Merge pull request #20884

Add #cache_key to ActiveRecord::Relation.

1 files changed, 70 insertions, 0 deletions

diff --git a/activerecord/test/cases/collection_cache_key_test.rb b/activerecord/test/cases/collection_cache_key_test.rb
new file mode 100644
index 0000000000..a794347889
--- /dev/null
+++ b/activerecord/test/cases/collection_cache_key_test.rb
@@ -0,0 +1,70 @@
+require "cases/helper"
+require "models/computer"
+require "models/developer"
+require "models/project"
+require "models/topic"
+require "models/post"
+require "models/comment"
+
+module ActiveRecord
+  class CollectionCacheKeyTest < ActiveRecord::TestCase
+    fixtures :developers, :projects, :developers_projects, :topics, :comments, :posts
+
+    test "collection_cache_key on model" do
+      assert_match(/\Adevelopers\/query-(\h+)-(\d+)-(\d+)\Z/, Developer.collection_cache_key)
+    end
+
+    test "cache_key for relation" do
+      developers = Developer.where(name: "David")
+      last_developer_timestamp = developers.order(updated_at: :desc).first.updated_at
+
+      assert_match /\Adevelopers\/query-(\h+)-(\d+)-(\d+)\Z/, developers.cache_key
+
+      /\Adevelopers\/query-(\h+)-(\d+)-(\d+)\Z/ =~ developers.cache_key
+
+      assert_equal Digest::MD5.hexdigest(developers.to_sql), $1
+      assert_equal developers.count.to_s, $2
+      assert_equal last_developer_timestamp.to_s(ActiveRecord::Base.cache_timestamp_format), $3
+    end
+
+    test "it triggers at most one query" do
+      developers =  Developer.where(name: "David")
+
+      assert_queries(1) { developers.cache_key }
+      assert_queries(0) { developers.cache_key }
+    end
+
+    test "it doesn't trigger any query if the relation is already loaded" do
+      developers =  Developer.where(name: "David").load
+      assert_queries(0) { developers.cache_key }
+    end
+
+    test "relation cache_key changes when the sql query changes" do
+      developers = Developer.where(name: "David")
+      other_relation =  Developer.where(name: "David").where("1 = 1")
+
+      assert_not_equal developers.cache_key, other_relation.cache_key
+    end
+
+    test "cache_key for empty relation" do
+      developers = Developer.where(name: "Non Existent Developer")
+      assert_match(/\Adevelopers\/query-(\h+)-0\Z/, developers.cache_key)
+    end
+
+    test "cache_key with custom timestamp column" do
+      topics = Topic.where("title like ?", "%Topic%")
+      last_topic_timestamp = topics(:fifth).written_on.utc.to_s(:nsec)
+      assert_match(last_topic_timestamp, topics.cache_key(:written_on))
+    end
+
+    test "cache_key with unknown timestamp column" do
+      topics = Topic.where("title like ?", "%Topic%")
+      assert_raises(ActiveRecord::StatementInvalid) { topics.cache_key(:published_at) }
+    end
+
+    test "collection proxy provides a cache_key" do
+      developers = projects(:active_record).developers
+      assert_match(/\Adevelopers\/query-(\h+)-(\d+)-(\d+)\Z/, developers.cache_key)
+    end
+  end
+end