Preload only uncached messages and reduce rendering overhead (#292)

* Preload only uncached messages and reduce rendering overhead

* Keep benchmark summaries without raw JSON results

* Use Ruby benchmark drivers and keep generated results out of the repo

test/controllers/messages_caching_test.rb

@@ -0,0 +1,48 @@
+require "test_helper"
+require "active_record/testing/query_assertions"
+
+class MessagesCachingTest < ActionDispatch::IntegrationTest
+  include ActiveRecord::Assertions::QueryAssertions
+
+  setup do
+    sign_in :david
+  end
+
+  test "cached pages skip presentation queries and refresh edited messages" do
+    with_memory_cache do
+      get room_messages_url(rooms(:watercooler))
+      assert_response :success
+      original = response.body
+
+      assert_no_queries_match(/action_text_rich_texts|active_storage_attachments|boosts/) do
+        get room_messages_url(rooms(:watercooler))
+      end
+      assert_response :success
+      assert_equal original, response.body
+
+      messages(:fourth).update! body: "Updated cached message"
+      get room_messages_url(rooms(:watercooler))
+      assert_response :success
+      assert_select "#" + dom_id(messages(:fourth)), text: /Updated cached message/
+    end
+  end
+
+  private
+    def with_memory_cache
+      old_cache = Rails.cache
+      old_collection_cache = ActionView::PartialRenderer.collection_cache
+      old_controller_cache = MessagesController.cache_store
+      old_caching = MessagesController.perform_caching
+
+      Rails.cache = ActiveSupport::Cache::MemoryStore.new
+      ActionView::PartialRenderer.collection_cache = Rails.cache
+      MessagesController.cache_store = Rails.cache
+      MessagesController.perform_caching = true
+      yield
+    ensure
+      Rails.cache = old_cache
+      ActionView::PartialRenderer.collection_cache = old_collection_cache
+      MessagesController.cache_store = old_controller_cache
+      MessagesController.perform_caching = old_caching
+    end
+end