diff --git a/core/modules/simpletest/tests/common.test b/core/modules/simpletest/tests/common.test
index 6cc159b..49175cd 100644
--- a/core/modules/simpletest/tests/common.test
+++ b/core/modules/simpletest/tests/common.test
@@ -933,7 +933,8 @@ class DrupalHTTPRequestTestCase extends DrupalWebTestCase {
   }
 
   function setUp() {
-    parent::setUp('system_test');
+    parent::setUp('system_test', 'locale');
+    $this->language = 'en';
   }
 
   function testDrupalHTTPRequest() {
@@ -1030,6 +1031,36 @@ class DrupalHTTPRequestTestCase extends DrupalWebTestCase {
     $multiple_redirect_3 = drupal_http_request(url('system-test/multiple-redirects/3', array('absolute' => TRUE)), array('max_redirects' => 3));
     $this->assertEqual($multiple_redirect_3->redirect_url, $multiple_redirect_final_url, t('redirect_url contains the final redirection location after 3 redirects.'));
   }
+
+  /**
+   * Test HTTP headers of Drupal request.
+   */
+  function testDrupalHTTPRequestHeaders() {
+    // Add a new language and optionally set it as default.
+    require_once DRUPAL_ROOT . '/core/includes/locale.inc';
+
+    $request = drupal_http_request(url('<front>', array('absolute' => TRUE)));
+    $this->assertEqual($request->headers['content-language'], 'en', t('content-language HTTP header is English.'));
+
+    // Set French as a default language
+    $language = (object) array(
+      'language' => 'fr',
+      'name' => 'French',
+      'default' => 'fr',
+    );
+    locale_language_save($language);
+
+    // Make sure language default is initiliazed correctly.
+    drupal_language_initialize();
+
+    // Get site's default language.
+    $default_language = language_default();
+
+    $this->assertEqual($default_language->language, 'fr', t('Default language is French.'));
+
+    $request = drupal_http_request(url('<front>', array('absolute' => TRUE)));
+    $this->assertEqual($request->headers['content-language'], 'fr', t('content-language HTTP header is French.'));
+  }
 }
 
 /**