diff --git a/modules/monitoring/library/Monitoring/Backend/MonitoringBackend.php b/modules/monitoring/library/Monitoring/Backend/MonitoringBackend.php
index e18bd39a4..77f12dd8d 100644
--- a/modules/monitoring/library/Monitoring/Backend/MonitoringBackend.php
+++ b/modules/monitoring/library/Monitoring/Backend/MonitoringBackend.php
@@ -89,6 +89,14 @@ class MonitoringBackend implements Selectable, Queryable, ConnectionInterface
         return self::$instances[$name];
     }
 
+    /**
+     * Clear all cached instances. Mostly for testing purposes.
+     */
+    public static function clearInstances()
+    {
+        self::$instances = array();
+    }
+
     /**
      * Whether this backend is of a specific type
      *