'Use ``run_process`` to run a child shell process which is expected to
exit with an error code.
:param list command: An argument list to use to launch the child
process.
:raise: A test-failing exception if ``run_process`` does not raise
``CalledProcessError``.
:return: The ``CalledProcessError`` raised by ``run_process``.'

def _run_fail(self, command):

    exception = self.assertRaises(CalledProcessError, run_process, command)
    return exception
