Publish worldwide corporate information about pages as redirects

Worldwide corporate information about pages aren't rendered, instead they are
surfaced in the body of the owning worldwide organisation.

There have been various attempts to devise a strategy for these pages.
Currently, they are published with the `schema_name` of
`placeholder_corporate_information_page` at the path
`world/organisation/:organisation_id/about/about`.

Unfortunately, anywhere in Whitehall that links to the base path of these pages
now 404s. Instead, we should redirect to the worldwide organisation itself.

This:
- Updates the base path of worldwide corporate
  information pages to
  `world/organisation/:organisation_id/about` to
  match the non-worldwide
  organisation corporate information pages.
- Adds a generic presenter for a redirect.
- Publishes worldwide corporate information pages as
  redirects.

This means any worldwide corporate information about pages will now live at
`world/organisation/:organisation_id/about`. When we republish these content
items, Pulishing API will create additional redirect from each
`world/organisation/:organisation_id/about/about` to
`world/organisation/:organisation_id/about` as well.

app/models/corporate_information_page.rb

@@ -110,6 +110,12 @@ def sorted_organisations
     organisations
   end
 
+  def api_presenter_redirect_to
+    raise "only worldwide about pages should redirect" unless about_page? && worldwide_organisation.present?
+
+    worldwide_organisation.public_path(locale: I18n.locale)
+  end
+
   def self.for_slug(slug)
     if (type = CorporateInformationPageType.find(slug))
       find_by(corporate_information_page_type_id: type.id)
@@ -175,8 +181,7 @@ def base_path
     return if owning_organisation.blank?
 
     url = owning_organisation.base_path + "/about/#{slug}"
-    url.gsub!("/about/about", "/about") if organisation.present?
-    url
+    url.gsub("/about/about", "/about")
   end
 
 private

app/presenters/publishing_api/redirect_presenter.rb

@@ -0,0 +1,39 @@
+module PublishingApi
+  class RedirectPresenter
+    attr_accessor :item, :update_type
+
+    def initialize(item, update_type: nil)
+      self.item = item
+      self.update_type = update_type || "major"
+    end
+
+    delegate :content_id, to: :item
+
+    def content
+      {
+        title: nil,
+        locale: I18n.locale.to_s,
+        base_path: item.public_path(locale: I18n.locale),
+        document_type: "redirect",
+        schema_name: "redirect",
+        redirects:,
+        publishing_app: Whitehall::PublishingApp::WHITEHALL,
+        update_type:,
+      }
+    end
+
+    def links
+      {}
+    end
+
+  private
+
+    def redirects
+      [{
+        path: item.public_path(locale: I18n.locale),
+        type: "exact",
+        destination: item.api_presenter_redirect_to,
+      }]
+    end
+  end
+end

app/presenters/publishing_api_presenters.rb

@@ -64,12 +64,12 @@ def presenter_class_for_edition(edition)
       when Consultation
         PublishingApi::ConsultationPresenter
       when CorporateInformationPage
-        if edition.worldwide_organisation.present? && !edition.about_page?
+        if edition.worldwide_organisation.present? && edition.about_page?
+          PublishingApi::RedirectPresenter
+        elsif edition.worldwide_organisation.present?
           PublishingApi::WorldwideCorporateInformationPagePresenter
-        elsif edition.organisation.present?
-          PublishingApi::CorporateInformationPagePresenter
         else
-          FALLBACK_EDITION_PRESENTER
+          PublishingApi::CorporateInformationPagePresenter
         end
       when ::DetailedGuide
         PublishingApi::DetailedGuidePresenter

test/unit/app/models/corporate_information_page_test.rb

@@ -51,6 +51,17 @@ class CorporateInformationPageTest < ActiveSupport::TestCase
     assert_equal "/government/organisations/#{organisation.name}/about", corporate_information_page.base_path
   end
 
+  test "base_path appends /about to the associated Worldwide Organisation base_path when about page" do
+    worldwide_organisation = create(:worldwide_organisation)
+    corporate_information_page = create(
+      :about_corporate_information_page,
+      organisation: nil,
+      worldwide_organisation:,
+    )
+
+    assert_equal "/world/organisations/#{worldwide_organisation.name}/about", corporate_information_page.base_path
+  end
+
   test "base_path appends Corporate Information Page path to the associated WorldwideOrganisation base_path" do
     worldwide_organisation = create(:worldwide_organisation)
     corporate_information_page = create(
@@ -62,15 +73,25 @@ class CorporateInformationPageTest < ActiveSupport::TestCase
     assert_equal "/world/organisations/#{worldwide_organisation.name}/about/#{corporate_information_page.slug}", corporate_information_page.base_path
   end
 
