Internationalization of resource_name in DeviseHelper#devise_error_messages!

app/helpers/devise_helper.rb

@@ -11,7 +11,7 @@ module DeviseHelper
     messages = resource.errors.full_messages.map { |msg| content_tag(:li, msg) }.join
     sentence = I18n.t("errors.messages.not_saved",
                       :count => resource.errors.count,
-                      :resource => resource_name)
+                      :resource => resource.class.model_name.human.downcase)
 
     html = <<-HTML
     <div id="error_explanation">

test/helpers/devise_helper_test.rb

@@ -0,0 +1,41 @@
+require 'test_helper'
+
+class DeviseHelperTest < ActionController::IntegrationTest
+  setup do
+    I18n.backend.store_translations :fr,
+    {
+      :errors => { :messages => { :not_saved => {
+        :one => "Erreur lors de l'enregistrement de '%{resource}': 1 erreur.",
+        :other => "Erreur lors de l'enregistrement de '%{resource}': %{count} erreurs."
+      } } },
+      :activerecord => { :models => { :user => "utilisateur" } }
+    }
+  
+    I18n.locale = 'fr'
+  end
+  
+  test 'test errors.messages.not_saved with single error from i18n' do
+    
+    get new_user_registration_path
+    
+    fill_in 'password', :with => 'new_user123'
+    fill_in 'password confirmation', :with => 'new_user123'
+    click_button 'Sign up'
+
+    assert_have_selector '#error_explanation'
+    assert_contain "Erreur lors de l'enregistrement de 'utilisateur': 1 erreur"
+  end
+  
+  test 'test errors.messages.not_saved with multiple errors from i18n' do
+    get new_user_registration_path
+    
+    fill_in 'email', :with => 'invalid_email'
+    fill_in 'password', :with => 'new_user123'
+    fill_in 'password confirmation', :with => 'new_user321'
+    click_button 'Sign up'
+
+    assert_have_selector '#error_explanation'
+    assert_contain "Erreur lors de l'enregistrement de 'utilisateur': 2 erreurs"
+  end
+  
+end