diff --git a/tools/tests/bundle-ignore-files.js b/tools/tests/bundle-ignore-files.js
index cda85d78c2..500c1c823c 100644
--- a/tools/tests/bundle-ignore-files.js
+++ b/tools/tests/bundle-ignore-files.js
@@ -1,3 +1,4 @@
+var _ = require('underscore');
 var selftest = require('../tool-testing/selftest.js');
 var Sandbox = selftest.Sandbox;
 var files = require('../fs/files.js');