Clock service and decorator

src/Clock/Clock.php

@@ -0,0 +1,12 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Patchlevel\EventSourcing\Clock;
+
+use DateTimeImmutable;
+
+interface Clock
+{
+    public function create(): DateTimeImmutable;
+}

src/Clock/FreezeClock.php

@@ -0,0 +1,34 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Patchlevel\EventSourcing\Clock;
+
+use DateTimeImmutable;
+
+use function sprintf;
+
+final class FreezeClock implements Clock
+{
+    public function __construct(private DateTimeImmutable $frozenDateTime)
+    {
+    }
+
+    public function update(DateTimeImmutable $frozenDateTime): void
+    {
+        $this->frozenDateTime = $frozenDateTime;
+    }
+
+    /**
+     * @param positive-int $seconds
+     */
+    public function sleep(int $seconds): void
+    {
+        $this->frozenDateTime = $this->frozenDateTime->modify(sprintf('+%s seconds', $seconds));
+    }
+
+    public function create(): DateTimeImmutable
+    {
+        return $this->frozenDateTime;
+    }
+}

src/Clock/SystemClock.php

@@ -0,0 +1,15 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Patchlevel\EventSourcing\Clock;
+
+use DateTimeImmutable;
+
+final class SystemClock implements Clock
+{
+    public function create(): DateTimeImmutable
+    {
+        return new DateTimeImmutable();
+    }
+}

src/EventBus/Decorator/RecordedOnDecorator.php

@@ -0,0 +1,20 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Patchlevel\EventSourcing\EventBus\Decorator;
+
+use Patchlevel\EventSourcing\Clock\Clock;
+use Patchlevel\EventSourcing\EventBus\Message;
+
+final class RecordedOnDecorator implements MessageDecorator
+{
+    public function __construct(private readonly Clock $clock)
+    {
+    }
+
+    public function __invoke(Message $message): Message
+    {
+        return $message->withRecordedOn($this->clock->create());
+    }
+}

src/Repository/DefaultRepository.php

@@ -4,9 +4,11 @@
 
 namespace Patchlevel\EventSourcing\Repository;
 
+use DateTimeImmutable;
 use Patchlevel\EventSourcing\Aggregate\AggregateRoot;
-use Patchlevel\EventSourcing\Clock;
+use Patchlevel\EventSourcing\Clock\SystemClock;
 use Patchlevel\EventSourcing\EventBus\Decorator\MessageDecorator;
+use Patchlevel\EventSourcing\EventBus\Decorator\RecordedOnDecorator;
 use Patchlevel\EventSourcing\EventBus\EventBus;
 use Patchlevel\EventSourcing\EventBus\Message;
 use Patchlevel\EventSourcing\Metadata\AggregateRoot\AggregateRootMetadata;
@@ -37,7 +39,7 @@ final class DefaultRepository implements Repository
     private ?SnapshotStore $snapshotStore;
     private LoggerInterface $logger;
     private AggregateRootMetadata $metadata;
-    private ?MessageDecorator $messageDecorator;
+    private MessageDecorator $messageDecorator;
 
     /**
      * @param class-string<T> $aggregateClass
@@ -54,7 +56,7 @@ public function __construct(
         $this->eventBus = $eventBus;
         $this->aggregateClass = $aggregateClass;
         $this->snapshotStore = $snapshotStore;
-        $this->messageDecorator = $messageDecorator;
+        $this->messageDecorator = $messageDecorator ??  new RecordedOnDecorator(new SystemClock());
         $this->logger = $logger ?? new NullLogger();
         $this->metadata = $aggregateClass::metadata();
     }
@@ -129,13 +131,9 @@ static function (object $event) use ($aggregate, &$playhead, $messageDecorator)
                     ->withAggregateClass($aggregate::class)
                     ->withAggregateId($aggregate->aggregateRootId())
                     ->withPlayhead(++$playhead)
-                    ->withRecordedOn(Clock::createDateTimeImmutable());
+                    ->withRecordedOn(new DateTimeImmutable());
 
