diff --git a/core/modules/history/src/Tests/HistoryTest.php b/core/modules/history/src/Tests/HistoryTest.php
index 17bba34..3f001b7 100644
--- a/core/modules/history/src/Tests/HistoryTest.php
+++ b/core/modules/history/src/Tests/HistoryTest.php
@@ -3,7 +3,10 @@
 namespace Drupal\history\Tests;
 
 use Drupal\Component\Serialization\Json;
+use Drupal\Core\Url;
 use Drupal\simpletest\WebTestBase;
+use Symfony\Component\Serializer\Encoder\JsonEncoder;
+use Symfony\Component\Serializer\Serializer;
 
 /**
  * Tests the History endpoints.
@@ -33,14 +36,31 @@ class HistoryTest extends WebTestBase {
    */
   protected $testNode;
 
+  /**
+   * The Guzzle HTTP client.
+   *
+   * @var \GuzzleHttp\Client;
+   */
+  protected $client;
+
+  /**
+   * The serializer.
+   *
+   * @var \Symfony\Component\Serializer\Serializer
+   */
+  protected $serializer;
+
   protected function setUp() {
     parent::setUp();
 
     $this->drupalCreateContentType(array('type' => 'page', 'name' => 'Basic page'));
-
     $this->user = $this->drupalCreateUser(array('create page content', 'access content'));
     $this->drupalLogin($this->user);
     $this->testNode = $this->drupalCreateNode(array('type' => 'page', 'uid' => $this->user->id()));
+    $this->client = \Drupal::service('http_client_factory')
+      ->fromOptions(['config/curl' => [CURLOPT_TIMEOUT => 10]]);
+    $encoders = [new JsonEncoder()];
+    $this->serializer = new Serializer([], $encoders);
   }
 
   /**
@@ -49,35 +69,25 @@ protected function setUp() {
    * @param array $node_ids
    *   An array of node IDs.
    *
-   * @return string
-   *   The response body.
+   * @return \Psr\Http\Message\ResponseInterface
+   *   The response object.
    */
   protected function getNodeReadTimestamps(array $node_ids) {
     // Build POST values.
     $post = array();
-    for ($i = 0; $i < count($node_ids); $i++) {
-      $post['node_ids[' . $i . ']'] = $node_ids[$i];
-    }
-
-    // Serialize POST values.
-    foreach ($post as $key => $value) {
-      // Encode according to application/x-www-form-urlencoded
-      // Both names and values needs to be urlencoded, according to
-      // http://www.w3.org/TR/html4/interact/forms.html#h-17.13.4.1
-      $post[$key] = urlencode($key) . '=' . urlencode($value);
-    }
-    $post = implode('&', $post);
+    $post['node_ids'] = $node_ids;
 
     // Perform HTTP request.
-    return $this->curlExec(array(
-      CURLOPT_URL => \Drupal::url('history.get_last_node_view', array(), array('absolute' => TRUE)),
-      CURLOPT_POST => TRUE,
-      CURLOPT_POSTFIELDS => $post,
-      CURLOPT_HTTPHEADER => array(
-        'Accept: application/json',
-        'Content-Type: application/x-www-form-urlencoded',
-      ),
-    ));
+    $url = Url::fromRoute('history.get_last_node_view')
+      ->setAbsolute();
+    $this->verbose($this->serializer->encode($post, 'json'));
+    return $this->client->post($url->toString(), [
+      'body' => $this->serializer->encode($post, 'json'),
+      'headers' => [
+        'Accept' => 'application/json',
+        'Content-Type' => 'application/x-www-form-urlencoded',
+      ]
+    ]);
   }
 
   /**
@@ -90,24 +100,27 @@ protected function getNodeReadTimestamps(array $node_ids) {
    *   The response body.
    */
   protected function markNodeAsRead($node_id) {
-    return $this->curlExec(array(
-      CURLOPT_URL => \Drupal::url('history.read_node', array('node' => $node_id), array('absolute' => TRUE)),
-      CURLOPT_HTTPHEADER => array(
-        'Accept: application/json',
+    $url = Url::fromRoute('history.read_node', array('node' => $node_id), array('absolute' => TRUE))->toString();
+    return $this->client->post($url, [
+      'headers' => array(
+        'Accept' => 'application/json',
       ),
-    ));
+      'auth' => [$this->user->getUsername(), $this->user->passRaw],
+      'cookies' => $this->curlCookies,
+    ]);
   }
 
   /**
    * Verifies that the history endpoints work.
    */
-  function testHistory() {
+  public function testHistory() {
     $nid = $this->testNode->id();
 
     // Retrieve "last read" timestamp for test node, for the current user.
     $response = $this->getNodeReadTimestamps(array($nid));
-    $this->assertResponse(200);
-    $json = Json::decode($response);
+    $this->assertEqual(200, $response->getStatusCode());
+    $this->verbose($response->getBody());
+    $json = $this->serializer->decode($response->getBody()->getContents(), 'json');
     $this->assertIdentical(array(1 => 0), $json, 'The node has not yet been read.');
 
     // View the node.