diff --git a/tests/unit-tests/ca.conf.test b/tests/unit-tests/ca.conf.test
index f742a2b..bf795fd 100644
--- a/tests/unit-tests/ca.conf.test
+++ b/tests/unit-tests/ca.conf.test
@@ -9,5 +9,6 @@
   "supported-challenges":
   [
       { "challenge": "PIN" }
-  ]
+  ],
+  "max-suffix-length": 3
 }
\ No newline at end of file