'If the child process exits with a non-zero exit status, ``run_process``
raises ``CalledProcessError`` initialized with the command, exit
status, and any output.'

def test_on_error(self):

    command = self._failing_shell('echo    goodbye')
    exception = self._run_fail(command)
    expected = (1, command, 'goodbye\n')
    actual = (exception.returncode, exception.cmd, exception.output)
    self.assertEqual(expected, actual)
