diff -u b/core/modules/system/src/Tests/Entity/Update/LangcodeToAsciiUpdateTest.php b/core/modules/system/src/Tests/Entity/Update/LangcodeToAsciiUpdateTest.php
--- b/core/modules/system/src/Tests/Entity/Update/LangcodeToAsciiUpdateTest.php
+++ b/core/modules/system/src/Tests/Entity/Update/LangcodeToAsciiUpdateTest.php
@@ -20,11 +20,10 @@
   /**
    * {@inheritdoc}
    */
-  public function setUp() {
+  public function setDatabaseDumpFiles() {
     $this->databaseDumpFiles = [
       __DIR__ . '/../../../../tests/fixtures/update/drupal-8.bare.standard.php.gz',
     ];
-    parent::setUp();
   }
 
   /**