أدلة اختبارات النموذج والمكوّن والهدف

const assert = require('node:assert/strict');
function toggle(selected, id) {
  return selected.includes(id) ? selected.filter(value => value !== id) : [...selected, id];
}
const before = Object.freeze(['w-7']);
const added = toggle(before, 'w-9');
assert.deepEqual(before, ['w-7']);
assert.deepEqual(added, ['w-7', 'w-9']);
assert.notEqual(added, before);
assert.deepEqual(toggle(added, 'w-7'), ['w-9']);
console.log('selection assertions passed');

selection assertions passed

يفحص المصدر المحفوظ ومرجعا جديدا وانتقالي العضوية. ولا يثبت إعادة عرض أصلية.

const assert = require('node:assert/strict');
function deferred() {
  let resolve;
  const promise = new Promise(done => { resolve = done; });
  return {promise, resolve};
}
async function testOrder() {
  let generation = 0;
  let visible = null;
  function load(promise) {
    const ticket = ++generation;
    return promise.then(value => { if (ticket === generation) visible = value; });
  }
  const a = deferred(), b = deferred();
  const waitingA = load(a.promise), waitingB = load(b.promise);
  b.resolve('Rivers'); await waitingB;
  a.resolve('Maps'); await waitingA;
  assert.equal(visible, 'Rivers');
  console.log('completion-order assertion passed');
}
testOrder().catch(error => { console.error(error.message); process.exitCode = 1; });

completion-order assertion passed

يتحكم حسم الوعود بالترتيب، لا افتراضات الزمن الفعلي. ويبقى العمل كله في الذاكرة.