Use input_api.os_path.pathsep instead of ';' to join a list of paths....

presubmit_canned_checks.py

 #!/usr/bin/env python
 # Copyright (c) 2006-2009 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """Generic presubmit checks that can be reused by other presubmit checks."""
 
 
 ### Description checks
 
@@ skipping 266 matching lines @@
     unit_test_name = unit_test
     # "python -m test.unit_test" doesn't work. We need to change to the right
     # directory instead.
     if '.' in unit_test:
       # Tests imported in submodules (subdirectories) assume that the current
       # directory is in the PYTHONPATH. Manually fix that.
       unit_test = unit_test.replace('.', '/')
       cwd = input_api.os_path.dirname(unit_test)
       unit_test = input_api.os_path.basename(unit_test)
       env = input_api.environ.copy()
-      backpath = [';'.join(['..'] * (cwd.count('/') + 1))]
+      backpath = [input_api.os_path.pathsep.join(['..'] * (cwd.count('/') + 1))]
       if env.get('PYTHONPATH'):
         backpath.append(env.get('PYTHONPATH'))
-      env['PYTHONPATH'] = ';'.join((backpath))
+      env['PYTHONPATH'] = input_api.os_path.pathsep.join((backpath))
     subproc = input_api.subprocess.Popen(
         [
           input_api.python_executable,
           "-m",
           "%s" % unit_test
         ],
         cwd=cwd,
         env=env,
         stdin=input_api.subprocess.PIPE,
         stdout=input_api.subprocess.PIPE,
         stderr=input_api.subprocess.PIPE)
     stdoutdata, stderrdata = subproc.communicate()
     # Discard the output if returncode == 0
     if subproc.returncode:
       outputs.append("Test '%s' failed with code %d\n%s\n%s\n" % (
           unit_test_name, subproc.returncode, stdoutdata, stderrdata))
   if outputs:
     return [message_type("%d unit tests failed." % len(outputs),
                                 long_text='\n'.join(outputs))]
   return []