Fixed Function + Test based on MR

app/helpers/icons_helper.rb

 module IconsHelper
   extend self
-  include Gitlab::CurrentSettings
   include FontAwesome::Rails::IconHelper
 
   # Creates an icon tag given icon name(s) and possible icon modifiers.
@@ -27,14 +26,14 @@ module IconsHelper
   def sprite_icon_path
     # SVG Sprites currently don't work across domains, so in the case of a CDN
     # we have to set the current path deliberately to prevent addition of asset_host
-    sprite_base_url = ActionController::Base.asset_host.present? ? Gitlab.config.gitlab.url : nil
+    sprite_base_url = Gitlab.config.gitlab.url if ActionController::Base.asset_host
     ActionController::Base.helpers.image_path('icons.svg', host: sprite_base_url)
   end
 
   def sprite_icon(icon_name, size: nil, css_class: nil)
     css_classes = size ? "s#{size}" : ""
     css_classes << " #{css_class}" unless css_class.blank?
-    content_tag(:svg, content_tag(:use, "", { "xlink:href" => "#{sprite_icon_path()}##{icon_name}" } ), class: css_classes.empty? ? nil : css_classes)
+    content_tag(:svg, content_tag(:use, "", { "xlink:href" => "#{sprite_icon_path}##{icon_name}" } ), class: css_classes.empty? ? nil : css_classes)
   end
 
   def audit_icon(names, options = {})

spec/helpers/icons_helper_spec.rb

 require 'spec_helper'
 
 describe IconsHelper do
+  let(:icons_path) { ActionController::Base.helpers.image_path("icons.svg") }
+
   describe 'icon' do
     it 'returns aria-hidden by default' do
       star = icon('star')
@@ -18,8 +20,8 @@ describe IconsHelper do
 
   describe 'sprite_icon_path' do
     it 'returns relative path' do
-      expect(sprite_icon_path())
-        .to eq icons_path()
+      expect(sprite_icon_path)
+        .to eq icons_path
     end
 
     context 'when an asset_host is set in the config it will return an absolute local URL' do
@@ -41,17 +43,17 @@ describe IconsHelper do
 
     it 'returns svg icon html' do
       expect(sprite_icon(icon_name).to_s)
-        .to eq "<svg><use xlink:href=\"#{icons_path()}##{icon_name}\"></use></svg>"
+        .to eq "<svg><use xlink:href=\"#{icons_path}##{icon_name}\"></use></svg>"
     end
 
     it 'returns svg icon html + size classes' do
       expect(sprite_icon(icon_name, size: 72).to_s)
-        .to eq "<svg class=\"s72\"><use xlink:href=\"#{icons_path()}##{icon_name}\"></use></svg>"
+        .to eq "<svg class=\"s72\"><use xlink:href=\"#{icons_path}##{icon_name}\"></use></svg>"
     end
 
     it 'returns svg icon html + size classes + additional class' do
       expect(sprite_icon(icon_name, size: 72, css_class: 'icon-danger').to_s)
-        .to eq "<svg class=\"s72 icon-danger\"><use xlink:href=\"#{icons_path()}#{icon_name}\"></use></svg>"
+        .to eq "<svg class=\"s72 icon-danger\"><use xlink:href=\"#{icons_path}##{icon_name}\"></use></svg>"
     end
   end
 
@@ -160,8 +162,4 @@ describe IconsHelper do
       expect(file_type_icon_class('file', 0, 'CHANGELOG')).to eq 'file-text-o'
     end
   end
-
-  def icons_path
-    ActionController::Base.helpers.image_path("icons.svg")
-  end
 end