Fix call to undefined function json_last_error_message

src/Symfony/Component/Serializer/Encoder/JsonDecode.php

@@ -108,7 +108,7 @@ public function decode($data, $format, array $context = array())
         }
 
         if (JSON_ERROR_NONE !== $this->lastError = json_last_error()) {
-            throw new UnexpectedValueException(json_last_error_message());
+            throw new UnexpectedValueException(json_last_error_msg());
         }
 
         return $decodedData;

src/Symfony/Component/Serializer/Encoder/JsonEncode.php

@@ -56,7 +56,7 @@ public function encode($data, $format, array $context = array())
         $encodedJson = json_encode($data, $context['json_encode_options']);
 
         if (JSON_ERROR_NONE !== $this->lastError = json_last_error()) {
-            throw new UnexpectedValueException(json_last_error_message());
+            throw new UnexpectedValueException(json_last_error_msg());
         }
 
         return $encodedJson;

src/Symfony/Component/Serializer/Tests/Encoder/JsonDecodeTest.php

@@ -0,0 +1,44 @@
+<?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\Encoder;
+
+use Symfony\Component\Serializer\Encoder\JsonDecode;
+
+class JsonDecodeTest extends \PHPUnit_Framework_TestCase
+{
+    /** @var \Symfony\Component\Serializer\Encoder\JsonDecode */
+    private $decoder;
+
+    protected function setUp()
+    {
+        $this->decoder = new JsonDecode(true);
+    }
+
+    public function testDecodeWithValidData()
+    {
+        $json = json_encode(array(
+            'hello' => 'world',
+        ));
+        $result = $this->decoder->decode($json, 'json');
+        $this->assertEquals(array(
+            'hello' => 'world',
+        ), $result);
+    }
+
+    /**
+     * @expectedException \Symfony\Component\Serializer\Exception\UnexpectedValueException
+     */
+    public function testDecodeWithInvalidData()
+    {
+        $result = $this->decoder->decode('kaboom!', 'json');
+    }
+}