'
 require_relative '../../../../rubocop/cop/migration/safer_boolean_column'
 
 RSpec.describe RuboCop::Cop::Migration::SaferBooleanColumn do
-  include CopHelper
-
   subject(:cop) { described_class.new }
 
   context 'in migration' do
@@ -31,11 +29,10 @@ RSpec.describe RuboCop::Cop::Migration::SaferBooleanColumn do
         sources_and_offense.each do |source, offense|
           context "given the source \"#{source}\"" do
             it "registers the offense matching \"#{offense}\"" do
-              inspect_source(source)
-
-              aggregate_failures do
-                expect(cop.offenses.first.message).to match(offense)
-              end
+              expect_offense(<<~RUBY, node: source, msg: offense)
+                %{node}
+                ^{node} Boolean columns on the `#{table}` table %{msg}.[...]
+              RUBY
             end
           end
         end
@@ -48,11 +45,7 @@ RSpec.describe RuboCop::Cop::Migration::SaferBooleanColumn do
         inoffensive_sources.each do |source|
           context "given the source \"#{source}\"" do
             it "registers no offense" do
-              inspect_source(source)
-
-              aggregate_failures do
-                expect(cop.offenses).to be_empty
-              end
+              expect_no_offenses(source)
             end
           end
         end
@@ -60,25 +53,19 @@ RSpec.describe RuboCop::Cop::Migration::SaferBooleanColumn do
     end
 
     it 'registers no offense for tables not listed in SMALL_TABLES' do
-      inspect_source("add_column :large_table, :column, :boolean")
-
-      expect(cop.offenses).to be_empty
+      expect_no_offenses("add_column :large_table, :column, :boolean")
     end
 
     it 'registers no offense for non-boolean columns' do
       table = described_class::SMALL_TABLES.sample
-      inspect_source("add_column :#{table}, :column, :string")
-
-      expect(cop.offenses).to be_empty
+      expect_no_offenses("add_column :#{table}, :column, :string")
     end
   end
 
   context 'outside of migration' do
     it 'registers no offense' do
       table = described_class::SMALL_TABLES.sample
-      inspect_source("add_column :#{table}, :column, :boolean")
-
-      expect(cop.offenses).to be_empty
+      expect_no_offenses("add_column :#{table}, :column, :boolean")
     end
   end
 end

spec/rubocop/cop/migration/schedule_async_spec.rb

@@ -3,13 +3,9 @@
 require 'fast_spec_helper'
 
 require 'rubocop'
-require 'rubocop/rspec/support'
-
 require_relative '../../../../rubocop/cop/migration/schedule_async'
 
 RSpec.describe RuboCop::Cop::Migration::ScheduleAsync do
-  include CopHelper
-
   let(:cop) { described_class.new }
   let(:source) do
     <<~SOURCE
@@ -21,9 +17,7 @@ RSpec.describe RuboCop::Cop::Migration::ScheduleAsync do
 
   shared_examples 'a disabled cop' do
     it 'does not register any offenses' do
-      inspect_source(source)
-
-      expect(cop.offenses).to be_empty
+      expect_no_offenses(source)
     end
   end
 
@@ -50,101 +44,73 @@ RSpec.describe RuboCop::Cop::Migration::ScheduleAsync do
       end
 
       context 'BackgroundMigrationWorker.perform_async' do
-        it 'adds an offence when calling `BackgroundMigrationWorker.peform_async`' do
-          inspect_source(source)
-
-          expect(cop.offenses.size).to eq(1)
+        it 'adds an offense when calling `BackgroundMigrationWorker.peform_async` and corrects', :aggregate_failures do
+          expect_offense(<<~RUBY)
+            def up
+              BackgroundMigrationWorker.perform_async(ClazzName, "Bar", "Baz")
+              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Don't call [...]
             end
+          RUBY
 
