1 files changed, 20 insertions, 1 deletions
diff --git a/activerecord/test/cases/collection_cache_key_test.rb b/activerecord/test/cases/collection_cache_key_test.rb
index 724234d7f4..a2874438c1 100644
--- a/activerecord/test/cases/collection_cache_key_test.rb
+++ b/activerecord/test/cases/collection_cache_key_test.rb
@@ -53,7 +53,7 @@ module ActiveRecord
 
     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)
+      last_topic_timestamp = topics(:fifth).written_on.utc.to_s(:usec)
       assert_match(last_topic_timestamp, topics.cache_key(:written_on))
     end
 
@@ -66,5 +66,24 @@ module ActiveRecord
       developers = projects(:active_record).developers
       assert_match(/\Adevelopers\/query-(\h+)-(\d+)-(\d+)\Z/, developers.cache_key)
     end
+
+    test "cache_key for loaded collection with zero size" do
+      Comment.delete_all
+      posts = Post.includes(:comments)
+      empty_loaded_collection = posts.first.comments
+
+      assert_match(/\Acomments\/query-(\h+)-0\Z/, empty_loaded_collection.cache_key)
+    end
+
+    test "cache_key for queries with offset which return 0 rows" do
+      developers = Developer.offset(20)
+      assert_match(/\Adevelopers\/query-(\h+)-0\Z/, developers.cache_key)
+    end
+
+    test "cache_key with a relation having selected columns" do
+      developers = Developer.select(:salary)
+
+      assert_match(/\Adevelopers\/query-(\h+)-(\d+)-(\d+)\Z/, developers.cache_key)
+    end
   end
 end