Properly deprecate #pending from AS::TestCase

Check https://github.com/rails/rails/pull/4575#issuecomment-5765575.

activesupport/CHANGELOG.md

@@ -1,5 +1,7 @@
 ## Rails 4.0.0 (unreleased) ##
 
+*   Deprecate `ActiveSupport::TestCase#pending` method, use `skip` from MiniTest instead. *Carlos Antonio da Silva*
+
 *   `XmlMini.with_backend` now may be safely used with threads:
 
         Thread.new do

activesupport/lib/active_support/testing/pending.rb

@@ -1,20 +1,14 @@
-# Some code from jeremymcanally's "pending"
-# https://github.com/jeremymcanally/pending/tree/master
+require 'active_support/deprecation'
 
 module ActiveSupport
   module Testing
     module Pending
-
       unless defined?(Spec)
-
-        @@pending_cases = []
-        @@at_exit = false
-
         def pending(description = "", &block)
+          ActiveSupport::Deprecation.warn("#pending is deprecated and will be removed in Rails 4.1, please use #skip instead.")
           skip(description.blank? ? nil : description)
         end
       end
-
     end
   end
 end

activesupport/test/test_case_test.rb

@@ -108,5 +108,11 @@ module ActiveSupport
       test = tc.new test_name
       assert_raises(Interrupt) { test.run fr }
     end
+
+    def test_pending_deprecation
+      assert_deprecated do
+        pending "should use #skip instead"
+      end
+    end
   end
 end