diff --git a/test/inc-testcase.js b/test/inc-testcase.js
index 2c2245e..8e0aacd 100644
--- a/test/inc-testcase.js
+++ b/test/inc-testcase.js
@@ -383,12 +383,12 @@ function outputTestFailures( failures )
         cur = failures[ i ];
 
         name = cur[ 0 ];
-        e    = cur[ 1 ];
+        e    = cur[ 1 ];  // ideally Error, but may not be
 
         // output the name followed by the stack trace
         testPrint(
             '#' + i + ' ' + name + '\n'
-            + e.stack + "\n\n"
+            + ( e.stack || e ) + "\n\n"
         );
     }
 }