Show backtraces when test fail

index.php

@@ -40,7 +40,7 @@ require_once file_exists(PIWIK_INCLUDE_PATH . '/vendor/autoload.php')
     : PIWIK_INCLUDE_PATH . '/../../autoload.php'; // Piwik is installed as a dependency
 
 if(!defined('PIWIK_PRINT_ERROR_BACKTRACE')) {
-    define('PIWIK_PRINT_ERROR_BACKTRACE', true);
+    define('PIWIK_PRINT_ERROR_BACKTRACE', false);
 }
 
 require_once PIWIK_INCLUDE_PATH . '/core/dispatch.php';
\ No newline at end of file

tests/PHPUnit/bootstrap.php

 <?php
 define('PIWIK_TEST_MODE', true);
-define('PIWIK_PRINT_ERROR_BACKTRACE', false);
+define('PIWIK_PRINT_ERROR_BACKTRACE', true);
 
 if (!defined("PIWIK_PATH_TEST_TO_ROOT")) {
     define('PIWIK_PATH_TEST_TO_ROOT', realpath(dirname(__FILE__) . '/../..'));