diff --git a/core/tests/Drupal/FunctionalTests/Installer/StandardInstallerTest.php b/core/tests/Drupal/FunctionalTests/Installer/StandardInstallerTest.php
index 5f9ac65f8431ceb669451bb4a3a21681ddc62d31..e587f1003a60ecad53ba120e97d7f3b9164391f6 100644
--- a/core/tests/Drupal/FunctionalTests/Installer/StandardInstallerTest.php
+++ b/core/tests/Drupal/FunctionalTests/Installer/StandardInstallerTest.php
@@ -37,19 +37,6 @@ protected function setUpSite() {
     parent::setUpSite();
   }
 
-  /**
-   * {@inheritdoc}
-   */
-  protected function curlExec($curl_options, $redirect = FALSE) {
-    // Ensure that we see the classy progress CSS on the batch page.
-    // Batch processing happens as part of HTTP redirects, so we can access the
-    // HTML of the batch page.
-    if (strpos($curl_options[CURLOPT_URL], '&id=1&op=do_nojs') !== FALSE) {
-      $this->assertRaw('themes/classy/css/components/progress.css');
-    }
-    return parent::curlExec($curl_options, $redirect);
-  }
-
   /**
    * Ensures that the exported standard configuration is up to date.
    */