-        it 'autocorrects to the right version' do
-          correct_source = <<~CORRECT
+          expect_correction(<<~RUBY)
             def up
               migrate_async(ClazzName, "Bar", "Baz")
             end
-          CORRECT
-
-          expect(autocorrect_source(source)).to eq(correct_source)
+          RUBY
         end
       end
 
       context 'BackgroundMigrationWorker.perform_in' do
-        let(:source) do
-          <<~SOURCE
+        it 'adds an offense and corrects', :aggregate_failures do
+          expect_offense(<<~RUBY)
             def up
               BackgroundMigrationWorker
+              ^^^^^^^^^^^^^^^^^^^^^^^^^ Don't call [...]
                 .perform_in(delay, ClazzName, "Bar", "Baz")
             end
-          SOURCE
-        end
-
-        it 'adds an offence' do
-          inspect_source(source)
-
-          expect(cop.offenses.size).to eq(1)
-        end
+          RUBY
 
-        it 'autocorrects to the right version' do
-          correct_source = <<~CORRECT
+          expect_correction(<<~RUBY)
             def up
               migrate_in(delay, ClazzName, "Bar", "Baz")
             end
-          CORRECT
-
-          expect(autocorrect_source(source)).to eq(correct_source)
+          RUBY
         end
       end
 
       context 'BackgroundMigrationWorker.bulk_perform_async' do
-        let(:source) do
-          <<~SOURCE
+        it 'adds an offense and corrects', :aggregate_failures do
+          expect_offense(<<~RUBY)
             def up
               BackgroundMigrationWorker
+              ^^^^^^^^^^^^^^^^^^^^^^^^^ Don't call [...]
                 .bulk_perform_async(jobs)
             end
-          SOURCE
-        end
-
-        it 'adds an offence' do
-          inspect_source(source)
-
-          expect(cop.offenses.size).to eq(1)
-        end
+          RUBY
 
-        it 'autocorrects to the right version' do
-          correct_source = <<~CORRECT
+          expect_correction(<<~RUBY)
             def up
               bulk_migrate_async(jobs)
             end
-          CORRECT
-
-          expect(autocorrect_source(source)).to eq(correct_source)
+          RUBY
         end
       end
 
       context 'BackgroundMigrationWorker.bulk_perform_in' do
-        let(:source) do
-          <<~SOURCE
+        it 'adds an offense and corrects', :aggregate_failures do
+          expect_offense(<<~RUBY)
             def up
               BackgroundMigrationWorker
+              ^^^^^^^^^^^^^^^^^^^^^^^^^ Don't call [...]
                 .bulk_perform_in(5.minutes, jobs)
             end
-          SOURCE
-        end
-
-        it 'adds an offence' do
-          inspect_source(source)
+          RUBY
 
-          expect(cop.offenses.size).to eq(1)
-        end
-
-        it 'autocorrects to the right version' do
-          correct_source = <<~CORRECT
+          expect_correction(<<~RUBY)
             def up
               bulk_migrate_in(5.minutes, jobs)
             end
-          CORRECT
-
-          expect(autocorrect_source(source)).to eq(correct_source)
+          RUBY
         end
       end
     end

spec/rubocop/cop/migration/timestamps_spec.rb

@@ -5,8 +5,6 @@ require 'rubocop'
 require_relative '../../../../rubocop/cop/migration/timestamps'
 
 RSpec.describe RuboCop::Cop::Migration::Timestamps do
-  include CopHelper
-
   subject(:cop) { described_class.new }
 
   let(:migration_with_timestamps) do
@@ -62,38 +60,36 @@ RSpec.describe RuboCop::Cop::Migration::Timestamps do
     end
 
     it 'registers an offense when the "timestamps" method is used' do
-      inspect_source(migration_with_timestamps)
+      expect_offense(<<~RUBY)
+        class Users < ActiveRecord::Migration[4.2]
+          DOWNTIME = false
 
-      aggregate_failures do
-        expect(cop.offenses.size).to eq(1)
-        expect(cop.offenses.map(&:line)).to eq([8])
+          def change
+            create_table :users do |t|
+              t.string :username, null: false
+              t.timestamps null: true
+                ^^^^^^^^^^ Do not use `timestamps`, use `timestamps_with_timezone` instead
+              t.string :password
             end
           end
+        end
+      RUBY
+    end
 
     it 'does not register an offense when the "timestamps" method is not used' do
-      inspect_source(migration_without_timestamps)
-
-      aggregate_failures do
-        expect(cop.offenses.size).to eq(0)
-      end
+      expect_no_offenses(migration_without_timestamps)
     end
 
