Merge pull request #3269 from alphagov/fix-hmrc-siblings

Do not attempt to show siblings if there aren't any

app/presenters/hmrc_manual_section_presenter.rb

@@ -30,23 +30,25 @@ def breadcrumbs
   end
 
   def previous_and_next_links
-    siblings = {}
+    return unless siblings
+
+    section_siblings = {}
 
     if previous_sibling
-      siblings[:previous_page] = {
+      section_siblings[:previous_page] = {
         title: I18n.t("manuals.previous_page"),
         url: previous_sibling["base_path"],
       }
     end
 
     if next_sibling
-      siblings[:next_page] = {
+      section_siblings[:next_page] = {
         title: I18n.t("manuals.next_page"),
         url: next_sibling["base_path"],
       }
     end
 
-    siblings
+    section_siblings
   end
 
 private
@@ -68,6 +70,8 @@ def siblings
 
     child_section_groups = parent_for_section.dig("details", "child_section_groups")
 
+    return unless child_section_groups
+
     sibling_child_sections = child_section_groups.map do |group|
       included_section = group["child_sections"].find { |section| section["section_id"].include?(current_section_id) }
       group["child_sections"] if included_section.present?

test/presenters/hmrc_manual_section_presenter_test.rb

@@ -146,6 +146,19 @@ class PresentedHmrcManualSectionTest < HmrcManualSectionPresenterTestCase
       assert_equal expected_previous_link, presented_manual_section.previous_and_next_links
     end
 
+    test "presents no previous or next links if there is no previous or next section" do
+      manual_base_path = schema_item("vatgpb2000")["details"]["manual"]["base_path"]
+      manual = schema_item("vat-government-public-bodies", "hmrc_manual")
+
+      manual["details"]["child_section_groups"] = []
+
+      stub_content_store_has_item(manual_base_path, manual.to_json)
+
+      expected_links = {}
+
+      assert_equal expected_links, presented_manual_section.previous_and_next_links
+    end
+
     def presented_manual_section(overrides = {})
       presented_item("vatgpb2000", overrides)
     end