Close #1

The methods set, expiresAt and expiresAfter of NullCacheItem must return the item itself.

src/NullCacheItem.php

@@ -48,20 +48,23 @@ public function isHit()
      */
     public function set($value)
     {
+        return $this;
     }
 
     /**
      * @inheritDoc
      */
     public function expiresAt($expiration)
     {
+        return $this;
     }
 
     /**
      * @inheritDoc
      */
     public function expiresAfter($time)
     {
+        return $this;
     }
 
 }

tests/NullCacheItemTest.php

@@ -0,0 +1,71 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Metasyntactical\Psr\Cache;
+
+use DateInterval;
+use DateTime;
+use DateTimeImmutable;
+use DateTimeInterface;
+use DateTimeZone;
+use PHPUnit\Framework\Attributes\DataProvider;
+use PHPUnit\Framework\TestCase;
+use Traversable;
+
+class NullCacheItemTest extends TestCase
+{
+    public function testGetKey(): void
+    {
+        $object = new NullCacheItem('key');
+        self::assertSame('key', $object->getKey());
+    }
+
+    public function testGet(): void
+    {
+        $object = new NullCacheItem('key');
+        self::assertEquals(null, $object->get());
+    }
+
+    public function testIsHit(): void
+    {
+        $object = new NullCacheItem('key');
+        self::assertFalse($object->isHit());
+    }
+
+    public function testSet(): void
+    {
+        $object = new NullCacheItem('key');
+        self::assertSame($object, $object->set('value'));
+    }
+
+    #[DataProvider('provideExpiresAt')]
+    public function testExpiresAt(
+        DateTimeInterface|null $value,
+    ): void {
+        $object = new NullCacheItem('key');
+        self::assertSame($object, $object->expiresAt($value));
+    }
+
+    public static function provideExpiresAt(): Traversable
+    {
+        yield 'null' => ['value' => null];
+        yield 'DateTime' => ['value' => DateTime::createFromFormat('Y-m-d', '2024-03-12', new DateTimeZone('UTC'))];
+        yield 'DateTimeImmutable' => ['value' => DateTimeImmutable::createFromFormat('Y-m-d', '2024-03-12', new DateTimeZone('UTC'))];
+    }
+
+    #[DataProvider('provideExpiresAfter')]
+    public function testExpiresAfter(
+        DateInterval|int|null $value,
+    ): void {
+        $object = new NullCacheItem('key');
+        self::assertSame($object, $object->expiresAfter($value));
+    }
+
+    public static function provideExpiresAfter(): Traversable
+    {
+        yield 'null' => ['value' => null];
+        yield 'int' => ['value' => 42];
+        yield 'DateIterval' => ['value' => DateInterval::createFromDateString('1 day')];
+    }
+}