diff --git a/Tests/ErrorProcessInitiator.php b/Tests/ErrorProcessInitiator.php
index 54168022..0b75add6 100644
--- a/Tests/ErrorProcessInitiator.php
+++ b/Tests/ErrorProcessInitiator.php
@@ -25,7 +25,7 @@
     while (!str_contains($process->getOutput(), 'ready')) {
         usleep(1000);
     }
-    $process->signal(\SIGSTOP);
+    $process->isRunning() && $process->signal(\SIGSTOP);
     $process->wait();
 
     return $process->getExitCode();