diff --git a/testdata/request-sender.php b/testdata/request-sender.php
index 3b81594f..427e24d2 100644
--- a/testdata/request-sender.php
+++ b/testdata/request-sender.php
@@ -5,4 +5,8 @@ $workerName = $_GET["workerName"] ?? '';
 
 frankenphp_send_request($message, $workerName);
 
+// sleep to make sure request was received
+// TODO: solve this test-restart race condition with Futures instead?
+usleep(10_000);
+
 echo "request sent";