diff --git a/core/modules/serialization/tests/Drupal/serialization/Tests/Encoder/JsonEncoderTest.php b/core/modules/serialization/tests/Drupal/serialization/Tests/Encoder/JsonEncoderTest.php
new file mode 100644
index 0000000..89fd8b5
--- /dev/null
+++ b/core/modules/serialization/tests/Drupal/serialization/Tests/Encoder/JsonEncoderTest.php
@@ -0,0 +1,34 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\serialization\Tests\Encoder\JsonEncoderTest.
+ */
+
+namespace Drupal\serialization\Tests\Encoder;
+
+use Drupal\serialization\Encoder\JsonEncoder;
+use Drupal\Tests\UnitTestCase;
+
+class JsonEncoderTest extends UnitTestCase {
+
+  public static function getInfo() {
+    return array(
+      'name' => 'JsonEncoderTest',
+      'description' => 'Tests the JsonEncoder class.',
+      'group' => 'Serialization',
+    );
+  }
+
+  /**
+   * Tests the supportsEncoding() method.
+   */
+  public function testSupportsEncoding() {
+    $encoder = new JsonEncoder();
+
+    $this->assertTrue($encoder->supportsEncoding('json'));
+    $this->assertTrue($encoder->supportsEncoding('ajax'));
+    $this->assertFalse($encoder->supportsEncoding('xml'));
+  }
+
+}