diff --git a/tests/Doctrine/Tests/OrmFunctionalTestCase.php b/tests/Doctrine/Tests/OrmFunctionalTestCase.php
index ba54da95c..5515e904b 100644
--- a/tests/Doctrine/Tests/OrmFunctionalTestCase.php
+++ b/tests/Doctrine/Tests/OrmFunctionalTestCase.php
@@ -294,7 +294,11 @@ abstract class OrmFunctionalTestCase extends OrmTestCase
         // the actual database platform used during execution has effect on some
         // metadata mapping behaviors (like the choice of the ID generation).
         if (is_null(self::$_metadataCacheImpl)) {
-            self::$_metadataCacheImpl = new \Doctrine\Common\Cache\ArrayCache;
+            if (isset($GLOBALS['DOCTRINE_CACHE_IMPL'])) {
+                self::$_metadataCacheImpl = new $GLOBALS['DOCTRINE_CACHE_IMPL'];
+            } else {
+                self::$_metadataCacheImpl = new \Doctrine\Common\Cache\ArrayCache;
+            }
         }
 
         if (is_null(self::$_queryCacheImpl)) {