Merge multi_fetch_fragments.

Makes caching a collection of template partials faster using `read_multi`
on the Rails cache store.

Some caching implementations have optimized `read_multi` so we don't have
to check in the cache store for every template.

1 files changed, 14 insertions, 0 deletions

diff --git a/actionview/test/template/render_test.rb b/actionview/test/template/render_test.rb
index f77b81f0ee..73871cf974 100644
--- a/actionview/test/template/render_test.rb
+++ b/actionview/test/template/render_test.rb
@@ -597,3 +597,17 @@ class LazyViewRenderTest < ActiveSupport::TestCase
     silence_warnings { Encoding.default_external = old }
   end
 end
+
+class CachedCollectionViewRenderTest < CachedViewRenderTest
+  test "with custom key" do
+    customer = Customer.new("david")
+    key = ActionController::Base.new.fragment_cache_key([customer, 'key'])
+
+    ActionView::PartialRenderer.collection_cache.write(key, 'Hello')
+
+    assert_equal "Hello",
+      @view.render(partial: "test/customer", collection: [customer], cache: ->(item) { [item, 'key'] })
+
+    ActionView::PartialRenderer.collection_cache.clear
+  end
+end