diff --git a/tests/unit-tests/config-files/config-ca-4 b/tests/unit-tests/config-files/config-ca-4
new file mode 100644
index 0000000..98d6c92
--- /dev/null
+++ b/tests/unit-tests/config-files/config-ca-4
@@ -0,0 +1,14 @@
+{
+  "ca-prefix": "/ndn",
+  "ca-info": "unsupported challenge",
+  "max-validity-period": "86400",
+  "max-suffix-length": 3,
+  "probe-parameters":
+  [
+      { "probe-parameter-key": "full name" }
+  ],
+  "supported-challenges":
+  [
+      { "challenge": "something" }
+  ]
+}
\ No newline at end of file