diff --git a/tests/Feature/WatchdogLockContentionTest.php b/tests/Feature/WatchdogLockContentionTest.php
index bc09fdd..7e23f3f 100644
--- a/tests/Feature/WatchdogLockContentionTest.php
+++ b/tests/Feature/WatchdogLockContentionTest.php
@@ -50,7 +50,7 @@ function dockerStub(string $running = "app\nredis"): string
         sleep "\${STUB_SLEEP:-1}"
         case "\$*" in
             *config*)                   printf '%s\\n' app redis ;;
-            *"ps "*)                    printf '%s\\n' $running ;;
+            *"ps "*)                    printf '%s\\n' '$running' ;;
             *getent*)                   exit "\${STUB_REDIS_RC:-0}" ;;
             *storage/framework/down*)   exit 1 ;;
             *" up "*)                   touch "\$STUB_UP_CALLED" ;;