diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 24d3e00..4ea7ea3 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -45,6 +45,7 @@ Thank you! We'll try to respond as quickly as possible.
 6. Create a new pull request
 
 Please try to keep your pull request focused in scope and avoid including unrelated commits.
+Please run tests against redis cluster locally with `--redis_cluster` flag to ensure that code works for Redis cluster. TODO: Run tests using Redis cluster on CI.
 
 After you have submitted your pull request, we'll try to get back to you as soon as possible. We may suggest some changes or improvements.