@Test
public void testSubscribeIfUrlNull() throws Exception {

    Assertions.assertThrows(IllegalArgumentException.class, () -> {
        final AtomicReference<Boolean> notified = new AtomicReference<Boolean>(false);
        NotifyListener listener = urls -> notified.set(Boolean.TRUE);
        URL url = new URL("dubbo", "192.168.0.1", 2200);
        abstractRegistry.subscribe(null, listener);
        Assertions.fail("subscribe url == null");
    });
}