diff --git a/server/helpers/core-utils.ts b/server/helpers/core-utils.ts
index 5cb21b9..ad653e4 100644
--- a/server/helpers/core-utils.ts
+++ b/server/helpers/core-utils.ts
@@ -3,7 +3,7 @@ function isTestInstance () {
 }
 
 function waitMs (ms: number) {
-  return new Promise(res => {
+  return new Promise<void>(res => {
     setTimeout(() => res(), ms)
   })
 }