@Override
    public boolean isValid() {
        return hasOnlyFields(INGRESS_VLAN, EGRESS_VLAN, EGRESS_INNER_VLAN) &&
                ingressVlan() != null && egressVlan() != null && egressInnerVlan() != null;
    }
@Test
    public void isValid() throws Exception {
        assertTrue(config.isValid());
        assertFalse(invalidConfig.isValid());
        assertTrue(configForInnerVlan.isValid());
        assertFalse(invalidConfigForInnerVlan.isValid());
    }