diff --git a/core/modules/tour/src/Tests/TourTestBase.php b/core/modules/tour/src/Tests/TourTestBase.php
deleted file mode 100644
index 46b7821ec58..00000000000
--- a/core/modules/tour/src/Tests/TourTestBase.php
+++ /dev/null
@@ -1,76 +0,0 @@
-<?php
-
-namespace Drupal\tour\Tests;
-
-use Drupal\Component\Render\FormattableMarkup;
-use Drupal\simpletest\WebTestBase;
-
-@trigger_error('\Drupal\tour\Tests\TourTestBase is deprecated in 8.4.0 and will be removed before Drupal 9.0.0. Instead, use \Drupal\Tests\tour\Functional\TourTestBase.', E_USER_DEPRECATED);
-
-/**
- * Base class for testing Tour functionality.
- *
- * @deprecated in drupal:8.4.0 and is removed from drupal:9.0.0.
- *   Use \Drupal\Tests\tour\Functional\TourTestBase instead.
- */
-abstract class TourTestBase extends WebTestBase {
-
-  /**
-   * Assert function to determine if tips rendered to the page
-   * have a corresponding page element.
-   *
-   * @code
-   * // Basic example.
-   * $this->assertTourTips();
-   *
-   * // Advanced example. The following would be used for multipage or
-   * // targeting a specific subset of tips.
-   * $tips = array();
-   * $tips[] = array('data-id' => 'foo');
-   * $tips[] = array('data-id' => 'bar');
-   * $tips[] = array('data-class' => 'baz');
-   * $this->assertTourTips($tips);
-   * @endcode
-   *
-   * @param array $tips
-   *   A list of tips which provide either a "data-id" or "data-class".
-   */
-  public function assertTourTips($tips = []) {
-    // Get the rendered tips and their data-id and data-class attributes.
-    if (empty($tips)) {
-      // Tips are rendered as <li> elements inside <ol id="tour">.
-      $rendered_tips = $this->xpath('//ol[@id = "tour"]//li[starts-with(@class, "tip")]');
-      foreach ($rendered_tips as $rendered_tip) {
-        $attributes = (array) $rendered_tip->attributes();
-        $tips[] = $attributes['@attributes'];
-      }
-    }
-
-    // If the tips are still empty we need to fail.
-    if (empty($tips)) {
-      $this->fail('Could not find tour tips on the current page.');
-    }
-    else {
-      // Check for corresponding page elements.
-      $total = 0;
-      $modals = 0;
-      foreach ($tips as $tip) {
-        if (!empty($tip['data-id'])) {
-          $elements = $this->xpath('//*[@id="' . $tip['data-id'] . '"]');
-          $this->assertTrue(!empty($elements) && count($elements) === 1, new FormattableMarkup('Found corresponding page element for tour tip with id #%data-id', ['%data-id' => $tip['data-id']]));
-        }
-        elseif (!empty($tip['data-class'])) {
-          $elements = $this->xpath('//*[contain(@class, "' . $tip['data-id'] . '")]');
-          $this->assertFalse(empty($elements), new FormattableMarkup('Found corresponding page element for tour tip with class .%data-class', ['%data-class' => $tip['data-class']]));
-        }
-        else {
-          // It's a modal.
-          $modals++;
-        }
-        $total++;
-      }
-      $this->pass(new FormattableMarkup('Total %total Tips tested of which %modals modal(s).', ['%total' => $total, '%modals' => $modals]));
-    }
-  }
-
-}