diff -r d382dacfd73f -r ce08b0b23949 rt/vmtest/src/main/java/org/apidesign/bck2brwsr/vmtest/impl/Bck2BrwsrCase.java
--- a/rt/vmtest/src/main/java/org/apidesign/bck2brwsr/vmtest/impl/Bck2BrwsrCase.java	Tue Feb 26 16:54:16 2013 +0100
+++ b/rt/vmtest/src/main/java/org/apidesign/bck2brwsr/vmtest/impl/Bck2BrwsrCase.java	Sun Apr 07 16:11:56 2013 +0200
@@ -75,7 +75,7 @@
             String res = c.invoke();
             value = res;
             if (fail) {
-                int idx = res.indexOf(':');
+                int idx = res == null ? -1 : res.indexOf(':');
                 if (idx >= 0) {
                     Class<? extends Throwable> thrwbl = null;
                     try {