From 701ae4af67d5c611e42f7dfa4ae95face7bde32d Mon Sep 17 00:00:00 2001
From: a0666660 <69061030+a0666660@users.noreply.github.com>
Date: Sat, 3 Oct 2026 22:26:56 +0800
Subject: [PATCH] test(timezone-converter): pin hourCycle h23 in differential
 fixtures

CI ICU renders midnight as hour 24 under hour12:false for en-CA,
which Date.parse rejects; explicit h23 is deterministic across engines.
---
 .../timezone-converter.differential.test.ts                   | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/tools/timezone-converter/timezone-converter.differential.test.ts b/src/tools/timezone-converter/timezone-converter.differential.test.ts
index 054567e5..10104997 100644
--- a/src/tools/timezone-converter/timezone-converter.differential.test.ts
+++ b/src/tools/timezone-converter/timezone-converter.differential.test.ts
@@ -5,7 +5,7 @@ import { convertBetweenTimezones, listTimezones } from './timezone-converter.mod
 function getTimeZoneOffsetMs(date: Date, timeZone: string): number {
   const parts = new Intl.DateTimeFormat('en-US', {
     timeZone,
-    hour12: false,
+    hourCycle: 'h23',
     year: 'numeric',
     month: '2-digit',
     day: '2-digit',
@@ -79,7 +79,7 @@ it('A to B to A roundtrip is lossless across zone pairs', () => {
         hour: '2-digit',
         minute: '2-digit',
         second: '2-digit',
-        hour12: false,
+        hourCycle: 'h23',
       }).formatToParts(instant);
       const v = Object.fromEntries(parts.map(p => [p.type, p.value]));
       const naive = `${v.year}-${v.month}-${v.day} ${v.hour}:${v.minute}:${v.second}`;