     it 'does not register an offense when the "timestamps_with_timezone" method is used' do
-      inspect_source(migration_with_timestamps_with_timezone)
-
-      aggregate_failures do
-        expect(cop.offenses.size).to eq(0)
-      end
+      expect_no_offenses(migration_with_timestamps_with_timezone)
     end
   end
 
   context 'outside of migration' do
-    it 'registers no offense' do
-      inspect_source(migration_with_timestamps)
-      inspect_source(migration_without_timestamps)
-      inspect_source(migration_with_timestamps_with_timezone)
-
-      expect(cop.offenses.size).to eq(0)
+    it 'registers no offense', :aggregate_failures do
+      expect_no_offenses(migration_with_timestamps)
+      expect_no_offenses(migration_without_timestamps)
+      expect_no_offenses(migration_with_timestamps_with_timezone)
     end
   end
 end

spec/rubocop/cop/migration/update_column_in_batches_spec.rb

@@ -3,8 +3,6 @@
 require 'fast_spec_helper'
 
 require 'rubocop'
-require 'rubocop/rspec/support'
-
 require_relative '../../../../rubocop/cop/migration/update_column_in_batches'
 
 RSpec.describe RuboCop::Cop::Migration::UpdateColumnInBatches do
@@ -31,9 +29,7 @@ RSpec.describe RuboCop::Cop::Migration::UpdateColumnInBatches do
 
   context 'outside of a migration' do
     it 'does not register any offenses' do
-      inspect_source(migration_code)
-
-      expect(cop.offenses).to be_empty
+      expect_no_offenses(migration_code)
     end
   end
 
@@ -53,15 +49,15 @@ RSpec.describe RuboCop::Cop::Migration::UpdateColumnInBatches do
     let(:relative_spec_filepath) { Pathname.new(spec_filepath).relative_path_from(tmp_rails_root) }
 
     it 'registers an offense when using update_column_in_batches' do
-      inspect_source(migration_code, @migration_file)
-
-      aggregate_failures do
-        expect(cop.offenses.size).to eq(1)
-        expect(cop.offenses.map(&:line)).to eq([2])
-        expect(cop.offenses.first.message)
-          .to include("`#{relative_spec_filepath}`")
+      expect_offense(<<~RUBY, @migration_file)
+        def up
+          update_column_in_batches(:projects, :name, "foo") do |table, query|
+          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Migration running `update_column_in_batches` [...]
+            query.where(table[:name].eq(nil))
           end
         end
+      RUBY
+    end
   end
 
   shared_examples 'a migration file with a spec file' do
@@ -76,20 +72,18 @@ RSpec.describe RuboCop::Cop::Migration::UpdateColumnInBatches do
     end
 
     it 'does not register any offenses' do
-      inspect_source(migration_code, @migration_file)
-
-      expect(cop.offenses).to be_empty
+      expect_no_offenses(migration_code)
     end
   end
 
-  context 'in a migration' do
+  context 'when in migration' do
     let(:migration_filepath) { File.join(tmp_rails_root, 'db', 'migrate', '20121220064453_my_super_migration.rb') }
 
     it_behaves_like 'a migration file with no spec file'
     it_behaves_like 'a migration file with a spec file'
   end
 
-  context 'in a post migration' do
+  context 'when in a post migration' do
     let(:migration_filepath) { File.join(tmp_rails_root, 'db', 'post_migrate', '20121220064453_my_super_migration.rb') }
 
     it_behaves_like 'a migration file with no spec file'
@@ -99,14 +93,14 @@ RSpec.describe RuboCop::Cop::Migration::UpdateColumnInBatches do
   context 'EE migrations' do
     let(:spec_filepath) { File.join(tmp_rails_root, 'ee', 'spec', 'migrations', 'my_super_migration_spec.rb') }
 
-    context 'in a migration' do
+    context 'when in a migration' do
       let(:migration_filepath) { File.join(tmp_rails_root, 'ee', 'db', 'migrate', '20121220064453_my_super_migration.rb') }
 
       it_behaves_like 'a migration file with no spec file'
       it_behaves_like 'a migration file with a spec file'
     end
 
-    context 'in a post migration' do
+    context 'when in a post migration' do
       let(:migration_filepath) { File.join(tmp_rails_root, 'ee', 'db', 'post_migrate', '20121220064453_my_super_migration.rb') }
 
       it_behaves_like 'a migration file with no spec file'

spec/rubocop/cop/migration/with_lock_retries_disallowed_method_spec.rb

@@ -5,60 +5,55 @@ require 'rubocop'
 require_relative '../../../../rubocop/cop/migration/with_lock_retries_disallowed_method'
 
