3 files changed, 30 insertions, 18 deletions
diff --git a/actionmailer/lib/action_mailer/async.rb b/actionmailer/lib/action_mailer/async.rb
index 6fcc94d50e..d7c34c1a7b 100644
--- a/actionmailer/lib/action_mailer/async.rb
+++ b/actionmailer/lib/action_mailer/async.rb
@@ -1,22 +1,23 @@
 require 'delegate'
 
 module ActionMailer::Async
-  def self.included(base)
-    base.extend(ClassMethods)
+  def method_missing(method_name, *args)
+    if action_methods.include?(method_name.to_s)
+      QueuedMessage.new(queue, self, method_name, *args)
+    else
+      super
+    end
   end
 
-  module ClassMethods
-    def method_missing(method_name, *args)
-      if action_methods.include?(method_name.to_s)
-        QueuedMessage.new(self, method_name, *args)
-      else
-        super
-      end
-    end
+  def queue
+    Rails.queue
   end
 
   class QueuedMessage < ::Delegator
-    def initialize(mailer_class, method_name, *args)
+    attr_reader :queue
+
+    def initialize(queue, mailer_class, method_name, *args)
+      @queue        = queue
       @mailer_class = mailer_class
       @method_name  = method_name
       @args         = args
@@ -37,7 +38,7 @@ module ActionMailer::Async
       if force
         run
       else
-        Rails.queue << self
+        @queue << self
       end
     end
   end
diff --git a/actionmailer/lib/action_mailer/base.rb b/actionmailer/lib/action_mailer/base.rb
index 5686e78dfc..1f6c00ce11 100644
--- a/actionmailer/lib/action_mailer/base.rb
+++ b/actionmailer/lib/action_mailer/base.rb
@@ -460,7 +460,7 @@ module ActionMailer #:nodoc:
       def async=(truth)
         if truth
           require 'action_mailer/async'
-          include ActionMailer::Async
+          extend ActionMailer::Async
         end
       end
 
diff --git a/actionmailer/test/base_test.rb b/actionmailer/test/base_test.rb
index 908ce719b5..f1988a8230 100644
--- a/actionmailer/test/base_test.rb
+++ b/actionmailer/test/base_test.rb
@@ -422,22 +422,33 @@ class BaseTest < ActiveSupport::TestCase
     assert_equal(1, BaseMailer.deliveries.length)
   end
 
+  def stub_queue klass, queue
+    Class.new(klass) {
+      extend Module.new {
+        define_method :queue do
+          queue
+        end
+      }
+    }
+  end
+
   test "delivering message asynchronously" do
-    Rails.stubs(:queue).returns(Rails::Queueing::TestQueue.new)
+    testing_queue = Rails::Queueing::TestQueue.new
     AsyncMailer.delivery_method = :test
     AsyncMailer.deliveries.clear
-    AsyncMailer.welcome.deliver
+    stub_queue(AsyncMailer, testing_queue).welcome.deliver
     assert_equal(0, AsyncMailer.deliveries.length)
-    Rails.queue.drain
+    testing_queue.drain
     assert_equal(1, AsyncMailer.deliveries.length)
   end
 
   test "forcing message delivery despite asynchronous" do
-    Rails.stubs(:queue).returns(Rails::Queueing::TestQueue.new)
+    testing_queue = Rails::Queueing::TestQueue.new
     AsyncMailer.delivery_method = :test
     AsyncMailer.deliveries.clear
-    AsyncMailer.welcome.deliver(true)
+    stub_queue(AsyncMailer, testing_queue).welcome.deliver(true)
     assert_equal(1, AsyncMailer.deliveries.length)
+    assert_predicate testing_queue, :empty?
   end
 
   test "calling deliver, ActionMailer should yield back to mail to let it call :do_delivery on itself" do