node/test/parallel/test-tls-ecdh.js

'use strict';
const common = require('../common');

if (!common.hasCrypto) {
  common.skip('missing crypto');
  return;
}
const assert = require('assert');
const tls = require('tls');

const exec = require('child_process').exec;
const fs = require('fs');

const options = {
  key: fs.readFileSync(common.fixturesDir + '/keys/agent2-key.pem'),
  cert: fs.readFileSync(common.fixturesDir + '/keys/agent2-cert.pem'),
  ciphers: '-ALL:ECDHE-RSA-AES128-SHA256',
  ecdhCurve: 'prime256v1'
};

const reply = 'I AM THE WALRUS'; // something recognizable

const server = tls.createServer(options, common.mustCall(function(conn) {
  conn.end(reply);
}));

server.listen(0, '127.0.0.1', common.mustCall(function() {
  let cmd = '"' + common.opensslCli + '" s_client -cipher ' + options.ciphers +
            ` -connect 127.0.0.1:${this.address().port}`;

  // for the performance and stability issue in s_client on Windows
  if (common.isWindows)
    cmd += ' -no_rand_screen';

  exec(cmd, common.mustCall(function(err, stdout, stderr) {
    assert.ifError(err);
    assert(stdout.includes(reply));
    server.close();
  }));
}));