made the assertions in the RequestTest more explicit and improved PHPDoc

src/Symfony/Component/HttpFoundation/Request.php

@@ -641,7 +641,7 @@ class Request
      * It builds a normalized query string, where keys/value pairs are alphabetized
      * and have consistent escaping.
      *
-     * @return string A normalized query string for the Request
+     * @return string|null A normalized query string for the Request
      *
      * @api
      */
@@ -923,7 +923,7 @@ class Request
      *
      * @param  array  $locales  An array of ordered available locales
      *
-     * @return string The preferred locale
+     * @return string|null The preferred locale
      *
      * @api
      */
@@ -1037,6 +1037,8 @@ class Request
      * Splits an Accept-* HTTP header.
      *
      * @param string $header  Header to split
+     *
+     * @return array Array indexed by the values of the Accept-* header in preferred order
      */
     public function splitHttpAcceptHeader($header)
     {

tests/Symfony/Tests/Component/HttpFoundation/RequestTest.php

@@ -718,8 +718,8 @@ class RequestTest extends \PHPUnit_Framework_TestCase
     public function testGetPreferredLanguage()
     {
         $request = new Request();
-        $this->assertEquals('', $request->getPreferredLanguage());
-        $this->assertEquals('', $request->getPreferredLanguage(array()));
+        $this->assertNull($request->getPreferredLanguage());
+        $this->assertNull($request->getPreferredLanguage(array()));
         $this->assertEquals('fr', $request->getPreferredLanguage(array('fr')));
         $this->assertEquals('fr', $request->getPreferredLanguage(array('fr', 'en')));
         $this->assertEquals('en', $request->getPreferredLanguage(array('en', 'fr')));
@@ -795,10 +795,10 @@ class RequestTest extends \PHPUnit_Framework_TestCase
         $this->assertEquals('html', $request->getRequestFormat());
 
         $request = new Request();
-        $this->assertEquals(null, $request->getRequestFormat(null));
+        $this->assertNull($request->getRequestFormat(null));
 
         $request = new Request();
-        $this->assertEquals(null, $request->setRequestFormat('foo'));
+        $request->setRequestFormat('foo');
         $this->assertEquals('foo', $request->getRequestFormat(null));
     }