Show either investments header or results summary

We were showing the header when there were no search terms but there
were advanced search filters, unlike what we do for debates and
proposals. Besides, we were already hiding the header when there were
search terms, so it makes sense to hide it when using the advanced
search too.

We're using the `@search_terms` and `@advanced_search_terms` instance
variables in order to be consistent with what we do in the debates and
proposals sections.

app/views/budgets/investments/index.html.erb

@@ -16,17 +16,14 @@
 <% end %>
 
 <main id="budget-investments-main">
-
+  <% if @search_terms || @advanced_search_terms %>
-  <% unless params[:search].present? %>
-    <%= render "/budgets/investments/header" %>
-  <% end %>
-
-  <% if params[:search].present? || params[:advanced_search].present? %>
     <%= render Shared::SearchResultsSummaryComponent.new(
       results: @investments,
-      search_terms: params[:search],
+      search_terms: @search_terms,
-      advanced_search_terms: params[:advanced_search]
+      advanced_search_terms: @advanced_search_terms
     ) %>
+  <% else %>
+    <%= render "/budgets/investments/header" %>
   <% end %>
 
   <div class="row">

spec/system/budgets/investments_spec.rb

@@ -219,6 +219,23 @@ describe "Budget Investments" do
       expect(page).not_to have_content "Feasible health"
       expect(page).not_to have_content "Unfeasible health"
     end
+
+    scenario "Advanced search without search terms" do
+      create(:budget_heading, group: heading.group)
+      create(:budget_investment, heading: heading, title: "Old thing", created_at: 2.years.ago)
+      create(:budget_investment, heading: heading, title: "Newest thing", created_at: 1.hour.ago)
+
+      visit budget_investments_path(budget, heading: heading)
+
+      click_button "Advanced search"
+      select "Last year", from: "By date"
+      click_button "Filter"
+
+      expect(page).to have_content "There is 1 investment"
+      expect(page).to have_content "Newest thing"
+      expect(page).not_to have_content "Old thing"
+      within("main") { expect(page).not_to have_content "Participatory budgeting" }
+    end
   end
 
   context("Filters") do