5 files changed, 45 insertions, 26 deletions
diff --git a/actionpack/lib/action_dispatch/http/headers.rb b/actionpack/lib/action_dispatch/http/headers.rb
index 5c3b7245d6..69a934b7cd 100644
--- a/actionpack/lib/action_dispatch/http/headers.rb
+++ b/actionpack/lib/action_dispatch/http/headers.rb
@@ -5,7 +5,7 @@ module ActionDispatch
     #   env     = { "CONTENT_TYPE" => "text/plain", "HTTP_USER_AGENT" => "curl/7.43.0" }
     #   headers = ActionDispatch::Http::Headers.new(env)
     #   headers["Content-Type"] # => "text/plain"
-    #   headers["User-Agent"] # => "curl/7/43/0"
+    #   headers["User-Agent"] # => "curl/7.43.0"
     #
     # Also note that when headers are mapped to CGI-like variables by the Rack
     # server, both dashes and underscores are converted to underscores. This
diff --git a/actionpack/lib/action_dispatch/http/request.rb b/actionpack/lib/action_dispatch/http/request.rb
index 316a9f08b7..b0ed681623 100644
--- a/actionpack/lib/action_dispatch/http/request.rb
+++ b/actionpack/lib/action_dispatch/http/request.rb
@@ -337,7 +337,6 @@ module ActionDispatch
       else
         self.session = {}
       end
-      self.flash = nil
     end
 
     def session=(session) #:nodoc:
diff --git a/actionpack/lib/action_dispatch/middleware/flash.rb b/actionpack/lib/action_dispatch/middleware/flash.rb
index c51dcd542a..06038af571 100644
--- a/actionpack/lib/action_dispatch/middleware/flash.rb
+++ b/actionpack/lib/action_dispatch/middleware/flash.rb
@@ -70,6 +70,11 @@ module ActionDispatch
           session.delete('flash')
         end
       end
+
+      def reset_session # :nodoc
+        super
+        self.flash = nil
+      end
     end
 
     class FlashNow #:nodoc:
diff --git a/actionpack/lib/action_dispatch/routing.rb b/actionpack/lib/action_dispatch/routing.rb
index dcf800b215..79d2f1f13c 100644
--- a/actionpack/lib/action_dispatch/routing.rb
+++ b/actionpack/lib/action_dispatch/routing.rb
@@ -73,14 +73,14 @@ module ActionDispatch
   #   get 'post/:id' => 'posts#show'
   #   post 'post/:id' => 'posts#create_comment'
   #
+  # Now, if you POST to <tt>/posts/:id</tt>, it will route to the <tt>create_comment</tt> action. A GET on the same
+  # URL will route to the <tt>show</tt> action.
+  #
   # If your route needs to respond to more than one HTTP method (or all methods) then using the
   # <tt>:via</tt> option on <tt>match</tt> is preferable.
   #
   #   match 'post/:id' => 'posts#show', via: [:get, :post]
   #
-  # Now, if you POST to <tt>/posts/:id</tt>, it will route to the <tt>create_comment</tt> action. A GET on the same
-  # URL will route to the <tt>show</tt> action.
-  #
   # == Named routes
   #
   # Routes can be named by passing an <tt>:as</tt> option,
diff --git a/actionpack/lib/action_dispatch/testing/integration.rb b/actionpack/lib/action_dispatch/testing/integration.rb
index f4534b4173..60c562d7cd 100644
--- a/actionpack/lib/action_dispatch/testing/integration.rb
+++ b/actionpack/lib/action_dispatch/testing/integration.rb
@@ -735,34 +735,49 @@ module ActionDispatch
   # Consult the Rails Testing Guide for more.
 
   class IntegrationTest < ActiveSupport::TestCase
-    include Integration::Runner
-    include ActionController::TemplateAssertions
-    include ActionDispatch::Routing::UrlFor
+    module UrlOptions
+      extend ActiveSupport::Concern
+      def url_options
+        integration_session.url_options
+      end
+    end
 
-    @@app = nil
+    module Behavior
+      extend ActiveSupport::Concern
 
-    def self.app
-      @@app || ActionDispatch.test_app
-    end
+      include Integration::Runner
+      include ActionController::TemplateAssertions
 
-    def self.app=(app)
-      @@app = app
-    end
+      included do
+        include ActionDispatch::Routing::UrlFor
+        include UrlOptions # don't let UrlFor override the url_options method
+        ActiveSupport.run_load_hooks(:action_dispatch_integration_test, self)
+        @@app = nil
+      end
 
-    def app
-      super || self.class.app
-    end
+      module ClassMethods
+        def app
+          defined?(@@app) ? @@app : ActionDispatch.test_app
+        end
 
-    def url_options
-      integration_session.url_options
-    end
+        def app=(app)
+          @@app = app
+        end
 
-    def document_root_element
-      html_document.root
-    end
+        def register_encoder(*args)
+          Integration::Session::RequestEncoder.register_encoder(*args)
+        end
+      end
 
-    def self.register_encoder(*args)
-      Integration::Session::RequestEncoder.register_encoder(*args)
+      def app
+        super || self.class.app
+      end
+
+      def document_root_element
+        html_document.root
+      end
     end
+
+    include Behavior
   end
 end