cros_uprevchrome_unittest fails if the chroot doesn't exist with this error:


clean$cli/cros/cros_uprevchrome_unittest 
...16:10:02: ERROR: pfq_build 100 not valid, status: pass
.E.
======================================================================
ERROR: [chromite.cli.cros.cros_uprevchrome_unittest] CrosUprevChromeTest.testSuccessfulRun
Test a successful uprevchrome run.
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/usr/local/google/home/dgarrett/sand/clean/chromite/lib/timeout_util.py", line 191, in TimeoutWrapper
    return func(*args, **kwargs)
  File "/usr/local/google/home/dgarrett/sand/clean/chromite/cli/cros/cros_uprevchrome_unittest.py", line 111, in testSuccessfulRun
    self.cmd_mock.inst.Run()
  File "<string>", line 3, in Run
  File "/usr/local/google/home/dgarrett/sand/clean/chromite/third_party/mock.py", line 955, in __call__
    return _mock_self._mock_call(*args, **kwargs)
  File "/usr/local/google/home/dgarrett/sand/clean/chromite/third_party/mock.py", line 1018, in _mock_call
    ret_val = effect(*args, **kwargs)
  File "/usr/local/google/home/dgarrett/sand/clean/chromite/cli/cros/cros_uprevchrome_unittest.py", line 32, in Run
    command_unittest.MockCommand.Run(self, inst)
  File "/usr/local/google/home/dgarrett/sand/clean/chromite/cli/command_unittest.py", line 95, in Run
    return self.backup['Run'](inst)
  File "/usr/local/google/home/dgarrett/sand/clean/chromite/cli/cros/cros_uprevchrome.py", line 376, in Run
    work_dir = tempfile.mkdtemp(prefix='uprevchrome_', dir=tmp_override)
  File "/usr/lib/python2.7/tempfile.py", line 333, in mkdtemp
    _os.mkdir(file, 0700)
OSError: [Errno 2] No such file or directory: '/usr/local/google/home/dgarrett/sand/clean/chroot/tmp/uprevchrome_dNJBbb'

----------------------------------------------------------------------
Ran 6 tests in 0.035s

FAILED (errors=1)