[Clock] Add ClockAwareTrait to help write time-sensitive classes

Author: nicolas-grekas

CHANGELOG.md

@@ -1,6 +1,11 @@
 CHANGELOG
 =========
 
+6.3
+---
+
+ * Add `ClockAwareTrait` to help write time-sensitive classes
+
 6.2
 ---
 

ClockAwareTrait.php

@@ -0,0 +1,36 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <[email protected]>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Clock;
+
+use Psr\Clock\ClockInterface;
+use Symfony\Contracts\Service\Attribute\Required;
+
+/**
+ * A trait to help write time-sensitive classes.
+ *
+ * @author Nicolas Grekas <[email protected]>
+ */
+trait ClockAwareTrait
+{
+    private readonly ClockInterface $clock;
+
+    #[Required]
+    public function setClock(ClockInterface $clock): void
+    {
+        $this->clock = $clock;
+    }
+
+    protected function now(): \DateTimeImmutable
+    {
+        return ($this->clock ??= new NativeClock())->now();
+    }
+}

Tests/ClockAwareTraitTest.php

@@ -0,0 +1,40 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <[email protected]>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Clock\Tests;
+
+use PHPUnit\Framework\TestCase;
+use Symfony\Component\Clock\ClockAwareTrait;
+use Symfony\Component\Clock\MockClock;
+
+class ClockAwareTraitTest extends TestCase
+{
+    public function testTrait()
+    {
+        $sut = new class() {
+            use ClockAwareTrait {
+                now as public;
+            }
+        };
+
+        $this->assertInstanceOf(\DateTimeImmutable::class, $sut->now());
+
+        $clock = new MockClock();
+        $sut = new $sut();
+        $sut->setClock($clock);
+
+        $ts = $sut->now()->getTimestamp();
+        $this->assertEquals($clock->now(), $sut->now());
+        $clock->sleep(1);
+        $this->assertEquals($clock->now(), $sut->now());
+        $this->assertSame(1.0, round($sut->now()->getTimestamp() - $ts, 1));
+    }
+}