diff --git a/tests/mimetype/guesser_test.php b/tests/mimetype/guesser_test.php
index 3728961460..6484606210 100644
--- a/tests/mimetype/guesser_test.php
+++ b/tests/mimetype/guesser_test.php
@@ -7,20 +7,32 @@
 *
 */
 
+namespace phpbb\mimetype;
+
 require_once dirname(__FILE__) . '/null_guesser.php';
 require_once dirname(__FILE__) . '/incorrect_guesser.php';
 
-class phpbb_mimetype_guesser_test extends phpbb_test_case
+function function_exists($name)
 {
+	return guesser_test::$function_exists;
+}
+
+class guesser_test extends \phpbb_test_case
+{
+	public static $function_exists = true;
+
 	public function setUp()
 	{
+		global $phpbb_root_path;
+
 		$guessers = array(
-			new Symfony\Component\HttpFoundation\File\MimeType\FileinfoMimeTypeGuesser(),
-			new Symfony\Component\HttpFoundation\File\MimeType\FileBinaryMimeTypeGuesser(),
+			new \Symfony\Component\HttpFoundation\File\MimeType\FileinfoMimeTypeGuesser(),
+			new \Symfony\Component\HttpFoundation\File\MimeType\FileBinaryMimeTypeGuesser(),
 		);
 		$this->guesser = new \phpbb\mimetype\guesser($guessers);
 		$this->path = dirname(__FILE__);
 		$this->jpg_file = $this->path . '/fixtures/jpg';
+		$this->phpbb_root_path = $phpbb_root_path;
 	}
 
 	public function data_guess_files()
@@ -80,4 +92,37 @@ class phpbb_mimetype_guesser_test extends phpbb_test_case
 	{
 		$guesser = new \phpbb\mimetype\guesser($guessers);
 	}
+
+	public function data_content_guesser()
+	{
+		return array(
+			array(
+				array(
+					'image/jpeg',
+					'image/jpeg',
+				),
+				false,
+			),
+			array(
+				array(
+					'application/octet-stream',
+					'image/jpeg',
+				),
+				true,
+			),
+		);
+	}
+
+	/**
+	* @dataProvider data_content_guesser
+	*/
+	public function test_content_guesser($expected, $overload = false)
+	{
+		self::$function_exists = ($overload) ? false : true;
+		$guesser = new \phpbb\mimetype\guesser(array(new \phpbb\mimetype\content_guesser($this->phpbb_root_path, new \phpbb\php\ini)));
+		$this->assertEquals($expected[0], $guesser->guess($this->jpg_file));
+		@copy($this->jpg_file, $this->jpg_file . '.jpg');
+		$this->assertEquals($expected[1], $guesser->guess($this->jpg_file . '.jpg'));
+		@unlink($this->jpg_file . '.jpg');
+	}
 }