diff --git a/OpenSSL/test/test_rand.py b/OpenSSL/test/test_rand.py
index 21910d7..c8645a5 100644
--- a/OpenSSL/test/test_rand.py
+++ b/OpenSSL/test/test_rand.py
@@ -22,6 +22,7 @@
         self.assertRaises(TypeError, rand.bytes, None)
         self.assertRaises(TypeError, rand.bytes, 3, None)
 
+    # XXX Test failure of the malloc() in rand_bytes.
 
     def test_bytes(self):
         """