@Override
    public OpenstackVtap updateVtap(OpenstackVtap description) {
        checkNotNull(description, VTAP_DESC_NULL, "vtap");

        Set<DeviceId> txDevices = description.type().isValid(Type.VTAP_TX) ?
                getEdgeDevice(Type.VTAP_TX, description.vtapCriterion()) : ImmutableSet.of();
        Set<DeviceId> rxDevices = description.type().isValid(Type.VTAP_RX) ?
                getEdgeDevice(Type.VTAP_RX, description.vtapCriterion()) : ImmutableSet.of();

        DefaultOpenstackVtap vtap = DefaultOpenstackVtap.builder(description)
                .txDeviceIds(txDevices)
                .rxDeviceIds(rxDevices)
                .build();
        return store.updateVtap(vtap, true);
    }
@Test
    public void testUpdateNotExistingVtap() {
        assertNull(target.updateVtap(VTAP_1));
    }