[foozzie] Pass startup test

tools/foozzie/v8_foozzie.py

 #!/usr/bin/env python
 # Copyright 2016 the V8 project authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """
 V8 correctness fuzzer launcher script.
 """
 
 import argparse
@@ skipping 83 matching lines @@
       '--first-config', help='first configuration', default='fullcode')
   parser.add_argument(
       '--second-config', help='second configuration', default='fullcode')
   parser.add_argument(
       '--first-d8', default='d8',
       help='optional path to first d8 executable, '
            'default: bundled in the same directory as this script')
   parser.add_argument(
       '--second-d8',
       help='optional path to second d8 executable, default: same as first')
-  parser.add_argument('testcase', help='path to test case')
+  parser.add_argument('testcase', help='path to test case', nargs='?')
   options = parser.parse_args()
 
+  if not options.testcase:
+    # Don't check further as we want to bail out early without test case.
+    return options
+
   # Ensure we make a sane comparison.
   assert (options.first_arch != options.second_arch or
           options.first_config != options.second_config) , (
       'Need either arch or config difference.')
   assert options.first_arch in SUPPORTED_ARCHS
   assert options.second_arch in SUPPORTED_ARCHS
   assert options.first_config in CONFIGS
   assert options.second_config in CONFIGS
 
   # Ensure we have a test case.
@@ skipping 61 matching lines @@
   if bug:
     print FAILURE_HEADER_TEMPLATE % dict(
         configs='', sources='', suppression=bug)
     return True
   return False
 
 
 def main():
   options = parse_args()
 
+  if not options.testcase:
+    print '# V8 correctness - pass - no test file given'
+    return RETURN_PASS
+
   # Suppressions are architecture and configuration specific.
   suppress = v8_suppressions.get_suppression(
       options.first_arch, options.first_config,
       options.second_arch, options.second_config,
   )
 
   if test_pattern_bailout(options.testcase, suppress.ignore):
     return RETURN_FAIL
 
   # Get metadata.
@@ skipping 71 matching lines @@
         configs='', sources='', suppression='wrong_usage')
     result = RETURN_FAIL
   except Exception as e:
     print FAILURE_HEADER_TEMPLATE % dict(
         configs='', sources='', suppression='internal_error')
     print '# Internal error: %s' % e
     traceback.print_exc(file=sys.stdout)
     result = RETURN_FAIL
 
   sys.exit(result)