Testing XPC Code With an Anonymous Listener using Low Level C APIs

I have implemented a XPC server using C APIs. I want to write unit tests for it. I came across the following links that use Swift APIs-

1. Testing and Debugging XPC Code With an Anonymous Listener
2. TN3113

I have tried to write anonymous listener code and the client code in the same file, using C APIs-

#include <unistd.h>
#include <syslog.h>
#include <pthread.h>
#include <stdio.h>
#include <xpc/xpc.h>
#include <xpc/connection.h>
#include <CoreFoundation/CoreFoundation.h>

static void Anon_Client_Connection_Handler(xpc_connection_t connection, xpc_object_t clientMessage)
{
    const char *description = xpc_copy_description(clientMessage);
    printf("Event received - %s\n", description);
    free((void *)description);
    xpc_type_t type = xpc_get_type(clientMessage);
    if (type == XPC_TYPE_ERROR)
    {
        if (clientMessage == XPC_ERROR_CONNECTION_INVALID)
            printf("Client_Connection_Handler received invalid connection n");
        else if (clientMessage == XPC_ERROR_TERMINATION_IMMINENT)
            printf("Client_Connection_Handler received termination notice n");
    }
    else
    {
        const char *clientMsg = xpc_dictionary_get_string(clientMessage, "message");
        printf("Received from client: %s ", clientMsg);
    }
}

static void Anon_Listener_Connection_Handler(xpc_connection_t connection)
{
    printf("Anon_Listener_Connection_Handler called, setting up event handler \n");
    xpc_connection_set_event_handler(connection, ^(xpc_object_t clientMessage) {
      printf("Processing the connection! \n");
      Anon_Client_Connection_Handler(connection, clientMessage);
    });
    xpc_connection_resume(connection);
}

int main(int argc, const char *argv[])
{
    xpc_connection_t anon_listener = xpc_connection_create(NULL, NULL);
    xpc_connection_set_event_handler(anon_listener, ^(xpc_object_t clientConnection) {
        printf("Client tried to connect \n");
        Anon_Listener_Connection_Handler(clientConnection);
    });

    xpc_connection_resume(anon_listener);
    printf("\nINFO Anonymous connection resumed");
    
    xpc_object_t anon_endpoint = xpc_endpoint_create(anon_listener);

    xpc_connection_t clientConnection = xpc_connection_create_from_endpoint(anon_endpoint);

    xpc_object_t message = xpc_dictionary_create(NULL, NULL, 0);
    xpc_dictionary_set_string(message, "message", "client's message");

    

    xpc_connection_send_message_with_reply(clientConnection, message, dispatch_get_main_queue(), ^(xpc_object_t event) {
        printf("\nINFO inside reply");
        const char *description = xpc_copy_description(event);
        printf("\nINFO %s",description);
        free((void *)description);
    });
    
    xpc_release(message);

    
    xpc_release(anon_listener);
    printf("\nINFO Releasing listener");

    xpc_release(anon_endpoint);
    printf("\nINFO Releasing endpoint");
    // dispatch_main();
    return 0;
}

and this is the output I get

INFO Anonymous connection resumed
INFO Releasing listener
INFO Releasing endpoint

I am not able to connect to the client and exchange messages. Where am I going wrong?