-                if ($messageDecorator) {
-                    $message = $messageDecorator($message);
-                }
-
-                return $message;
+                return $messageDecorator($message);
             },
             $events
         );

src/Repository/DefaultRepositoryManager.php

@@ -5,7 +5,9 @@
 namespace Patchlevel\EventSourcing\Repository;
 
 use Patchlevel\EventSourcing\Aggregate\AggregateRoot;
+use Patchlevel\EventSourcing\Clock\SystemClock;
 use Patchlevel\EventSourcing\EventBus\Decorator\MessageDecorator;
+use Patchlevel\EventSourcing\EventBus\Decorator\RecordedOnDecorator;
 use Patchlevel\EventSourcing\EventBus\EventBus;
 use Patchlevel\EventSourcing\Metadata\AggregateRoot\AggregateRootClassNotRegistered;
 use Patchlevel\EventSourcing\Metadata\AggregateRoot\AggregateRootRegistry;
@@ -22,7 +24,7 @@ final class DefaultRepositoryManager implements RepositoryManager
     private Store $store;
     private EventBus $eventBus;
     private ?SnapshotStore $snapshotStore;
-    private ?MessageDecorator $messageDecorator;
+    private MessageDecorator $messageDecorator;
     private LoggerInterface $logger;
 
     /** @var array<class-string<AggregateRoot>, Repository> */
@@ -40,7 +42,7 @@ public function __construct(
         $this->store = $store;
         $this->eventBus = $eventBus;
         $this->snapshotStore = $snapshotStore;
-        $this->messageDecorator = $messageDecorator;
+        $this->messageDecorator = $messageDecorator ??  new RecordedOnDecorator(new SystemClock());
         $this->logger = $logger ?? new NullLogger();
     }
 

tests/Unit/Clock/FreezeClockTest.php

@@ -0,0 +1,50 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Patchlevel\EventSourcing\Tests\Unit\Clock;
+
+use DateTimeImmutable;
+use Patchlevel\EventSourcing\Clock\FreezeClock;
+use PHPUnit\Framework\TestCase;
+
+/** @covers \Patchlevel\EventSourcing\Clock\FreezeClock */
+class FreezeClockTest extends TestCase
+{
+    public function testCreateDateTimeImmutableWithFrozenClock(): void
+    {
+        $current = new DateTimeImmutable();
+        $clock = new FreezeClock($current);
+
+        $new = $clock->create();
+
+        self::assertSame($current, $new);
+    }
+
+    public function testSleep(): void
+    {
+        $date1 = new DateTimeImmutable();
+        $clock = new FreezeClock($date1);
+        $clock->sleep(1);
+        $date2 = $clock->create();
+
+        $diff = $date1->diff($date2);
+
+        self::assertSame(1, $diff->s);
+    }
+
+    public function testReFreeze(): void
+    {
+        $date1 = new DateTimeImmutable();
+        $clock = new FreezeClock($date1);
+        $new1 = $clock->create();
+
+        $date2 = new DateTimeImmutable();
+        $clock->update($date2);
+        $new2 = $clock->create();
+
+        self::assertSame($date1, $new1);
+        self::assertSame($date2, $new2);
+        self::assertNotSame($new1, $new2);
+    }
+}

tests/Unit/Clock/SystemClockTest.php

@@ -0,0 +1,23 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Patchlevel\EventSourcing\Tests\Unit\Clock;
+
+use DateTimeImmutable;
+use Patchlevel\EventSourcing\Clock\SystemClock;
+use PHPUnit\Framework\TestCase;
+
+/** @covers \Patchlevel\EventSourcing\Clock\SystemClock */
+class SystemClockTest extends TestCase
+{
+    public function testCreateDateTimeImmutable(): void
+    {
+        $before = new DateTimeImmutable();
+        $date = (new SystemClock())->create();
+        $after = new DateTimeImmutable();
+
+        self::assertGreaterThanOrEqual($before, $date);
+        self::assertLessThanOrEqual($after, $date);
+    }
+}