diff --git a/selftest/selftest.py b/selftest/selftest.py
index 67a1d38..41027eb 100644
--- a/selftest/selftest.py
+++ b/selftest/selftest.py
@@ -201,6 +201,10 @@ def create_device(fhi, name, readings):
 
     os.system("cat fhem-config-addon.cfg >> {}".format(config["config_file"]))
 
+    if not os.path.exists(config["config_file"]):
+        log.error("Failed to create config file!")
+        sys.exit(-2)
+
 
     certs_dir = os.path.join(config["fhem_dir"], "certs")
     os.system("mkdir {}".format(certs_dir))