diff --git a/tests/phpunit/scheduler/AsyncPoolTest.php b/tests/phpunit/scheduler/AsyncPoolTest.php
index 294092ead..d7bacd391 100644
--- a/tests/phpunit/scheduler/AsyncPoolTest.php
+++ b/tests/phpunit/scheduler/AsyncPoolTest.php
@@ -33,7 +33,6 @@ use function define;
 use function dirname;
 use function microtime;
 use function sys_get_temp_dir;
-use function tempnam;
 use function usleep;
 
 class AsyncPoolTest extends TestCase{