add a spec

spec/system/disable_sort_spec.rb

@@ -0,0 +1,24 @@
+# frozen_string_literal: true
+
+describe "Disabling topic list sorting", type: :system do
+  fab!(:category)
+  let(:category_page) { PageObjects::Pages::Category.new }
+
+  before do
+    SiteSetting.calendar_enabled = true
+    Fabricate.times(2, :topic, category:)
+  end
+
+  it "disables the ability to sort topic list columns" do
+    category_page.visit(category)
+    expect(find("th.activity")).to match_selector(".sortable")
+
+    category.custom_fields["disable_topic_resorting"] = true
+    page.refresh
+    expect(find("th.activity")).to match_selector(".sortable")
+
+    SiteSetting.disable_resorting_on_categories_enabled = true
+    page.refresh
+    expect(find("th.activity")).to_not match_selector(".sortable")
+  end
+end