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

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

@@ -0,0 +1,64 @@
+<?php
+
+namespace Zumba\Mink\Driver;
+
+use Behat\Mink\Exception\DriverException;
+
+/**
+ * Class WindowTrait
+ * @package Zumba\Mink\Driver
+ */
+trait WindowTrait {
+  /**
+   * Returns the current page window name
+   * @return string
+   */
+  public function getWindowName() {
+    return $this->browser->windowName();
+  }
+
+  /**
+   * Return all the window handles currently present in phantomjs
+   * @return array
+   */
+  public function getWindowNames() {
+    return $this->browser->windowHandles();
+  }
+
+  /**
+   * Switches to window by name if possible
+   * @param $name
+   * @throws DriverException
+   */
+  public function switchToWindow($name = null) {
+    $handles = $this->browser->windowHandles();
+    if ($name === null) {
+      //null means back to the main window
+      return $this->browser->switchToWindow($handles[0]);
+    }
+
+    $windowHandle = $this->browser->windowHandle($name);
+    if (!empty($windowHandle)) {
+      $this->browser->switchToWindow($windowHandle);
+    } else {
+      throw new DriverException("Could not find window handle by a given window name: $name");
+    }
+
+  }
+
+  /**
+   * Resizing a window with specified size
+   * @param int    $width
+   * @param int    $height
+   * @param string $name
+   * @throws DriverException
+   */
+  public function resizeWindow($width, $height, $name = null) {
+    if ($name !== null) {
+      //TODO: add this on the phantomjs stuff
+      throw new DriverException("Resizing other window than the main one is not supported yet");
+    }
+    $this->browser->resize($width, $height);
+  }
+
+}