diff --git a/tests/threads/run_test_future.ml b/tests/threads/run_test_future.ml
index 9c94b7fc..bea590fe 100644
--- a/tests/threads/run_test_future.ml
+++ b/tests/threads/run_test_future.ml
@@ -2,6 +2,7 @@
 (** Test Future *)
 
 open OUnit
+open CCFun
 
 module Future = CCFuture
 open Future.Infix