Add cookieless A/A test

app/assets/javascripts/modules/cookieless-tracker.js

@@ -0,0 +1,116 @@
+window.GOVUK = window.GOVUK || {}
+window.GOVUK.Modules = window.GOVUK.Modules || {};
+
+(function (Modules) {
+  var CookielessTracker = function (trackingId, fieldsObject) {
+    var trackerName = fieldsObject.name + '.'
+
+    function configureProfile () {
+      // https://developers.google.com/analytics/devguides/collection/analyticsjs/command-queue-reference#create
+      sendToGa('create', trackingId, fieldsObject)
+    }
+
+    function anonymizeIp () {
+      // https://developers.google.com/analytics/devguides/collection/analyticsjs/advanced#anonymizeip
+      sendToGa(trackerName + 'set', 'anonymizeIp', true)
+    }
+
+    function disableAdFeatures () {
+      // https://developers.google.com/analytics/devguides/collection/analyticsjs/field-reference#allowAdFeatures
+      sendToGa(trackerName + 'set', 'allowAdFeatures', false)
+    }
+
+    function stripTitlePII () {
+      sendToGa(trackerName + 'set', 'title', '')
+    }
+
+    function stripLocationPII () {
+      sendToGa(trackerName + 'set', 'location', '')
+    }
+
+    function load () {
+      /* eslint-disable */
+      (function (i, s, o, g, r, a, m) { i['GoogleAnalyticsObject'] = r; i[r] = i[r] || function () {
+        (i[r].q = i[r].q || []).push(arguments) }, i[r].l = 1 * new Date(); a = s.createElement(o),
+        m = s.getElementsByTagName(o)[0]; a.async = 1; a.src = g; m.parentNode.insertBefore(a, m)
+      })(window, document, 'script', 'https://www.google-analytics.com/analytics.js', 'ga')
+      /* eslint-enable */
+    }
+
+    // Support legacy cookieDomain param
+    if (typeof fieldsObject === 'string') {
+      fieldsObject = { cookieDomain: fieldsObject }
+    }
+
+    load()
+    configureProfile()
+    anonymizeIp()
+    disableAdFeatures()
+    stripTitlePII()
+    stripLocationPII()
+  }
+
+  CookielessTracker.load = function () {
+    /* eslint-disable */
+    (function (i, s, o, g, r, a, m) { i['GoogleAnalyticsObject'] = r; i[r] = i[r] || function () {
+      (i[r].q = i[r].q || []).push(arguments) }, i[r].l = 1 * new Date(); a = s.createElement(o),
+      m = s.getElementsByTagName(o)[0]; a.async = 1; a.src = g; m.parentNode.insertBefore(a, m)
+    })(window, document, 'script', 'https://www.google-analytics.com/analytics.js', 'ga')
+    /* eslint-enable */
+  }
+
+  // https://developers.google.com/analytics/devguides/collection/analyticsjs/events
+  CookielessTracker.prototype.trackEvent = function (category, action, options) {
+    options = options || {}
+    var value
+    var trackerName = ''
+    var evt = {
+      hitType: 'event',
+      eventCategory: category,
+      eventAction: action
+    }
+
+    // Label is optional
+    if (typeof options.label === 'string') {
+      evt.eventLabel = options.label
+      delete options.label
+    }
+
+    // Value is optional, but when used must be an
+    // integer, otherwise the event will be invalid
+    // and not logged
+    if (options.value || options.value === 0) {
+      value = parseInt(options.value, 10)
+      if (typeof value === 'number' && !isNaN(value)) {
+        options.eventValue = value
+      }
+      delete options.value
+    }
+
+    // trackerName is optional
+    if (typeof options.trackerName === 'string') {
+      trackerName = options.trackerName + '.'
+      delete options.trackerName
+    }
+
+    // Prevents an event from affecting bounce rate
+    // https://developers.google.com/analytics/devguides/collection/analyticsjs/events#implementation
+    if (options.nonInteraction) {
+      options.nonInteraction = 1
+    }
+
+    if (typeof options === 'object') {
+      $.extend(evt, options)
+    }
+
+    sendToGa(trackerName + 'send', evt)
+  }
+
+  function sendToGa () {
+    if (typeof window.ga === 'function') {
+      window.ga.apply(window, arguments)
+    }
+  }
+
+  Modules.CookielessTracker = CookielessTracker
+})(window.GOVUK.Modules)

app/assets/javascripts/modules/track-variant.js

@@ -0,0 +1,32 @@
+window.GOVUK.Modules = window.GOVUK.Modules || {};
+
+(function (Modules) {
+  'use strict'
+
+  Modules.TrackVariant = function () {
+    this.start = function ($element) {
+      var element = $element[0]
+
+      if (window.GOVUK.cookie('cookies_preferences_set') !== 'true') {
+        var variant = element.getAttribute('content')
+
+        if (variant === undefined) {
+          return
+        }
+
+        var cookielessTracker = new GOVUK.Modules.CookielessTracker('UA-26179049-29', {
+          name: 'CookielessTracker',
+          storage: 'none',
+          clientId: '0'
+        })
+
+        cookielessTracker.trackEvent('cookieless', 'hit', {
+          trackerName: 'CookielessTracker',
+          label: variant,
+          javaEnabled: false,
+          language: ''
+        })
+      }
+    }
+  }
+})(window.GOVUK.Modules)

app/controllers/application_controller.rb

@@ -3,6 +3,8 @@ class ApplicationController < ActionController::Base
   # For APIs, you may want to use :null_session instead.
   protect_from_forgery except: :service_sign_in_options
 
