diff --git a/lib/test.js b/lib/test.js
index 2d68fd1b..4dc90aa2 100644
--- a/lib/test.js
+++ b/lib/test.js
@@ -237,13 +237,13 @@ Test.prototype._assert = function assert (ok, opts) {
             if (filem[1].slice(0, dir.length) === dir) {
                 continue;
             }
-            
-            res.functionName = s[0];
+
+            res.functionName = s.length > 1 ? s[0] : '<anonymous>';
             res.file = filem[1];
             res.line = Number(filem[2]);
             if (filem[3]) res.column = filem[3];
             
-            res.at = m[1];
+            res.at = s.length > 1 ? m[1] : '<anonymous> (' + m[1] + ')';
             break;
         }
     }