test: add a test to ensure the correctness of timezone upgrades

Currently, there's no way to know if a timezone upgrade PR is correct
without building and testing the change locally. This change provides a
solution for that.

Tested in https://github.com/RaisinTen/node/pull/4.

Signed-off-by: Darshan Sen <raisinten@gmail.com>
PR-URL: https://github.com/nodejs/node/pull/45299
Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com>

.github/workflows/timezone-update.yml

@@ -36,6 +36,9 @@ jobs:
 
       - run: ./tools/update-timezone.mjs
 
+      - name: Update the expected timezone version in test
+        run: echo "${{ env.new_version }}" > test/fixtures/tz-version.txt
+
       - name: Open Pull Request
         uses: gr2m/create-or-update-pull-request-action@dc1726cbf4dd3ce766af4ec29cfb660e0125e8ee  # Create a PR or update the Action's existing PR
         env:

test/fixtures/tz-version.txt

@@ -0,0 +1 @@
+2022e

test/parallel/test-tz-version.js

@@ -0,0 +1,28 @@
+'use strict';
+
+const common = require('../common');
+
+if (!common.hasIntl) {
+  common.skip('missing Intl');
+}
+
+// Refs: https://github.com/nodejs/node/blob/1af63a90ca3a59ca05b3a12ad7dbea04008db7d9/configure.py#L1694-L1711
+if (process.config.variables.icu_path !== 'deps/icu-small') {
+  // If Node.js is configured to use its built-in ICU, it uses a strict subset
+  // of ICU formed using `tools/icu/shrink-icu-src.py`, which is present in
+  // `deps/icu-small`. It is not the same as configuring the build with
+  // `./configure --with-intl=small-icu`. The latter only uses a subset of the
+  // locales, i.e., it uses the English locale, `root,en`, by default and other
+  // locales can also be specified using the `--with-icu-locales` option.
+  common.skip('not using the icu data file present in deps/icu-small/source/data/in/icudt##l.dat.bz2');
+}
+
+const fixtures = require('../common/fixtures');
+
+// This test ensures the correctness of the automated timezone upgrade PRs.
+
+const { strictEqual } = require('assert');
+const { readFileSync } = require('fs');
+
+const expectedVersion = readFileSync(fixtures.path('tz-version.txt'), 'utf8').trim();
+strictEqual(process.versions.tz, expectedVersion);