'Mountpoints are children of the mount root.'

def test_mount_root(self):

    mount_root = FilePath(self.mktemp())
    mount_root.makedirs()
    pool = StoragePool(reactor, create_zfs_pool(self), mount_root)
    service = service_for_pool(self, pool)
    volume = service.get(MY_VOLUME)
    d = pool.create(volume)
    def gotFilesystem(filesystem):
        self.assertEqual(filesystem.get_path(), mount_root.child(volume_to_dataset(volume)))
    d.addCallback(gotFilesystem)
    return d
