Try to fix test

Author: Jean85

tests/Gedmo/Timestampable/TimestampableDocumentTest.php

@@ -16,6 +16,7 @@
 use Gedmo\Tests\Timestampable\Fixture\Document\Type;
 use Gedmo\Tests\Tool\BaseTestCaseMongoODM;
 use Gedmo\Timestampable\TimestampableListener;
+use MongoDB\BSON\Timestamp;
 
 /**
  * These are tests for Timestampable behavior ODM implementation
@@ -41,7 +42,11 @@ public function testTimestampable(): void
 
         $date = new \DateTime();
         $now = time();
-        $created = $article->getCreated()->getTimestamp();
+        $created = $article->getCreated();
+        if ($created instanceof Timestamp) {
+            $created = $created->getTimestamp();
+        }
+
         static::assertTrue($created > $now - 5 && $created < $now + 5); // 5 seconds interval if lag
         static::assertSame(
             $date->format('Y-m-d H:i'),