@InvokeOnHeader(Web3jConstants.SHH_ADD_TO_GROUP)
    void shhAddToGroup(Message message) throws IOException {
        String identityAddress = message.getHeader(Web3jConstants.ADDRESS, configuration::getAddress, String.class);
        Request<?, ShhAddToGroup> request = web3j.shhAddToGroup(identityAddress);
        setRequestId(message, request);
        ShhAddToGroup response = request.send();
        boolean hasError = checkForError(message, response);
        if (!hasError) {
            message.setBody(response.addedToGroup());
        }
    }
@Test
    public void shhAddToGroupTest() throws Exception {
        ShhAddToGroup response = Mockito.mock(ShhAddToGroup.class);
        Mockito.when(mockWeb3j.shhAddToGroup(any())).thenReturn(request);
        Mockito.when(request.send()).thenReturn(response);
        Mockito.when(response.addedToGroup()).thenReturn(Boolean.TRUE);

        Exchange exchange = createExchangeWithBodyAndHeader(null, OPERATION, Web3jConstants.SHH_ADD_TO_GROUP);
        template.send(exchange);
        Boolean body = exchange.getIn().getBody(Boolean.class);
        assertTrue(body);
    }