Implemented Doctrine serializer

phpunit.xml.dist

@@ -18,10 +18,6 @@
     </testsuite>
   </testsuites>
 
-  <logging>
-    <log type="coverage-text" target="php://stdout"/>
-  </logging>
-
   <filter>
     <whitelist>
       <directory suffix=".php">./src</directory>

src/TreeHouse/Queue/Message/Serializer/DoctrineSerializer.php

@@ -16,8 +16,26 @@ public function __construct(ManagerRegistry $doctrine)
      */
     public function serialize($value)
     {
+        return json_encode($this->getIdentifierValues($value));
+    }
+
+    /**
+     * @param $value
+     *
+     * @return array
+     */
+    protected function getIdentifierValues($value)
+    {
+        // if a raw identifier is passed, return it in an array.
+        // this would be the same if we passed in an object with that id
         if (is_numeric($value)) {
-            return $value;
+            return [$value];
         }
+
+        $class    = get_class($value);
+        $metadata = $this->doctrine->getManager()->getClassMetadata($class);
+        $id       = $metadata->getIdentifierValues($value);
+
+        return array_values($id);
     }
 }

tests/TreeHouse/Queue/Tests/Message/Serializer/DoctrineSerializerTest.php

@@ -3,6 +3,9 @@
 namespace TreeHouse\Queue\Tests\Message\Serializer;
 
 use Doctrine\Common\Persistence\ManagerRegistry;
+use Doctrine\Common\Persistence\Mapping\ClassMetadata;
+use Doctrine\Common\Persistence\ObjectManager;
+use Doctrine\Tests\Common\Persistence\ObjectManagerDecoratorTest;
 use TreeHouse\Queue\Message\Serializer\DoctrineSerializer;
 
 class DoctrineSerializerTest extends \PHPUnit_Framework_TestCase
@@ -31,16 +34,42 @@ public function testSerialize($value, $expected)
     public function getTestData()
     {
         return [
-            [2, 2], // assume integers are identifiers
-            // TODO test with actual entity
+            [2, "[2]"], // assume integers are identifiers
+            [new EntityMock(1234), "[1234]"]
         ];
     }
 
     protected function setUp()
     {
-        $this->doctrine = $this
-            ->getMockBuilder(ManagerRegistry::class)
-            ->getMock()
+        $meta = $this->getMockBuilder(ClassMetadata::class)->getMock();
+        $meta->expects($this->any())->method('getIdentifierValues')->will($this->returnCallback(function ($value) {
+            /** @var EntityMock $value */
+            return ['id' => $value->getId()];
+        }));
+
+        $manager = $this->getMockBuilder(ObjectManager::class)->getMock();
+        $manager->expects($this->any())->method('getClassMetadata')->will($this->returnValue($meta));
+
+        $this->doctrine = $this->getMockBuilder(ManagerRegistry::class)->getMock();
+        $this->doctrine
+            ->expects($this->any())
+            ->method('getManager')
+            ->will($this->returnValue($manager))
         ;
     }
 }
+
+class EntityMock
+{
+    private $id;
+
+    public function __construct($id)
+    {
+        $this->id = $id;
+    }
+
+    public function getId()
+    {
+        return $this->id;
+    }
+}