Hotfix/Initialize string format when wakes DateTimeValue up

* Initialize string format when wakes DateTimeValue up
* Create test to cover the case

Co-authored-by: Dmytro Zasiadko <dmytro@2amigos.us>

Author: segoddnja

src/Domain/ValueObjects/DateTimeValue.php

@@ -31,9 +31,20 @@ class DateTimeValue extends CarbonImmutable implements ValueObject
     public function __construct($time = null, $tz = null)
     {
         parent::__construct($time, $tz);
+        $this->initializeDefaultStringFormat();
+    }
+
+    private function initializeDefaultStringFormat(): void
+    {
         $this->settings(['toStringFormat' => 'c']);
     }
 
+    public function __wakeup()
+    {
+        parent::__wakeup();
+        $this->initializeDefaultStringFormat();
+    }
+
     /**
      * Return the value as string.
      *

tests/Domain/ValueObjects/DateTimeValueTest.php

@@ -0,0 +1,24 @@
+<?php
+
+declare(strict_types=1);
+
+namespace OtherCode\ComplexHeart\Tests\Domain\ValueObjects;
+
+use Mockery\Adapter\Phpunit\MockeryTestCase;
+use OtherCode\ComplexHeart\Domain\ValueObjects\DateTimeValue;
+
+/**
+ * Class DateTimeValueTest
+ * @author Dmytro <dmytro@2amigos.us>
+ * @package OtherCode\ComplexHeart\Tests\Domain\ValueObjects
+ */
+class DateTimeValueTest extends MockeryTestCase
+{
+    public function testShouldInitializeStringFormatWhenWakesUp(): void
+    {
+        $instance = new DateTimeValue();
+        $serialized = serialize($instance);
+        $wakedUp = unserialize($serialized);
+        $this->assertSame($instance->__toString(), $wakedUp->__toString());
+    }
+}