[Serializer] Fix CustomNormalizer supportsDenormalization interface check.

src/Symfony/Component/Serializer/Normalizer/CustomNormalizer.php

@@ -59,6 +59,6 @@ class CustomNormalizer extends SerializerAwareNormalizer implements NormalizerIn
     {
         $class = new \ReflectionClass($type);
 
-        return $class->isSubclassOf('Symfony\Component\Serializer\Normalizer\NormalizableInterface');
+        return $class->isSubclassOf('Symfony\Component\Serializer\Normalizer\DenormalizableInterface');
     }
 }

src/Symfony/Component/Serializer/Tests/Fixtures/DenormalizableDummy.php

@@ -0,0 +1,25 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Serializer\Tests\Fixtures;
+
+use Symfony\Component\Serializer\Normalizer\DenormalizableInterface;
+use Symfony\Component\Serializer\Normalizer\DenormalizerInterface;
+
+class DenormalizableDummy implements DenormalizableInterface
+{
+
+    function denormalize(DenormalizerInterface $denormalizer, $data, $format = null)
+    {
+
+    }
+
+}

src/Symfony/Component/Serializer/Tests/Fixtures/Dummy.php

@@ -12,10 +12,11 @@
 namespace Symfony\Component\Serializer\Tests\Fixtures;
 
 use Symfony\Component\Serializer\Normalizer\NormalizableInterface;
+use Symfony\Component\Serializer\Normalizer\DenormalizableInterface;
 use Symfony\Component\Serializer\Normalizer\NormalizerInterface;
 use Symfony\Component\Serializer\Normalizer\DenormalizerInterface;
 
-class Dummy implements NormalizableInterface
+class Dummy implements NormalizableInterface, DenormalizableInterface
 {
     public $foo;
     public $bar;

src/Symfony/Component/Serializer/Tests/Fixtures/NormalizableTraversableDummy.php

@@ -12,10 +12,11 @@
 namespace Symfony\Component\Serializer\Tests\Fixtures;
 
 use Symfony\Component\Serializer\Normalizer\NormalizableInterface;
+use Symfony\Component\Serializer\Normalizer\DenormalizableInterface;
 use Symfony\Component\Serializer\Normalizer\NormalizerInterface;
 use Symfony\Component\Serializer\Normalizer\DenormalizerInterface;
 
-class NormalizableTraversableDummy extends TraversableDummy implements NormalizableInterface
+class NormalizableTraversableDummy extends TraversableDummy implements NormalizableInterface, DenormalizableInterface
 {
     public function normalize(NormalizerInterface $normalizer, $format = null)
     {

src/Symfony/Component/Serializer/Tests/Normalizer/CustomNormalizerTest.php

@@ -53,5 +53,6 @@ class CustomNormalizerTest extends \PHPUnit_Framework_TestCase
     {
         $this->assertTrue($this->normalizer->supportsDenormalization(array(), 'Symfony\Component\Serializer\Tests\Fixtures\ScalarDummy'));
         $this->assertFalse($this->normalizer->supportsDenormalization(array(), 'stdClass'));
+        $this->assertTrue($this->normalizer->supportsDenormalization(array(), 'Symfony\Component\Serializer\Tests\Fixtures\DenormalizableDummy'));
     }
 }