1 files changed, 1 insertions, 1 deletions
diff --git a/testing/main.ts b/testing/main.ts
index 64d7e597e..838266f4b 100644
--- a/testing/main.ts
+++ b/testing/main.ts
@@ -1,7 +1,7 @@
 // Copyright 2018-2019 the Deno authors. All rights reserved. MIT license.
 import { runTests } from "./mod.ts";
 
-async function main() {
+async function main(): Promise<void> {
   // Testing entire test suite serially
   await runTests();
 }