Make sure the tests pass in the case closer to described in #8195

Conflicts:
	activerecord/test/models/bulb.rb
	activerecord/test/schema/schema.rb

activerecord/test/cases/base_test.rb

@@ -23,6 +23,8 @@
 require 'models/joke'
 require 'models/bulb'
 require 'models/bird'
+require 'models/car'
+require 'models/bulb'
 require 'rexml/document'
 require 'active_support/core_ext/exception'
 
@@ -1442,6 +1444,16 @@ def test_cache_key_format_for_existing_record_with_updated_at
     assert_equal "developers/#{dev.id}-#{dev.updated_at.utc.to_s(:nsec)}", dev.cache_key
   end
 
+  def test_cache_key_changes_when_child_touched
+    car = Car.create
+    Bulb.create(car: car)
+
+    key = car.cache_key
+    car.bulb.touch
+    car.reload
+    assert_not_equal key, car.cache_key
+  end
+
   def test_cache_key_format_for_existing_record_with_nil_updated_at
     dev = Developer.first
     dev.update_columns(updated_at: nil)

activerecord/test/cases/cache_key_test.rb

-require "cases/helper"
-require "models/invoice"
-require "models/line_item"
-
-class CacheKeyTest < ActiveRecord::TestCase
-  def setup
-    @invoice = Invoice.create
-    LineItem.create(invoice: @invoice)
-    @invoice.reload
-  end
-
-  def test_cache_key_changes_when_child_touched
-    key = @invoice.cache_key
-    @invoice.line_items[0].touch
-    @invoice.reload
-    assert_not_equal key, @invoice.cache_key
-  end
-end

activerecord/test/models/bulb.rb

 class Bulb < ActiveRecord::Base
   default_scope { where(:name => 'defaulty') }
-  belongs_to :car
+  belongs_to :car, :touch => true
 
   attr_reader :scope_after_initialize, :attributes_after_initialize
 

activerecord/test/schema/schema.rb

@@ -115,6 +115,7 @@ def create_table(*args, &block)
     t.integer :engines_count
     t.integer :wheels_count
     t.column :lock_version, :integer, :null => false, :default => 0
+    t.timestamps
   end
 
   create_table :categories, :force => true do |t|