From 28bb6af2817afe8864aed02024899615987eec57 Mon Sep 17 00:00:00 2001
From: Josh Marshall <josh@jmarshall.com.au>
Date: Fri, 3 Apr 2026 14:40:16 +1000
Subject: [PATCH] Demonstrate addMinutes() across DST transition adds an hour

---
 .../DateTime/DaylightSavingsAddTest.php       | 36 +++++++++++++++++++
 1 file changed, 36 insertions(+)
 create mode 100644 tests/TestCase/DateTime/DaylightSavingsAddTest.php

diff --git a/tests/TestCase/DateTime/DaylightSavingsAddTest.php b/tests/TestCase/DateTime/DaylightSavingsAddTest.php
new file mode 100644
index 0000000..15bbe82
--- /dev/null
+++ b/tests/TestCase/DateTime/DaylightSavingsAddTest.php
@@ -0,0 +1,36 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * Copyright (c) Cake Software Foundation, Inc. (https://cakefoundation.org)
+ *
+ * Licensed under The MIT License
+ * Redistributions of files must retain the above copyright notice.
+ *
+ * @copyright     Copyright (c) Cake Software Foundation, Inc. (https://cakefoundation.org)
+ * @copyright     Copyright (c) Brian Nesbitt <brian@nesbot.com>
+ * @link          https://cakephp.org CakePHP(tm) Project
+ * @license       https://www.opensource.org/licenses/mit-license.php MIT License
+ */
+
+namespace Cake\Chronos\Test\TestCase\DateTime;
+
+use Cake\Chronos\Chronos;
+use Cake\Chronos\Test\TestCase\TestCase;
+
+class DaylightSavingsAddTest extends TestCase
+{
+    public function testDayLightSavingsTransition(): void
+    {
+        // Australia/Melbourne changes out of daylight savings 5th April 2026
+        $time = Chronos::parse('2026-04-05 09:00:00', 'Australia/Melbourne');
+
+        $this->assertSame('2026-04-05T09:00:00+10:00', $time->toIso8601String());
+        $this->assertSame('2026-04-05T00:00:00+11:00', $time->startOfDay()->toIso8601String());
+
+        $this->assertSame(600, $time->diffInMinutes($time->startOfDay()));
+
+        $this->assertSame('2026-04-05T09:00:00+10:00', $time->startOfDay()->addMinutes(600)->toIso8601String());
+    }
+}