diff --git a/core/tests/Drupal/FunctionalJavascriptTests/JavascriptTestBase.php b/core/tests/Drupal/FunctionalJavascriptTests/JavascriptTestBase.php
index 8aa46c7..7e8b85d 100644
--- a/core/tests/Drupal/FunctionalJavascriptTests/JavascriptTestBase.php
+++ b/core/tests/Drupal/FunctionalJavascriptTests/JavascriptTestBase.php
@@ -19,6 +19,13 @@
   protected $minkDefaultDriverClass = PhantomJSDriver::class;
 
   /**
+   * A string used to mark the current page.
+   *
+   * @var string
+   */
+  protected $pageReloadMarker;
+
+  /**
    * {@inheritdoc}
    */
   protected function initMink() {
@@ -139,6 +146,28 @@ protected function createScreenshot($filename, $set_background_color = TRUE) {
   }
 
   /**
+   * Marks the page to assist determining if the page has been reloaded.
+   */
+  protected function markCurrentPage() {
+    $this->pageReloadMarker = $this->randomMachineName();
+    $this->getSession()->executeScript('document.body.appendChild(document.createTextNode("' . $this->pageReloadMarker . '"));');
+  }
+
+  /**
+   * Asserts that the page has not been reloaded.
+   */
+  protected function assertPageNotReloaded() {
+    $this->assertSession()->pageTextContains($this->pageReloadMarker);
+  }
+
+  /**
+   * Asserts that the page has been reloaded.
+   */
+  protected function assertPageReloaded() {
+    $this->assertSession()->pageTextNotContains($this->pageReloadMarker);
+  }
+
+  /**
    * {@inheritdoc}
    */
   public function assertSession($name = NULL) {