created test case to reproduce error

tests/Doctrine/Tests/ORM/Functional/Ticket/DDC3103Test.php

@@ -0,0 +1,46 @@
+<?php
+
+namespace Doctrine\Tests\ORM\Functional\Ticket;
+
+use Doctrine\ORM\Mapping\ClassMetadata;
+
+/**
+ * @group DDC-3103
+ */
+class DDC3103Test extends \Doctrine\Tests\OrmFunctionalTestCase
+{
+    public function testIssue()
+    {
+        $className = __NAMESPACE__ . '\\DDC3103ArticleId';
+        $classMetadata = new ClassMetadata($className);
+
+        $this->createAnnotationDriver()->loadMetadataForClass($className, $classMetadata);
+
+        $this->assertTrue(
+            $classMetadata->isEmbeddedClass,
+            'The isEmbeddedClass property should be true from the mapping data.'
+        );
+
+        $serialized = serialize($classMetadata);
+        $classMetadata = unserialize($serialized);
+
+        $this->assertTrue(
+            $classMetadata->isEmbeddedClass,
+            'The isEmbeddedClass property should still be true after serialization and unserialization.'
+        );
+    }
+}
+
+/**
+ * @Embeddable
+ */
+class DDC3103ArticleId
+{
+    /**
+     * @var string
+     * @Column(name="name", type="string", length=255)
+     */
+    protected $nameValue;
+}
+
+