--- a/js/src/tests/jstests.py
+++ b/js/src/tests/jstests.py
@@ -144,16 +144,23 @@ class ResultsSink:
     def list(self):
         for label, paths in sorted(self.groups.items()):
             if label == '': continue
 
             print label
             for path in paths:
                 print '    %s'%path
 
+        if OPTIONS.failure_file:
+              failure_file = open(OPTIONS.failure_file, 'w')
+              if not self.all_passed():
+                  for path in self.groups['REGRESSIONS']:
+                      print >> failure_file, path
+              failure_file.close()
+
         suffix = '' if self.finished else ' (partial run -- interrupted by user)'
         if self.all_passed():
             print 'PASS' + suffix
         else:
             print 'FAIL' + suffix
 
     def all_passed(self):
         return 'REGRESSIONS' not in self.groups
@@ -213,16 +220,18 @@ if __name__ == '__main__':
     op.add_option('-g', '--debug', dest='debug', action='store_true',
                   help='run test in debugger')
     op.add_option('--valgrind', dest='valgrind', action='store_true',
                   help='run tests in valgrind')
     op.add_option('--valgrind-args', dest='valgrind_args',
                   help='extra args to pass to valgrind')
     op.add_option('-c', '--check-manifest', dest='check_manifest', action='store_true',
                   help='check for test files not listed in the manifest')
+    op.add_option('--failure-file', dest='failure_file',
+                  help='write tests that have not passed to the given file')
     (OPTIONS, args) = op.parse_args()
     if len(args) < 1:
         if not OPTIONS.check_manifest:
             op.error('missing JS_SHELL argument')
         JS, args = None, []
     else:
         JS, args = args[0], args[1:]
     # Convert to an absolute path so we can run JS from a different directory.