@Override
    public OpenstackVtapNetwork createVtapNetwork(Mode mode, Integer networkId, IpAddress serverIp) {
        checkNotNull(mode, VTAP_DESC_NULL, "mode");
        checkNotNull(serverIp, VTAP_DESC_NULL, "serverIp");
        DefaultOpenstackVtapNetwork vtapNetwork = DefaultOpenstackVtapNetwork.builder()
                .mode(mode)
                .networkId(networkId)
                .serverIp(serverIp)
                .build();
        return store.createVtapNetwork(VTAP_NETWORK_KEY, vtapNetwork);
    }
@Test(expected = NullPointerException.class)
    public void testCreateNullVtapNetwork() {
        target.createVtapNetwork(null, null, null);
    }