Fix ensure_valid_locale_persisted and change public interface of service

app/controllers/spree/user_sessions_controller.rb

@@ -52,9 +52,10 @@ module Spree
 
     def ensure_valid_locale_persisted
       # When creating a new user session we have to wait until after a successful
-      # login to be able to persist a locale on the current user
+      # login to be able to persist a selected locale on the current user
 
-      UserLocaleSetter.ensure_valid_locale_persisted(spree_current_user)
+      UserLocaleSetter.new(spree_current_user, params[:locale], cookies).
+        ensure_valid_locale_persisted
     end
   end
 end

app/helpers/i18n_helper.rb

@@ -1,6 +1,6 @@
 module I18nHelper
   def set_locale
-    UserLocaleSetter.new(spree_current_user, params[:locale], cookies).call
+    UserLocaleSetter.new(spree_current_user, params[:locale], cookies).set_locale
   end
 
   def valid_locale(user)

app/services/user_locale_setter.rb

@@ -7,17 +7,17 @@ class UserLocaleSetter
     @cookies = cookies
   end
 
-  def call
+  def set_locale
     save_locale_from_params
     save_locale_from_cookies
 
     I18n.locale = valid_current_locale
   end
 
-  def self.ensure_valid_locale_persisted(user)
-    return unless user && !available_locale?(user.locale)
+  def ensure_valid_locale_persisted
+    return unless current_user && !available_locale?(current_user.locale)
 
-    user.update!(locale: I18n.default_locale)
+    current_user.update!(locale: valid_current_locale)
   end
 
   def self.valid_locale_for_user(user)

spec/features/consumer/authentication_spec.rb

@@ -175,7 +175,7 @@ feature "Authentication", js: true do
           user.update!(locale: nil)
         end
 
-        xit "logs in successfully and uses the locale from cookies" do
+        it "logs in successfully and uses the locale from cookies" do
           page.driver.browser.manage.add_cookie(name: 'locale', value: 'es')
 
           fill_in_and_submit_login_form(user)