Allow using the library without providing a PSR-20 clock implementation

CHANGELOG.md

@@ -2,6 +2,9 @@
 
 ## [Unreleased]
 
+* The Cache can now be instantiated without providing a [PSR-20](https://www.php-fig.org/psr/psr-20/) clock implementation.
+* The library doesn't depend on the [`beste/clock` library](https://github.com/beste/clock) anymore.
+
 ## [1.0.0] - 2023-12-09
 
 Initial Release

README.md

@@ -21,10 +21,8 @@ composer require beste/in-memory-cache beste/clock
 
 ```php
 use Beste\Cache\InMemoryCache;
-use Beste\Clock\SystemClock;
 
-$clock = SystemClock::create();
-$cache = new InMemoryCache($clock);
+$cache = new InMemoryCache();
 
 $item = $cache->getItem('key');
 
@@ -42,7 +40,26 @@ assert($item->isHit() === true);
 assert($item->get() === 'value');
 ```
 
-The test suite
+You can also provide your own [PSR-20](https://www.php-fig.org/psr/psr-20/) clock implementation, for example a frozen
+clock for testing, for example from the [`beste/clock` library](https://github.com/beste/clock).
+
+```php
+use Beste\Clock\FrozenClock;
+use Beste\Cache\InMemoryCache;
+
+$clock = FrozenClock::fromUTC()
+$cache = new InMemoryCache();
+
+$item = $cache->getItem('key');
+$item->set('value')->expiresAfter(new DateInterval('PT5M'));
+$cache->save($item);
+
+$clock->setTo($clock->now()->add(new DateInterval('PT2M')));
+assert($cache->getItem('key')->isHit() === true);
+
+$clock->setTo($clock->now()->add(new DateInterval('PT5M')));
+assert($cache->getItem('key')->isHit() === false);
+```
 
 ## Running tests
 

composer.json

@@ -13,8 +13,7 @@
     "require": {
         "php": "~8.1.0 || ~8.2.0 || ~8.3.0",
         "psr/cache": "^2.0 || ^3.0",
-        "psr/clock": "^1.0",
-        "psr/clock-implementation": "^1.0"
+        "psr/clock": "^1.0"
     },
     "require-dev": {
         "beste/clock": "^3.0",
@@ -30,6 +29,9 @@
     "provide": {
         "psr/cache-implementation": "2.0 || 3.0"
     },
+    "suggest": {
+        "psr/clock-implementation": "Allows injecting a Clock, for example a frozen clock for testing"
+    },
     "autoload": {
         "psr-4": {
             "Beste\\Cache\\": "src"

src/InMemoryCache.php

@@ -2,19 +2,30 @@
 
 namespace Beste\Cache;
 
+use DateTimeImmutable;
 use Psr\Cache\CacheItemInterface;
 use Psr\Cache\CacheItemPoolInterface;
 use Psr\Clock\ClockInterface;
 
 final class InMemoryCache implements CacheItemPoolInterface
 {
+    private readonly ClockInterface $clock;
+
     /** @var array<string, CacheItemInterface> */
     private array $items;
     /** @var array<string, CacheItemInterface> */
     private array $deferredItems;
 
-    public function __construct(private readonly ClockInterface $clock)
-    {
+    public function __construct(
+        ClockInterface $clock = null
+    ) {
+        $this->clock = $clock ?? new class () implements ClockInterface {
+            public function now(): DateTimeImmutable
+            {
+                return new DateTimeImmutable();
+            }
+
+        };
         $this->items = [];
         $this->deferredItems = [];
     }

tests/InMemoryCacheTest.php

@@ -20,6 +20,20 @@ protected function setUp(): void
         $this->pool = new InMemoryCache($this->clock);
     }
 
+    public function testItWorksWithouProvidingAClock(): void
+    {
+        $pool = new InMemoryCache();
+        $item = $pool->getItem('item');
+
+        self::assertFalse($item->isHit());
+
+        $item->set('value');
+        $pool->save($item);
+
+        $item = $pool->getItem('item');
+        self::assertTrue($item->isHit());
+    }
+
     public function testItReturnsANewItem(): void
     {
         $item = $this->pool->getItem('item');