refactor: use Time for testing

Author: kenjis

system/Helpers/date_helper.php

@@ -9,6 +9,8 @@
  * the LICENSE file that was distributed with this source code.
  */
 
+use CodeIgniter\I18n\Time;
+
 // CodeIgniter Date Helpers
 
 if (! function_exists('now')) {
@@ -25,12 +27,14 @@ function now(?string $timezone = null): int
         $timezone = empty($timezone) ? app_timezone() : $timezone;
 
         if ($timezone === 'local' || $timezone === date_default_timezone_get()) {
-            return time();
+            $time = Time::now();
+
+            return $time->getTimestamp();
         }
 
-        $datetime = new DateTime('now', new DateTimeZone($timezone));
+        $time = Time::now($timezone);
         sscanf(
-            $datetime->format('j-n-Y G:i:s'),
+            $time->format('j-n-Y G:i:s'),
             '%d-%d-%d %d:%d:%d',
             $day,
             $month,

tests/system/Helpers/DateHelperTest.php

@@ -11,6 +11,7 @@
 
 namespace CodeIgniter\Helpers;
 
+use CodeIgniter\I18n\Time;
 use CodeIgniter\Test\CIUnitTestCase;
 use DateTimeZone;
 
@@ -27,16 +28,24 @@ protected function setUp(): void
 
     public function testNowDefault()
     {
-        $this->assertCloseEnough(now(), time());  // close enough
+        Time::setTestNow('June 20, 2022', 'America/Chicago');
+
+        $this->assertSame(now(), 1_655_701_200);
+
+        Time::setTestNow();
     }
 
     public function testNowSpecific()
     {
+        Time::setTestNow('June 20, 2022', 'America/Chicago');
+
         // Chicago should be two hours ahead of Vancouver
-        $this->assertCloseEnough(
+        $this->assertSame(
             7200,
             now('America/Chicago') - now('America/Vancouver')
         );
+
+        Time::setTestNow();
     }
 
     public function testTimezoneSelectDefault()