whitelist allowed file types for custom favicons

app/uploaders/favicon_uploader.rb

@@ -33,6 +33,10 @@ class FaviconUploader < AttachmentUploader
     end
   end
 
+  def extension_whitelist
+    UploaderHelper::IMAGE_EXT
+  end
+
   private
 
   def status_favicon(status_name)

config/locales/carrierwave.en.yml

+en:
+  errors:
+    messages:
+      carrierwave_processing_error: failed to be processed
+      carrierwave_integrity_error: is not of an allowed file type
+      carrierwave_download_error: could not be downloaded
+      extension_whitelist_error: "You are not allowed to upload %{extension} files, allowed types: %{allowed_types}"
+      extension_blacklist_error: "You are not allowed to upload %{extension} files, prohibited types: %{prohibited_types}"
+      content_type_whitelist_error: "You are not allowed to upload %{content_type} files"
+      content_type_blacklist_error: "You are not allowed to upload %{content_type} files"
+      rmagick_processing_error: "Failed to manipulate with rmagick, maybe it is not an image?"
+      mini_magick_processing_error: "Failed to manipulate with MiniMagick, maybe it is not an image? Original Error: %{e}"
+      min_size_error: "File size should be greater than %{min_size}"
+      max_size_error: "File size should be less than %{max_size}"

spec/features/admin/admin_appearance_spec.rb

@@ -108,6 +108,12 @@ feature 'Admin Appearance' do
     expect(page).not_to have_css('//img[data-src$="/status_skipped_dk.ico"]')
     expect(page).not_to have_css('//img[data-src$="/status_success_dk.ico"]')
     expect(page).not_to have_css('//img[data-src$="/status_warning_dk.ico"]')
+
+    # allowed file types
+    attach_file(:appearance_favicon, Rails.root.join('spec', 'fixtures', 'sanitized.svg'))
+    click_button 'Save'
+
+    expect(page).to have_content 'Favicon You are not allowed to upload "svg" files, allowed types: png, jpg, jpeg, gif, bmp, tiff, ico'
   end
 
   def expect_custom_sign_in_appearance(appearance)