diff --git a/tests/bootstrap.php b/tests/bootstrap.php
index ace9a33c..9a087075 100644
--- a/tests/bootstrap.php
+++ b/tests/bootstrap.php
@@ -7,6 +7,7 @@
   require_once(__DIR__ . '/../Item.php');
   require_once(__DIR__ . '/../ItemList.php');
   require_once(__DIR__ . '/../PackedBox.php');
+  require_once(__DIR__ . '/../PackedBoxList.php');
   require_once(__DIR__ . '/../Packer.php');
 
  class TestBox implements Box {