test.js

/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at https://mozilla.org/MPL/2.0/. */

import assert from "assert";
import { getServerDate } from "./serverDate";

it(`synchronizes the time with the server`, async () => {
  const samples = [
    {
      requestDate: new Date(`2021-02-02T23:43:31.689Z`),
      responseDate: new Date(`2021-02-02T23:43:32.268Z`),
      serverDate: new Date(`2021-02-02T23:43:32.000Z`),
    },
    {
      requestDate: new Date(`2021-02-02T23:43:32.268Z`),
      responseDate: new Date(`2021-02-02T23:43:32.433Z`),
      serverDate: new Date(`2021-02-02T23:43:32.000Z`),
    },
    {
      requestDate: new Date(`2021-02-02T23:43:32.433Z`),
      responseDate: new Date(`2021-02-02T23:43:32.601Z`),
      serverDate: new Date(`2021-02-02T23:43:32.000Z`),
    },
    {
      requestDate: new Date(`2021-02-02T23:43:32.601Z`),
      responseDate: new Date(`2021-02-02T23:43:32.780Z`),
      serverDate: new Date(`2021-02-02T23:43:32.000Z`),
    },
    {
      requestDate: new Date(`2021-02-02T23:43:32.780Z`),
      responseDate: new Date(`2021-02-02T23:43:32.947Z`),
      serverDate: new Date(`2021-02-02T23:43:32.000Z`),
    },
    {
      requestDate: new Date(`2021-02-02T23:43:32.947Z`),
      responseDate: new Date(`2021-02-02T23:43:33.135Z`),
      serverDate: new Date(`2021-02-02T23:43:33.000Z`),
    },
    {
      requestDate: new Date(`2021-02-02T23:43:33.135Z`),
      responseDate: new Date(`2021-02-02T23:43:33.383Z`),
      serverDate: new Date(`2021-02-02T23:43:33.000Z`),
    },
    {
      requestDate: new Date(`2021-02-02T23:43:33.383Z`),
      responseDate: new Date(`2021-02-02T23:43:33.551Z`),
      serverDate: new Date(`2021-02-02T23:43:33.000Z`),
    },
    {
      requestDate: new Date(`2021-02-02T23:43:33.551Z`),
      responseDate: new Date(`2021-02-02T23:43:33.726Z`),
      serverDate: new Date(`2021-02-02T23:43:33.000Z`),
    },
    {
      requestDate: new Date(`2021-02-02T23:43:33.726Z`),
      responseDate: new Date(`2021-02-02T23:43:33.896Z`),
      serverDate: new Date(`2021-02-02T23:43:33.000Z`),
    },
  ];

  let currentSample = -1;

  const fetchSample = async () => {
    currentSample++;

    if (currentSample === 5) {
      throw new Error(`bad sample`);
    }

    return samples[currentSample];
  };

  assert.deepStrictEqual(await getServerDate({ fetchSample }), {
    date: new Date(`2021-02-02T23:43:32.500Z`),
    offset: 67,
    uncertainty: 582.5,
  });
});