Only preload misses on multifetch cache

1 files changed, 35 insertions, 0 deletions

diff --git a/actionview/test/activerecord/multifetch_cache_test.rb b/actionview/test/activerecord/multifetch_cache_test.rb
new file mode 100644
index 0000000000..12be069e69
--- /dev/null
+++ b/actionview/test/activerecord/multifetch_cache_test.rb
@@ -0,0 +1,35 @@
+# frozen_string_literal: true
+
+require "active_record_unit"
+require "active_record/railties/collection_cache_association_loading"
+
+ActionView::PartialRenderer.prepend(ActiveRecord::Railties::CollectionCacheAssociationLoading)
+
+class MultifetchCacheTest < ActiveRecordTestCase
+  fixtures :topics, :replies
+
+  def setup
+    view_paths = ActionController::Base.view_paths
+
+    @view = Class.new(ActionView::Base) do
+      def view_cache_dependencies
+        []
+      end
+
+      def combined_fragment_cache_key(key)
+        [ :views, key ]
+      end
+    end.new(view_paths, {})
+  end
+
+  def test_only_preloading_for_records_that_miss_the_cache
+    @view.render partial: "test/partial", collection: [topics(:rails)], cached: true
+
+    @topics = Topic.preload(:replies)
+
+    @view.render partial: "test/partial", collection: @topics, cached: true
+
+    assert_not @topics.detect { |topic| topic.id == topics(:rails).id }.replies.loaded?
+    assert     @topics.detect { |topic| topic.id != topics(:rails).id }.replies.loaded?
+  end
+end