diff --git a/tests/PHPUnit/IntegrationTestCase.php b/tests/PHPUnit/IntegrationTestCase.php
index 27affa6ef44fbc7c9f62faf68d99e8dca0e60250..dea18ed0510dcd1855db2a064b817e7a115c3a4d 100755
--- a/tests/PHPUnit/IntegrationTestCase.php
+++ b/tests/PHPUnit/IntegrationTestCase.php
@@ -97,6 +97,7 @@ abstract class IntegrationTestCase extends PHPUnit_Framework_TestCase
         Piwik_Common::deleteTrackerCache();
         Piwik_Config::getInstance()->clear();
         Piwik_TablePartitioning::$tablesAlreadyInstalled = null;
+        Piwik_PDFReports_API::$cache = array();
         Zend_Registry::_unsetInstance();
 
         $_GET = $_REQUEST = array();