Merge pull request #27928 from y-yagi/remove_activemodel_testcase_from_lib

Remove `ActiveModel::TestCase` from lib

activemodel/CHANGELOG.md

+*   Remove unused `ActiveModel::TestCase` class.
+
+    *Yuji Yaginuma*
+
 *   Moved DecimalWithoutScale, Text, and UnsignedInteger from Active Model to Active Record
 
     *Iain Beeston*

activemodel/lib/active_model.rb

@@ -42,7 +42,6 @@ module ActiveModel
   autoload :Naming
   autoload :SecurePassword
   autoload :Serialization
-  autoload :TestCase
   autoload :Translation
   autoload :Validations
   autoload :Validator

activemodel/lib/active_model/test_case.rb

-module ActiveModel #:nodoc:
-  class TestCase < ActiveSupport::TestCase #:nodoc:
-  end
-end

activemodel/test/cases/helper.rb

@@ -9,7 +9,7 @@
 require "active_support/testing/autorun"
 require "active_support/testing/method_call_assertions"
 
-class ActiveModel::TestCase
+class ActiveModel::TestCase < ActiveSupport::TestCase
   include ActiveSupport::Testing::MethodCallAssertions
 
   # Skips the current run on Rubinius using Minitest::Assertions#skip