Make mojob.py test succeed on Windows.

mojo/tools/mojob.py

 #!/usr/bin/env python
 # Copyright 2014 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.
 
 # This a simple script to make building/testing Mojo components easier.
 
 import argparse
 import os
 import platform
@@ skipping 86 matching lines @@
 
     return subprocess.call(['ninja', '-j', '1000', '-l', '100', '-C', out_dir,
                             'root'])
   else:
     return subprocess.call(['ninja', '-C', out_dir, 'root'])
 
 
 def run_unittests(args):
   out_dir = get_out_dir(args)
   print 'Running unit tests in %s ...' % out_dir
-  command = []
+  command = ['python']
   if platform.system() == 'Linux':
     command.append('./testing/xvfb.py')
     command.append(out_dir)
 
   command.append(os.path.join('mojo', 'tools', 'test_runner.py'))
   command.append(os.path.join('mojo', 'tools', 'data', 'unittests'))
   command.append(out_dir)
   command.append('mojob_test_successes')
   return subprocess.call(command)
 
 
 def run_skytests(args):
   out_dir = get_out_dir(args)
   if platform.system() != 'Linux':
     return 0
 
   command = []
   command.append('./testing/xvfb.py')
   command.append(out_dir)
   command.append('sky/tools/test_sky')
   command.append('-t')
   command.append('Debug' if args.debug else 'Release')
   command.append('--no-new-test-results')
   command.append('--no-show-results')
   command.append('--verbose')
   return subprocess.call(command)
 
 
 def run_pytests(args):
+  if platform.system() == 'Windows':
+    print ('pytests aren\'t supported on Windows because the Python bindings '
+           'aren\'t build there.')
+    return
   out_dir = get_out_dir(args)
   print 'Running python tests in %s ...' % out_dir
-  command = []
+  command = ['python']
   command.append(os.path.join('mojo', 'tools', 'run_mojo_python_tests.py'))
   exit_code = subprocess.call(command)
   if exit_code:
     return exit_code
 
-  command = []
+  command = ['python']
   command.append(os.path.join('mojo', 'tools',
                               'run_mojo_python_bindings_tests.py'))
   command.append('--build-dir=' + out_dir)
   return subprocess.call(command)
 
 
 def test(args):
   exit_code = run_unittests(args)
   if exit_code:
     return exit_code
@@ skipping 98 matching lines @@
     args.clang = False
 
   if platform.system() == 'Windows':
     args.clang = False
 
   return args.func(args)
 
 
 if __name__ == '__main__':
   sys.exit(main())