text: 'use strict';
  var common = require('../common');
  var assert = require('assert');
  var Buffer = require('buffer').Buffer;
  var dgram = require('dgram');
  
  var debug = false;
  var tests_run = 0;
  
  function pingPongTest(port, host) {
    var callbacks = 0;
    var N = 500;
    var count = 0;
  
    var server = dgram.createSocket('udp4', function(msg, rinfo) {
      if (debug) console.log('server got: ' + msg +
                             ' from ' + rinfo.address + ':' + rinfo.port);
  
      if (/PING/.exec(msg)) {
        var buf = new Buffer(4);
        buf.write('PONG');
        server.send(buf, 0, buf.length,
                    rinfo.port, rinfo.address,
                    function(err, sent) {
                      callbacks++;
                    });
      }
    });
  
    server.on('error', function(e) {
      throw e;
    });
  
    server.on('listening', function() {
      console.log('server listening on ' + port + ' ' + host);
  
      const buf = new Buffer('PING');
      const client = dgram.createSocket('udp4');
  
      client.on('message', function(msg, rinfo) {
        if (debug) console.log('client got: ' + msg +
                               ' from ' + rinfo.address + ':' + rinfo.port);
        assert.equal('PONG', msg.toString('ascii'));
  
        count += 1;
  
        if (count < N) {
          client.send(buf, 0, buf.length, port, 'localhost');
        } else {
          client.send(buf, 0, buf.length, port, 'localhost', function() {
            client.close();
          });
        }
      });
  
      client.on('close', function() {
        console.log('client has closed, closing server');
        assert.equal(N, count);
        tests_run += 1;
        server.close();
        assert.equal(N - 1, callbacks);
      });
  
      client.on('error', function(e) {
        throw e;
      });
  
      console.log('Client sending to ' + port + ', localhost ' + buf);
      client.send(buf, 0, buf.length, port, 'localhost', function(err, bytes) {
        if (err) {
          throw err;
        }
        console.log('Client sent ' + bytes + ' bytes');
      });
      count += 1;
    });
    server.bind(port, host);
  }
  
  // All are run at once, so run on different ports
  pingPongTest(common.PORT + 0, 'localhost');
  pingPongTest(common.PORT + 1, 'localhost');
  pingPongTest(common.PORT + 2);
  //pingPongTest('/tmp/pingpong.sock');
  
  process.on('exit', function() {
    assert.equal(3, tests_run);
    console.log('done');
  });
  