diff --git a/test/closing.test.js b/test/closing.test.js
index 1eaa23c..d4ccd5a 100644
--- a/test/closing.test.js
+++ b/test/closing.test.js
@@ -1,3 +1,5 @@
+'use strict'
+
 const test = require('tap').test
 const Fastify = require('fastify')
 const fastifyMysql = require('../index')