cache_sweeper yields blank output

[#3914 state:open]
Signed-off-by: NJosé Valim <jose.valim@gmail.com>

actionpack/lib/action_controller/caching/sweeping.rb

@@ -57,6 +57,7 @@ class Sweeper < ActiveRecord::Observer #:nodoc:
         def before(controller)
           self.controller = controller
           callback(:before) if controller.perform_caching
+          true # before method from sweeper should always return true
         end
 
         def after(controller)

actionpack/test/abstract_unit.rb

@@ -24,6 +24,9 @@
 require 'action_dispatch'
 require 'active_support/dependencies'
 require 'active_model'
+require 'active_record'
+require 'action_controller/caching'
+require 'action_controller/caching/sweeping'
 
 begin
   require 'ruby-debug'

actionpack/test/controller/filters_test.rb

@@ -445,6 +445,12 @@ def filter_three
 
   end
 
+
+  def test_before_method_of_sweeper_should_always_return_true
+    sweeper =  ActionController::Caching::Sweeper.send(:new)
+    assert sweeper.before(TestController.new)
+  end
+
   def test_non_yielding_around_filters_not_returning_false_do_not_raise
     controller = NonYieldingAroundFilterController.new
     controller.instance_variable_set "@filter_return_value", true