-  test "#base_path appends /about/about to WorldwideOrganisation base_path when about page" do
+  test "api_presenter_redirect_to returns the base_path of the owning Worldwide Organisation for about us pages" do
     worldwide_organisation = create(:worldwide_organisation)
     corporate_information_page = create(
       :about_corporate_information_page,
       organisation: nil,
       worldwide_organisation:,
     )
 
-    assert_equal "/world/organisations/#{worldwide_organisation.name}/about/about", corporate_information_page.base_path
+    assert_equal "/world/organisations/#{worldwide_organisation.name}", corporate_information_page.api_presenter_redirect_to
+  end
+
+  test "api_presenter_redirect_to returns a #{RuntimeError} when not a Worldwide Organisation about page" do
+    organisation = create(:organisation)
+    corporate_information_page = create(
+      :about_corporate_information_page,
+      organisation:,
+    )
+
+    assert_raises(RuntimeError, "only worldwide about pages should redirect") { corporate_information_page.api_presenter_redirect_to }
   end
 
   test "republishes owning organisation after commit when present" do

test/unit/app/presenters/publishing_api/redirect_presenter_test.rb

@@ -0,0 +1,73 @@
+require "test_helper"
+
+class PublishingApi::RedirectPresenterTest < ActiveSupport::TestCase
+  def present(...)
+    PublishingApi::RedirectPresenter.new(...)
+  end
+
+  test "presents an item as a redirect to the publishing API" do
+    item = create(
+      :corporate_information_page,
+      :published,
+      organisation: nil,
+      worldwide_organisation: create(:worldwide_organisation),
+      corporate_information_page_type_id: CorporateInformationPageType::AboutUs.id,
+    )
+
+    expected_hash = {
+      title: nil,
+      locale: "en",
+      publishing_app: "whitehall",
+      redirects: [{
+        path: item.base_path,
+        type: "exact",
+        destination: item.api_presenter_redirect_to,
+      }],
+      update_type: "major",
+      base_path: item.base_path,
+      document_type: "redirect",
+      schema_name: "redirect",
+    }
+
+    presented_item = present(item)
+
+    assert_equal item.content_id, presented_item.content_id
+    assert_equal expected_hash, presented_item.content
+    assert_equal presented_item.links, {}
+    assert_valid_against_publisher_schema(presented_item.content, "redirect")
+  end
+
+  test "presents an item as a redirect to publishing API when translated" do
+    I18n.with_locale(:ar) do
+      item = create(
+        :corporate_information_page,
+        :published,
+        organisation: nil,
+        worldwide_organisation: create(:worldwide_organisation),
+        corporate_information_page_type_id: CorporateInformationPageType::AboutUs.id,
+      )
+
+      expected_hash = {
+        title: nil,
+        locale: "ar",
+        publishing_app: "whitehall",
+        redirects: [{
+          path: item.public_path(locale: I18n.locale),
+          type: "exact",
+          destination: item.api_presenter_redirect_to,
+        }],
+        update_type: "major",
+        base_path: item.public_path(locale: I18n.locale),
+        document_type: "redirect",
+        schema_name: "redirect",
+      }
+
+      presented_item = present(item)
+
+      assert_equal item.content_id, presented_item.content_id
+      assert_equal expected_hash, presented_item.content
+      assert_equal presented_item.links, {}
+      assert_valid_against_publisher_schema(presented_item.content, "redirect")
+    end
+  end
+end

test/unit/app/presenters/publishing_api_presenters_test.rb

@@ -149,7 +149,7 @@ class PublishingApiPresentersTest < ActiveSupport::TestCase
     )
   end
 
-  test ".presenter_for returns a GenericEditionPresenter for an " \
+  test ".presenter_for returns a RedirectPresenter for an " \
     "AboutUs CorporateInformationPage belonging to an WorldwideOrganisation" do
     presenter = PublishingApiPresenters
       .presenter_for(
@@ -162,7 +162,7 @@ class PublishingApiPresentersTest < ActiveSupport::TestCase
       )
 
     assert_equal(
-      PublishingApi::GenericEditionPresenter,
+      PublishingApi::RedirectPresenter,
       presenter.class,
     )
   end