Update to Drupal 8.0.0-rc3. For more information, see https://www.drupal.org/node/2608078

vendor/jcalderonzumba/mink-phantomjs-driver/src/CookieTrait.php

@@ -0,0 +1,45 @@
+<?php
+
+namespace Zumba\Mink\Driver;
+
+use Zumba\GastonJS\Cookie;
+
+/**
+ * Trait CookieTrait
+ * @package Zumba\Mink\Driver
+ */
+trait CookieTrait {
+
+  /**
+   * Sets a cookie on the browser, if null value then delete it
+   * @param string $name
+   * @param string $value
+   */
+  public function setCookie($name, $value = null) {
+    if ($value === null) {
+      $this->browser->removeCookie($name);
+    }
+    //TODO: set the cookie with domain, not with url, meaning www.aaa.com or .aaa.com
+    if ($value !== null) {
+      $urlData = parse_url($this->getCurrentUrl());
+      $cookie = array("name" => $name, "value" => $value, "domain" => $urlData["host"]);
+      $this->browser->setCookie($cookie);
+    }
+  }
+
+  /**
+   * Gets a cookie by its name if exists, else it will return null
+   * @param string $name
+   * @return string
+   */
+  public function getCookie($name) {
+    $cookies = $this->browser->cookies();
+    foreach ($cookies as $cookie) {
+      if ($cookie instanceof Cookie && strcmp($cookie->getName(), $name) === 0) {
+        return $cookie->getValue();
+      }
+    }
+    return null;
+  }
+
+}