node/test/parallel/test-timers-ordering.js

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

const Timer = process.binding('timer_wrap').Timer;
const N = 30;

let last_i = 0;
let last_ts = 0;

function f(i) {
  if (i <= N) {
    // check order
    assert.strictEqual(i, last_i + 1, `order is broken: ${i} != ${last_i} + 1`);
    last_i = i;

    // check that this iteration is fired at least 1ms later than the previous
    const now = Timer.now();
    console.log(i, now);
    assert(now >= last_ts + 1,
           `current ts ${now} < prev ts ${last_ts} + 1`);
    last_ts = now;

    // schedule next iteration
    setTimeout(f, 1, i + 1);
  }
}
f(1);