+  include CookielessTestable
+
   if ENV["BASIC_AUTH_USERNAME"]
     http_basic_authenticate_with(
       name: ENV.fetch("BASIC_AUTH_USERNAME"),

app/controllers/concerns/cookieless_testable.rb

@@ -0,0 +1,31 @@
+module CookielessTestable
+  extend ActiveSupport::Concern
+
+  CUSTOM_DIMENSION = 49
+
+  def self.included(base)
+    base.helper_method(
+      :cookieless_variant,
+    )
+    base.after_action :set_test_response_header
+  end
+
+  def cookieless_variant
+    @cookieless_variant ||= cookieless_test.requested_variant(request.headers)
+  end
+
+private
+
+  def cookieless_test
+    @cookieless_test ||= GovukAbTesting::AbTest.new(
+      "CookielessAATest",
+      dimension: CUSTOM_DIMENSION,
+      allowed_variants: %w[A B Z],
+      control_variant: "Z",
+    )
+  end
+
+  def set_test_response_header
+    cookieless_variant.configure_response(response)
+  end
+end

app/views/layouts/application.html.erb

@@ -26,6 +26,11 @@
   <% if @content_item.description %>
     <meta name="description" content="<%= strip_tags(@content_item.description) %>" />
   <% end %>
+
+  <%= cookieless_variant.analytics_meta_tag.html_safe %>
+  <% unless cookieless_variant.variant?('Z') %>
+    <meta name="Cookieless-Variant" content="<%= cookieless_variant.variant_name %>" data-module="track-variant">
+  <% end %>
 
   <%= yield :extra_head_content %>
 </head>

spec/javascripts/track-variant-spec.js

@@ -0,0 +1,61 @@
+describe('Test variant tracker', function () {
+  'use strict'
+
+  var tracker,
+    element,
+    FakeCookielessTracker,
+    gaSpy
+
+  beforeEach(function () {
+    GOVUK.cookie('cookies_preferences_set', null)
+    gaSpy = jasmine.createSpyObj('initGa', ['send'])
+
+    FakeCookielessTracker = function (trackingId, fieldsObject) {}
+    FakeCookielessTracker.prototype.trackEvent = function (category, action, options) {
+      gaSpy.send(category, action, options)
+    }
+
+    GOVUK.Modules.CookielessTracker = FakeCookielessTracker
+
+    tracker = new GOVUK.Modules.TrackVariant()
+  })
+
+  afterEach(function () {
+    GOVUK.Modules.CookielessTracker = null
+  })
+
+  it('tracks A variant', function () {
+    element = $('<meta name="Cookieless-Variant" content="A" data-module="track-variant">')
+
+    tracker.start(element)
+
+    expect(gaSpy.send).toHaveBeenCalledWith('cookieless', 'hit', {
+      trackerName: 'CookielessTracker',
+      label: 'A',
+      javaEnabled: false,
+      language: ''
+    })
+  })
+
+  it('tracks B variant', function () {
+    element = $('<meta name="Cookieless-Variant" content="B" data-module="track-variant">')
+
+    tracker.start(element)
+
+    expect(gaSpy.send).toHaveBeenCalledWith('cookieless', 'hit', {
+      trackerName: 'CookielessTracker',
+      label: 'B',
+      javaEnabled: false,
+      language: ''
+    })
+  })
+
+  it('does not track variant if cookie is set', function () {
+    GOVUK.cookie('cookies_preferences_set', true)
+    element = $('<meta name="Cookieless-Variant" content="Z" data-module="track-variant">')
+
+    tracker.start(element)
+
+    expect(gaSpy.send).not.toHaveBeenCalled()
+  })
+})

test/controllers/content_items_controller_test.rb

@@ -385,6 +385,26 @@ class ContentItemsControllerTest < ActionController::TestCase
     assert_select ".gem-c-contextual-footer", false
   end
 
+  %w[A B].each do |test_variant|
+    test "record cookieless hit when in variant #{test_variant}" do
+      with_variant CookielessAATest: test_variant.to_s do
+        content_item = content_store_has_schema_example("case_study", "case_study")
+
+        get :show, params: { path: path_for(content_item) }
+        assert_select "meta[data-module=track-variant][content=#{test_variant}]"
+      end
+    end
+  end
+
+  test "not record cookieless hit when in variant Z" do
+    with_variant CookielessAATest: "Z" do
+      content_item = content_store_has_schema_example("case_study", "case_study")
+
+      get :show, params: { path: path_for(content_item) }
+      assert_select "meta[data-module=track-variant]", false
+    end
+  end
+
   def path_for(content_item, locale = nil)
     base_path = content_item["base_path"].sub(/^\//, "")
     base_path.gsub!(/\.#{locale}$/, "") if locale