Added a step to compare actual images

features/rails.feature

@@ -31,3 +31,4 @@ Feature: Running paperclip in a Rails app
     And I press "Submit"
     Then I should see "Name: something"
     And I should see an image with a path of "/system/avatars/1/original/5k.png"
+    And the file at "/system/avatars/1/original/5k.png" is the same as "test/fixtures/5k.png"

features/step_definitions/html_steps.rb

 Then %r{I should see an image with a path of "([^"]*)"} do |path|
   page.should have_css("img[src^='#{path}']")
 end
+
+Then %r{^the file at "([^"]*)" is the same as "([^"]*)"$} do |web_file, path|
+  visit(web_file)
+  page.body.should == IO.read(path)
+end

features/step_definitions/rails_steps.rb

@@ -24,7 +24,7 @@ end
 When %r{the rails application is running} do
   Dir.chdir(CUC_RAILS_ROOT) do
     require "config/environment"
-    Capybara.app = ActionController::Dispatcher.new
+    require "capybara/rails"
   end
 end