diff --git a/README.md b/README.md
index d263aa3..b0224f1 100644
--- a/README.md
+++ b/README.md
@@ -123,7 +123,7 @@ After exposing the challenges (made accessible through HTTP or DNS) we can perfo
 be sure it works. For a DNS test call:
 
 ```php
-$client->selfTest($authorization, Client::TYPE_DNS);
+$client->selfTest($authorization, Client::VALIDATON_DNS);
 ``` 
 
 For a HTTP challenge test call: