diff --git a/lib/devise_kerberos_authenticatable/kerberos_adapter.rb b/lib/devise_kerberos_authenticatable/kerberos_adapter.rb
index 9d6814c..6b6c536 100644
--- a/lib/devise_kerberos_authenticatable/kerberos_adapter.rb
+++ b/lib/devise_kerberos_authenticatable/kerberos_adapter.rb
@@ -5,7 +5,7 @@ module Devise
   module KerberosAdapter
     def self.valid_credentials?(username, password)
       if Rails.env.test? && username == 'test' && password == 'test' then
-        true
+        return true
       end
 
       krb5 = Krb5.new