 RSpec.describe RuboCop::Cop::Migration::WithLockRetriesDisallowedMethod do
-  include CopHelper
-
   subject(:cop) { described_class.new }
 
-  context 'in migration' do
+  context 'when in migration' do
     before do
       allow(cop).to receive(:in_migration?).and_return(true)
     end
 
     it 'registers an offense when `with_lock_retries` block has disallowed method' do
-      inspect_source('def change; with_lock_retries { disallowed_method }; end')
-
-      aggregate_failures do
-        expect(cop.offenses.size).to eq(1)
-        expect(cop.offenses.map(&:line)).to eq([1])
+      expect_offense(<<~RUBY)
+        def change
+          with_lock_retries { disallowed_method }
+                              ^^^^^^^^^^^^^^^^^ The method is not allowed [...]
         end
+      RUBY
     end
 
     it 'registers an offense when `with_lock_retries` block has disallowed methods' do
-      source = <<~HEREDOC
+      expect_offense(<<~RUBY)
         def change
           with_lock_retries do
             disallowed_method
+            ^^^^^^^^^^^^^^^^^ The method is not allowed [...]
 
             create_table do |t|
               t.text :text
             end
 
             other_disallowed_method
+            ^^^^^^^^^^^^^^^^^^^^^^^ The method is not allowed [...]
 
             add_column :users, :name
           end
         end
-      HEREDOC
-
-      inspect_source(source)
-
-      aggregate_failures do
-        expect(cop.offenses.size).to eq(2)
-        expect(cop.offenses.map(&:line)).to eq([3, 9])
-      end
+      RUBY
     end
 
     it 'registers no offense when `with_lock_retries` has only allowed method' do
-      inspect_source('def up; with_lock_retries { add_foreign_key :foo, :bar }; end')
-
-      expect(cop.offenses.size).to eq(0)
+      expect_no_offenses(<<~RUBY)
+        def up
+          with_lock_retries { add_foreign_key :foo, :bar }
+        end
+      RUBY
     end
 
     describe 'for `add_foreign_key`' do
       it 'registers an offense when more than two FKs are added' do
         message = described_class::MSG_ONLY_ONE_FK_ALLOWED
 
-        expect_offense <<~RUBY
+        expect_offense(<<~RUBY)
           with_lock_retries do
             add_foreign_key :imports, :projects, column: :project_id, on_delete: :cascade
             ^^^^^^^^^^^^^^^ #{message}
@@ -71,11 +66,13 @@ RSpec.describe RuboCop::Cop::Migration::WithLockRetriesDisallowedMethod do
     end
   end
 
-  context 'outside of migration' do
+  context 'when outside of migration' do
     it 'registers no offense' do
-      inspect_source('def change; with_lock_retries { disallowed_method }; end')
-
-      expect(cop.offenses.size).to eq(0)
+      expect_no_offenses(<<~RUBY)
+        def change
+          with_lock_retries { disallowed_method }
+        end
+      RUBY
     end
   end
 end

spec/rubocop/cop/migration/with_lock_retries_with_change_spec.rb

@@ -5,36 +5,38 @@ require 'rubocop'
 require_relative '../../../../rubocop/cop/migration/with_lock_retries_with_change'
 
 RSpec.describe RuboCop::Cop::Migration::WithLockRetriesWithChange do
-  include CopHelper
-
   subject(:cop) { described_class.new }
 
-  context 'in migration' do
+  context 'when in migration' do
     before do
       allow(cop).to receive(:in_migration?).and_return(true)
     end
 
     it 'registers an offense when `with_lock_retries` is used inside a `change` method' do
-      inspect_source('def change; with_lock_retries {}; end')
-
-      aggregate_failures do
-        expect(cop.offenses.size).to eq(1)
-        expect(cop.offenses.map(&:line)).to eq([1])
+      expect_offense(<<~RUBY)
+        def change
+            ^^^^^^ `with_lock_retries` cannot be used within `change` [...]
+          with_lock_retries {}
         end
+      RUBY
     end
 
     it 'registers no offense when `with_lock_retries` is used inside an `up` method' do
-      inspect_source('def up; with_lock_retries {}; end')
-
-      expect(cop.offenses.size).to eq(0)
+      expect_no_offenses(<<~RUBY)
+        def up
+          with_lock_retries {}
+        end
+      RUBY
     end
   end
 
