This test seems broken to me. It only check that `node.update_ips()`
is _not_ calling `provider.get_ips()`, which is *wrong*, as we need to
call it each time.

        # check with already present ips
        ip_unused = "127.0.0.3"
        provider.get_ips.return_value = (ip_unused, ip_unused)

        node.update_ips()

        self.assertEqual(node.ip_private, ip_private)
        self.assertEqual(node.ip_public, ip_public)