Example for tests for https://github.com/brightcove/hot-shots/pull/79

gistfile1.txt

"use strict";

var dgram = require('dgram');
var assert = require('assert');
var net = require('net');
var StatsD = require('../').StatsD;

/**
 * Since sampling uses random, we need to patch Math.random() to always give
 * a consistent result
 */
Math.random = function () {
  return 0.42;
};

function createTCPServer(onListening) {
  var server = net.createServer(function (socket) {
    socket.setEncoding('ascii');
    socket.on('data', function (data) {
      var metrics;
      if (data) {
        metrics = data.split('\n').filter(function (part) {
          return part !== '';
        });
        server.emit('metrics', metrics);
      }
    });
  });

  server.on('listening', function () {
    onListening(server.address());
  });

  server.listen(0, '127.0.0.1');
  return server;
}

function createUDPServer(onListening){
  var server = dgram.createSocket("udp4");
  server.on('message', function(message){
    var metrics = message.toString();
    server.emit('metrics', metrics);
  });

  server.on('listening', function(){
    onListening(server.address());
  });

  server.bind(0, '127.0.0.1');
  return server;
}

describe('StatsD', function () {
  var server;
  var statsd;

  afterEach(function () {
    // Remove it from the namespace to not fail other tests
    delete global.statsd;
    statsd = null;
  });

  describe('#globalTags TCP', function () {
    it('should not add global tags if they are not specified', function (done) {
      server = createTCPServer(function (address) {
        statsd = new StatsD({
          host: address.address,
          port: address.port,
          protocol: 'tcp'
        });
        statsd.increment('test');
      });
      server.on('metrics', function (metrics) {
        assert.equal(metrics, 'test:1|c');
        server.close();
        done();
      });
    });

    it('should add global tags if they are specified', function (done) {
      server = createTCPServer(function (address) {
        statsd = new StatsD({
          host: address.address,
          port: address.port,
          global_tags: ['gtag'],
          protocol: 'tcp'
        });
        statsd.increment('test');
      });
      server.on('metrics', function (metrics) {
        assert.equal(metrics, 'test:1|c|#gtag');
        server.close();
        done();
      });
    });

    it('should combine global tags and metric tags', function (done) {
      server = createTCPServer(function (address) {
        statsd = new StatsD({
          host: address.address,
          port: address.port,
          global_tags: ['gtag'],
          protocol: 'tcp'
        });
        statsd.increment('test', 1337, ['foo']);
      });
      server.on('metrics', function (metrics) {
        assert.equal(metrics, 'test:1337|c|#gtag,foo');
        server.close();
        done();
      });
    });
  });

  describe('#globalTags UDP', function () {
    it('should not add global tags if they are not specified', function (done) {
      server = createUDPServer(function (address) {
        console.log(address);
        statsd = new StatsD({
          host: address.address,
          port: address.port,
        });
        statsd.increment('test');
      });
      server.on('metrics', function (metrics) {
        assert.equal(metrics, 'test:1|c');
        server.close();
        done();
      });
    });

    it('should add global tags if they are specified', function (done) {
      server = createUDPServer(function (address) {
        statsd = new StatsD({
          host: address.address,
          port: address.port,
          global_tags: ['gtag'],
        });
        statsd.increment('test');
      });
      server.on('metrics', function (metrics) {
        assert.equal(metrics, 'test:1|c|#gtag');
        server.close();
        done();
      });
    });

    it('should combine global tags and metric tags', function (done) {
      server = createUDPServer(function (address) {
        statsd = new StatsD({
          host: address.address,
          port: address.port,
          global_tags: ['gtag'],
        });
        statsd.increment('test', 1337, ['foo']);
      });
      server.on('metrics', function (metrics) {
        assert.equal(metrics, 'test:1337|c|#gtag,foo');
        server.close();
        done();
      });
    });
  });

}.bind(null, StatsD));