node/test/parallel/test-http-agent-maxsockets-regress-4050.js

'use strict';
const common = require('../common');
const assert = require('assert');
const http = require('http');
const Countdown = require('../common/countdown');

const MAX_SOCKETS = 2;

const agent = new http.Agent({
  keepAlive: true,
  keepAliveMsecs: 1000,
  maxSockets: MAX_SOCKETS,
  maxFreeSockets: 2
});

const server = http.createServer(common.mustCall((req, res) => {
  res.end('hello world');
}, 6));

const countdown = new Countdown(6, common.mustCall(() => server.close()));

function get(path, callback) {
  return http.get({
    host: 'localhost',
    port: server.address().port,
    agent: agent,
    path: path
  }, callback);
}

server.listen(0, common.mustCall(() => {
  for (let i = 0; i < 6; i++) {
    const request = get('/1', common.mustCall());
    request.on('response', common.mustCall(() => {
      request.abort();
      const sockets = agent.sockets[Object.keys(agent.sockets)[0]];
      assert(sockets.length <= MAX_SOCKETS);
      countdown.dec();
    }));
  }
}));