Merge remote branch 'rails/master' into identity_map

Conflicts:
	activerecord/lib/active_record/associations/association_proxy.rb
	activerecord/lib/active_record/autosave_association.rb
	activerecord/lib/active_record/base.rb
	activerecord/lib/active_record/persistence.rb

1 files changed, 5 insertions, 2 deletions

diff --git a/actionmailer/lib/action_mailer/test_case.rb b/actionmailer/lib/action_mailer/test_case.rb
index f4d1bb59f1..63e18147f6 100644
--- a/actionmailer/lib/action_mailer/test_case.rb
+++ b/actionmailer/lib/action_mailer/test_case.rb
@@ -1,3 +1,5 @@
+require 'active_support/core_ext/class/attribute'
+
 module ActionMailer
   class NonInferrableMailerError < ::StandardError
     def initialize(name)
@@ -15,11 +17,11 @@ module ActionMailer
 
       module ClassMethods
         def tests(mailer)
-          write_inheritable_attribute(:mailer_class, mailer)
+          self._mailer_class = mailer
         end
 
         def mailer_class
-          if mailer = read_inheritable_attribute(:mailer_class)
+          if mailer = self._mailer_class
             mailer
           else
             tests determine_default_mailer(name)
@@ -65,6 +67,7 @@ module ActionMailer
       end
 
       included do
+        class_attribute :_mailer_class
         setup :initialize_test_deliveries
         setup :set_expected_mail
       end