test_search_files failing in Nightlies PPA test runs

This error is occurring in the ubuntuone-client nightlies builds, on all architectures:

[FAIL]
Traceback (most recent call last):
  File "/usr/lib/python2.7/dist-packages/twisted/internet/defer.py", line 1045, in _inlineCallbacks
    result = g.send(result)
  File "/build/buildd/ubuntuone-client-4.1+r1352/tests/platform/test_tools.py", line 223, in test_search_files
    self.assertEqual(result, expected)
  File "/usr/lib/python2.7/dist-packages/twisted/trial/unittest.py", line 271, in assertEqual
    % (msg, pformat(first), pformat(second)))
twisted.trial.unittest.FailTest: not equal:
a = dbus.Array([], signature=dbus.Signature('s'))
b = ['/build/buildd/ubuntuone-client-4.1+r1352/_trial_temp/trial/_trial_temp/tests.platform.test_tools/TestToolsBasic/test_search_files/root_dir/path/to/file_test',
 '/build/buildd/ubuntuone-client-4.1+r1352/_trial_temp/trial/_trial_temp/tests.platform.test_tools/TestToolsBasic/test_search_files/root_dir/path/to/my_files']

tests.platform.test_tools.TestToolsBasic.test_search_files