Throw and a small fix to If.

tools/testing/test_case.py

 # Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 # for details. All rights reserved. Use of this source code is governed by a
 # BSD-style license that can be found in the LICENSE file.
 
 """Common TestCase subclasses used to define a single test."""
 
 import os
 import tempfile
 
 import test
@@ skipping 68 matching lines @@
     """Determine if this is a negative test. by looking at @ directives.
 
     A negative test is considered to pas if its outcome is FAIL.
 
     Returns:
       True if this is a negative test.
     """
     if self.kind == 'compile-time error':
       return True
     if self.kind == 'runtime error':
-      return False
+      return True
     if self.kind == 'static type error':
       return self.run_arch.HasFatalTypeErrors()
     return False
 
 
 class BrowserTestCase(StandardTestCase):
   """A test case that executes inside a browser (or DumpRenderTree)."""
 
   def __init__(self, context, path, filename,
                fatal_static_type_errors, mode, arch, component, vm_options=None):
@@ skipping 61 matching lines @@
             self.filename]
 
     return cmd
 
   def GetName(self):
     return self.path[-1]
 
   def Cleanup(self):
     if not self.context.keep_temporary_files:
       self.run_arch.Cleanup()