'``mount`` accepts mount options such as ``ro``.'

def test_mount_options(self):

    filename = random_name(self)
    filecontent = random_name(self)
    mount_directory = self.make_temporary_directory()
    with mount(self.device.device, mount_directory, options=['ro']) as mountpoint:
        e = self.assertRaises(OSError, mountpoint.child(filename).setContent, filecontent)
        self.assertEqual(errno.EROFS, e.errno)
