Add link to preview draft and published versions

app/helpers/paths_helper.rb

@@ -13,6 +13,20 @@ def preview_edition_path(edition)
     path
   end
 
+  def preview_homepage_path(edition)
+    path = "#{preview_url(edition)}" # rubocop:disable Style/RedundantInterpolation
+
+    if should_have_auth_bypass_id?(edition)
+      path << "?token=#{jwt_token(edition)}"
+    end
+
+    path
+  end
+
+  def view_homepage_path
+    gov_uk_root_url
+  end
+
   def start_work_path(edition)
     send("start_work_edition_path", edition)
   end
@@ -49,6 +63,10 @@ def preview_url(_edition)
     Plek.external_url_for("draft-origin")
   end
 
+  def gov_uk_root_url
+    Plek.website_root
+  end
+
 private
 
   def should_have_auth_bypass_id?(edition)

app/views/homepage/popular_links/_sidebar.html.erb

@@ -5,9 +5,19 @@
     padding: true
   } %>
   <% if @latest_popular_links.state == "published" %>
-    <%= primary_button_for(@latest_popular_links, create_popular_links_path, "Create new edition") %>
+    <%= render "govuk_publishing_components/components/list", {
+      items: [
+        primary_button_for(@latest_popular_links, create_popular_links_path, "Create new edition"),
+        link_to("View on GOV.UK (opens in new tab)", view_homepage_path, class: "govuk-link")
+      ]
+    } %>
   <% else %>
-    <%= primary_link_button_for(edit_popular_links_path(@latest_popular_links), "Edit popular links") %>
-    <%= secondary_button_for(@latest_popular_links, publish_popular_links_path(@latest_popular_links), "Publish") %>
+    <%= render "govuk_publishing_components/components/list", {
+      items: [
+        primary_link_button_for(edit_popular_links_path(@latest_popular_links), "Edit popular links") ,
+        secondary_button_for(@latest_popular_links, publish_popular_links_path(@latest_popular_links), "Publish"),
+        link_to("Preview (opens in new tab)", preview_homepage_path(@latest_popular_links), class: "govuk-link")
+      ]
+    } %>
   <% end %>
-</div>
+</div>

test/integration/homepage_popular_links_test.rb

@@ -30,6 +30,10 @@ class HomepagePopularLinksTest < JavascriptIntegrationTest
       assert page.has_css?(".govuk-tag--green")
     end
 
+    should "have link to view 'GOV.UK'" do
+      assert page.has_link?("View on GOV.UK (opens in new tab)", href: Plek.website_root)
+    end
+
     should "have 'Create new edition' button" do
       assert page.has_text?("Create new edition")
     end
@@ -59,6 +63,12 @@ class HomepagePopularLinksTest < JavascriptIntegrationTest
       assert page.has_text?("Edit popular links")
     end
 
+    should "have link to preview on draft-origin" do
+      click_button("Create new edition")
+
+      assert page.has_link?("Preview (opens in new tab)", href: /#{Plek.external_url_for('draft-origin')}/)
+    end
+
     should "create a new record with next version and 'draft' status" do
       row = find_all(".govuk-summary-list__row")
       assert row[0].has_text?("Edition")

test/unit/helpers/admin/paths_helper_test.rb

@@ -39,6 +39,41 @@ class PathsHelperTest < ActionView::TestCase
     end
   end
 
+  context "#homepage popular links paths" do
+    setup do
+      Rails.stubs(:application).returns(
+        stub(
+          config: stub(jwt_auth_secret: JWT_AUTH_SECRET),
+        ),
+      )
+    end
+
+    context "when navigated to preview path" do
+      should "append a valid JWT token" do
+        popular_links = FactoryBot.build(:popular_links, auth_bypass_id: "123")
+        result = preview_homepage_path(popular_links)
+
+        path = result.gsub(/^(.*)\?.*$/, '\1')
+        assert_equal draft_origin.to_s, path
+
+        token = result.gsub(/.*token=(.*)$/, '\1')
+        payload = decoded_token_payload(token)
+
+        assert_equal payload["sub"], "123"
+        assert_equal payload["content_id"], "ad7968d0-0339-40b2-80bc-3ea1db8ef1b7"
+        assert_equal payload["iat"], Time.zone.now.to_i
+        assert_equal payload["exp"], 1.month.from_now.to_i
+      end
+    end
+
+    context "when navigated to homepage path" do
+      should "not append the JWT token" do
+        result = view_homepage_path
+        assert_no_match %r{&token=}, result
+      end
+    end
+  end
+
   def draft_origin
     Plek.find("draft-origin")
   end