-  context 'outside of migration' do
+  context 'when outside of migration' do
     it 'registers no offense' do
-      inspect_source('def change; with_lock_retries {}; end')
-
-      expect(cop.offenses.size).to eq(0)
+      expect_no_offenses(<<~RUBY)
+        def change
+          with_lock_retries {}
+        end
+      RUBY
     end
   end
 end

spec/rubocop/cop/prefer_class_methods_over_module_spec.rb

@@ -2,15 +2,12 @@
 
 require 'fast_spec_helper'
 require 'rubocop'
-require 'rubocop/rspec/support'
 require_relative '../../../rubocop/cop/prefer_class_methods_over_module'
 
 RSpec.describe RuboCop::Cop::PreferClassMethodsOverModule do
-  include CopHelper
-
   subject(:cop) { described_class.new }
 
-  it 'flags violation when using module ClassMethods' do
+  it 'flags violation when using module ClassMethods and corrects', :aggregate_failures do
     expect_offense(<<~RUBY)
       module Foo
         extend ActiveSupport::Concern
@@ -22,6 +19,17 @@ RSpec.describe RuboCop::Cop::PreferClassMethodsOverModule do
         end
       end
     RUBY
+
+    expect_correction(<<~RUBY)
+      module Foo
+        extend ActiveSupport::Concern
+
+        class_methods do
+          def a_class_method
+          end
+        end
+      end
+    RUBY
   end
 
   it "doesn't flag violation when using class_methods" do
@@ -69,30 +77,4 @@ RSpec.describe RuboCop::Cop::PreferClassMethodsOverModule do
       end
     RUBY
   end
-
-  it 'autocorrects ClassMethods into class_methods' do
-    source = <<~RUBY
-      module Foo
-        extend ActiveSupport::Concern
-
-        module ClassMethods
-          def a_class_method
-          end
-        end
-      end
-    RUBY
-    autocorrected = autocorrect_source(source)
-
-    expected_source = <<~RUBY
-      module Foo
-        extend ActiveSupport::Concern
-
-        class_methods do
-          def a_class_method
-          end
-        end
-      end
-    RUBY
-    expect(autocorrected).to eq(expected_source)
-  end
 end

spec/rubocop/cop/put_group_routes_under_scope_spec.rb

@@ -5,8 +5,6 @@ require 'rubocop'
 require_relative '../../../rubocop/cop/put_group_routes_under_scope'
 
 RSpec.describe RuboCop::Cop::PutGroupRoutesUnderScope do
-  include CopHelper
-
   subject(:cop) { described_class.new }
 
   %w[resource resources get post put patch delete].each do |route_method|

spec/rubocop/cop/sidekiq_options_queue_spec.rb

@@ -3,28 +3,19 @@
 require 'fast_spec_helper'
 
 require 'rubocop'
-require 'rubocop/rspec/support'
-
 require_relative '../../../rubocop/cop/sidekiq_options_queue'
 
 RSpec.describe RuboCop::Cop::SidekiqOptionsQueue do
-  include CopHelper
-
   subject(:cop) { described_class.new }
 
   it 'registers an offense when `sidekiq_options` is used with the `queue` option' do
-    inspect_source('sidekiq_options queue: "some_queue"')
-
-    aggregate_failures do
-      expect(cop.offenses.size).to eq(1)
-      expect(cop.offenses.map(&:line)).to eq([1])
-      expect(cop.highlights).to eq(['queue: "some_queue"'])
-    end
+    expect_offense(<<~CODE)
+      sidekiq_options queue: "some_queue"
+                      ^^^^^^^^^^^^^^^^^^^ Do not manually set a queue; `ApplicationWorker` sets one automatically.
+    CODE
   end
 
   it 'does not register an offense when `sidekiq_options` is used with another option' do
-    inspect_source('sidekiq_options retry: false')
-
-    expect(cop.offenses).to be_empty
+    expect_no_offenses('sidekiq_options retry: false')
   end
 end