diff --git a/core/modules/rest/src/Tests/RESTTestBase.php b/core/modules/rest/src/Tests/RESTTestBase.php
index d9c4607..71b1a08 100644
--- a/core/modules/rest/src/Tests/RESTTestBase.php
+++ b/core/modules/rest/src/Tests/RESTTestBase.php
@@ -73,13 +73,11 @@ protected function setUp() {
    *   The body for POST and PUT.
    * @param string $mime_type
    *   The MIME type of the transmitted content.
-   * @param array $request_headers
-   *   Some additional request headers.
    *
    * @return string
    *   The content returned from the request.
    */
-  protected function httpRequest($url, $method, $body = NULL, $mime_type = NULL, $request_headers = []) {
+  protected function httpRequest($url, $method, $body = NULL, $mime_type = NULL) {
     if (!isset($mime_type)) {
       $mime_type = $this->defaultMimeType;
     }
@@ -120,11 +118,10 @@ protected function httpRequest($url, $method, $body = NULL, $mime_type = NULL, $
           CURLOPT_POSTFIELDS => $body,
           CURLOPT_URL => $url,
           CURLOPT_NOBODY => FALSE,
-          CURLOPT_HTTPHEADER => array_merge(
-            array(
+          CURLOPT_HTTPHEADER => array(
             'Content-Type: ' . $mime_type,
             'X-CSRF-Token: ' . $token,
-          ), $request_headers),
+          ),
         );
         break;
 
@@ -176,9 +173,6 @@ protected function httpRequest($url, $method, $body = NULL, $mime_type = NULL, $
 
     $this->verbose($method . ' request to: ' . $url .
       '<hr />Code: ' . curl_getinfo($this->curlHandle, CURLINFO_HTTP_CODE) .
-      '<hr />Request headers: ' . nl2br(print_r($curl_options[CURLOPT_HTTPHEADER], TRUE)) .
-      '<hr />Extra headers: ' . nl2br(print_r($request_headers, TRUE)) .
-      '<hr />Request body: ' . nl2br(print_r($body, TRUE)) .
       '<hr />Response headers: ' . nl2br(print_r($headers, TRUE)) .
       '<hr />Response body: ' . $this->responseBody);
 
diff --git a/core/modules/user/src/Controller/UserLoginController.php b/core/modules/user/src/Controller/UserLoginController.php
index a8eddc1..f25b07e 100644
--- a/core/modules/user/src/Controller/UserLoginController.php
+++ b/core/modules/user/src/Controller/UserLoginController.php
@@ -15,6 +15,9 @@
 use Symfony\Component\HttpFoundation\Response;
 use Symfony\Component\HttpKernel\Exception\BadRequestHttpException;
 
+/**
+ * Provides controllers for login, login status and logout.
+ */
 class UserLoginController extends ControllerBase implements ContainerInjectionInterface {
 
   /**
diff --git a/core/modules/user/tests/src/Functional/UserLoginHttpTest.php b/core/modules/user/tests/src/Functional/UserLoginHttpTest.php
index 4c865fd..a7335be 100644
--- a/core/modules/user/tests/src/Functional/UserLoginHttpTest.php
+++ b/core/modules/user/tests/src/Functional/UserLoginHttpTest.php
@@ -7,6 +7,11 @@
 use Drupal\user\Controller\UserLoginController;
 use GuzzleHttp\Cookie\CookieJar;
 
+/**
+ * Tests login via direct HTTP.
+ *
+ * @group user
+ */
 class UserLoginHttpTest extends BrowserTestBase {
 
   /**
@@ -14,12 +19,26 @@ class UserLoginHttpTest extends BrowserTestBase {
    */
   protected $cookies;
 
+  /**
+   * {@inheritdoc}
+   */
   protected function setUp() {
     parent::setUp();
 
     $this->cookies = new CookieJar();
   }
 
+  /**
+   * Executes a login HTTP request.
+   *
+   * @param string $name
+   *   The username.
+   * @param $pass
+   *   The user password.
+   *
+   * @return \Psr\Http\Message\ResponseInterface
+   *   The HTTP response.
+   */
   protected function loginRequest($name, $pass) {
     $user_login_url = Url::fromRoute('user.login.json')
       ->setRouteParameter('_format', 'json')