Add detection of contextual title translation

app/helpers/application_helper.rb

@@ -3,6 +3,18 @@ def page_text_direction
     I18n.t("i18n.direction", locale: I18n.locale, default: "ltr")
   end
 
+  def t_locale_fallback(key, options = {})
+    options['locale'] = I18n.locale
+    options[:fallback] = nil
+    translation = I18n.t(key, options)
+
+    if translation.nil? || translation.include?("translation missing")
+      I18n.default_locale
+    else
+      return nil
+    end
+  end
+
   def wrapper_class
     "direction-#{page_text_direction}" if page_text_direction
   end

app/presenters/content_item/title_and_context.rb

@@ -4,6 +4,7 @@ def title_and_context
       {
         title: title,
         context: I18n.t("content_item.schema_name.#{document_type}", count: 1),
+        context_locale: t_locale_fallback("content_item.schema_name.#{document_type}", count: 1),
         average_title_length: "long"
       }
     end

app/presenters/content_item_presenter.rb

@@ -1,5 +1,6 @@
 class ContentItemPresenter
   include ContentItem::Withdrawable
+  include ApplicationHelper
 
   attr_reader :content_item,
               :requested_content_item_path,

app/views/content_items/publication.html.erb

@@ -8,6 +8,7 @@
   <div class="govuk-grid-column-two-thirds">
     <%= render 'govuk_publishing_components/components/title',
        context: t("content_item.schema_name.#{@content_item.document_type}", count: 1),
+       context_locale: t_locale_fallback("content_item.schema_name.#{@content_item.document_type}", count: 1),
        title: @content_item.title,
        average_title_length: "long" %>
   </div>

test/helpers/application_helper_test.rb

@@ -12,4 +12,23 @@ class ApplicationHelperTest < ActionView::TestCase
     self.stubs(:request).returns(ActionDispatch::TestRequest.create("PATH_INFO" => '/foo/bar', "QUERY_STRING" => 'ham=jam&spam=gram'))
     assert_equal '/foo/bar', current_path_without_query_string
   end
+
+  test "#t_locale_fallback returns nil for a string with a locale translation" do
+    fallback = t_locale_fallback("content_item.schema_name.imported", count: 1, locale: :de)
+    assert_equal nil, fallback
+  end
+
+  test "#t_locale_fallback returns default locale for a string with no locale translation" do
+    I18n.with_locale(:de) do
+      fallback = t_locale_fallback("content_item.schema_name.decision", count: 1, locale: :de)
+      assert_equal :en, fallback
+    end
+  end
+
+  test "#t_locale_fallback returns fallback for irrelevant key" do
+    I18n.with_locale(:de) do
+      fallback = t_locale_fallback("blah", count: 1)
+      assert_equal :en, fallback
+    end
+  end
 end

test/presenters/corporate_information_page_presenter_test.rb

@@ -30,7 +30,7 @@ def schema_name
 
     test 'has title without context' do
       assert presented_item.is_a?(ContentItem::TitleAndContext)
-      title_component_params = { title: "About us" }
+      title_component_params = { title: "About us", context_locale: :en }
 
       assert_equal title_component_params, presented_item.title_and_context
     end

test/presenters/specialist_document_presenter_test.rb

@@ -83,7 +83,9 @@ class PresentedSpecialistDocument < SpecialistDocumentTestCase
       assert presented_item('aaib-reports').is_a?(ContentItem::TitleAndContext)
       title_component_params = {
                                   title: schema_item('aaib-reports')['title'],
-                                  average_title_length: 'long'
+                                  context_locale: nil,
+                                  average_title_length: 'long',
+
                                }
 
       assert_equal title_component_params, presented_item('aaib-reports').title_and_context