diff --git a/.travis.yml b/.travis.yml
index a0aaf0cc3ce67ed434552f19e99e4f34720bebea..29adc1e452771f1575064e081518604a84c4563a 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -6,6 +6,10 @@ php:
 - 7.1
 - 7.2
 - 7.3
+- hhvm
+matrix:
+  allow_failures:
+  - php: hhvm
 before_script:
 - composer update
 - if [[ "$TRAVIS_PHP_VERSION" == "7.0" ]]; then composer require --dev vimeo/psalm:0.3.92; fi
diff --git a/modules/oauth/lib/OAuthServer.php b/modules/oauth/lib/OAuthServer.php
index b6607e6feb6bfeb4372dd1c50462295f6325821d..41e60383ad92a01ebecc95fb7695f5d6c14c59eb 100644
--- a/modules/oauth/lib/OAuthServer.php
+++ b/modules/oauth/lib/OAuthServer.php
@@ -11,7 +11,7 @@ require_once(dirname(dirname(__FILE__)).'/libextinc/OAuth.php');
  * @package SimpleSAMLphp
  */
 
-class OAuthServer extends OAuthServer
+class OAuthServer extends \OAuthServer
 {
     public function __construct($store)
     {