private void removeSubscriberIndexes(Service service, String clientId) {
        Set<String> clientIds = subscriberIndexes.get(service);
        if (clientIds == null) {
            return;
        }
        clientIds.remove(clientId);
        if (clientIds.isEmpty()) {
            subscriberIndexes.remove(service);
        }
    }
@Test
    void testRemoveSubscriberIndexes() throws NoSuchMethodException, InvocationTargetException, IllegalAccessException {
        String clientId = "clientId";
        Class<ClientServiceIndexesManager> clientServiceIndexesManagerClass = ClientServiceIndexesManager.class;
        Method removeSubscriberIndexes = clientServiceIndexesManagerClass.getDeclaredMethod("removeSubscriberIndexes", Service.class,
                String.class);
        removeSubscriberIndexes.setAccessible(true);
        removeSubscriberIndexes.invoke(clientServiceIndexesManager, service, clientId);
        
        Collection<String> allClientsSubscribeService = clientServiceIndexesManager.getAllClientsSubscribeService(service);
        
        assertNotNull(allClientsSubscribeService);
        assertEquals(1, allClientsSubscribeService.size());
    }