Update tests

app/views/datasets/_timeseries_data.html.erb

@@ -1,8 +1,6 @@
 <%
-  accordion_items = []
-
-  group_and_order(datafiles).each do |year, datafiles|
-    accordion_items << {
+  accordion_items = group_and_order(datafiles).map do |year, datafiles|
+    {
       heading: {
         text: year.presence || t('.other_data_files')
       },
@@ -14,5 +12,6 @@
 %>
 
 <%= render "govuk_publishing_components/components/accordion", {
+  id: "dgu-datafiles-year",
   items: accordion_items
-} %>
+} %>

spec/features/dataset_show_page_spec.rb

@@ -357,15 +357,17 @@
 
     scenario "are grouped by year when they contain timeseries datafiles" do
       index_and_visit(dataset)
-      expect(page).to have_css(".dgu-datafiles__year", count: 2)
-
-      correct_order = [
-        Time.zone.parse(datafile2["start_date"]).year.to_s,
-        Time.zone.parse(datafile1["start_date"]).year.to_s,
-      ]
-
-      actual_order = all("button.dgu-datafiles__year").map(&:text)
-      expect(actual_order).to eq correct_order
+      expect(page).to have_css("#dgu-datafiles-year")
+
+      within("#dgu-datafiles-year") do
+        correct_order = [
+          Time.zone.parse(datafile2["start_date"]).year.to_s,
+          Time.zone.parse(datafile1["start_date"]).year.to_s,
+        ]
+
+        actual_order = all(".govuk-accordion__section-button").map(&:text)
+        expect(actual_order).to eq correct_order
+      end
     end
 
     scenario "are not grouped when they contain non timeseries datafiles" do