diff --git a/js/src/tests/lib/tests.py b/js/src/tests/lib/tests.py
index 50b1058d6aec..041eefde3b7f 100644
--- a/js/src/tests/lib/tests.py
+++ b/js/src/tests/lib/tests.py
@@ -249,3 +249,6 @@ class RefTestCase(object):
 
     def __hash__(self):
         return self.path.__hash__()
+
+    def __repr__(self):
+        return "<lib.tests.RefTestCase %s>" % (self.path,)