test/mm.py: Do not die if cromo or momdemmanager is not running

test/mm.py

 #!/usr/bin/python
 
 # Copyright (c) 2011 The Chromium OS Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import dbus
 import os
 
 MMPROVIDERS = [ 'org.chromium', 'org.freedesktop' ]
@@ skipping 80 matching lines @@
 
   Args:
     manager - the specific manager to use, if None check all known managers
 
   Returns:
     a list of (ModemManager object, modem dbus path)
   """
   if manager:
     managers = [manager]
   else:
-    managers = [ModemManager(x) for x in MMPROVIDERS]
+    managers = []
+    for provider in MMPROVIDERS:
+      try:
+        managers.append(ModemManager(provider))
+      except dbus.exceptions.DBusException, e:
+        if e._dbus_error_name != 'org.freedesktop.DBus.Error.ServiceUnknown':
+           raise
 
   result = []
   for m in managers:
     for path in m.manager.EnumerateDevices():
       result.append((m, path))
 
   return result
 
 
 def PickOneModem(modem_pattern, manager=None):
@@ skipping 16 matching lines @@
   """
   devices = EnumerateDevices(manager)
 
   matches = [(m, path) for m, path in devices if modem_pattern in path]
   if not matches:
     raise ValueError("No modems had substring: " + modem_pattern)
   if len(matches) > 1:
     raise ValueError("Expected only one modem, got: " +
                      ", ".join([path for _, path in matches]))
   return matches[0]