diff --git a/core/modules/filter/src/Tests/FilterCrudTest.php b/core/modules/filter/src/Tests/FilterCrudTest.php
index d2d4d6f..95e1975 100644
--- a/core/modules/filter/src/Tests/FilterCrudTest.php
+++ b/core/modules/filter/src/Tests/FilterCrudTest.php
@@ -7,6 +7,7 @@
 
 namespace Drupal\filter\Tests;
 
+use Drupal\filter\Entity\FilterFormat;
 use Drupal\simpletest\KernelTestBase;
 
 /**
@@ -21,7 +22,7 @@ class FilterCrudTest extends KernelTestBase {
    *
    * @var array
    */
-  public static $modules = array('filter', 'filter_test');
+  public static $modules = ['filter', 'filter_test', 'system', 'user'];
 
   /**
    * Tests CRUD operations for text formats and filters.
@@ -74,6 +75,23 @@ function testTextFormatCrud() {
   }
 
   /**
+   * Tests disabling the fallback text format.
+   */
+  public function testDisableFallbackFormat() {
+    $this->installConfig(['filter']);
+    $message = sprintf("Exception \\LogicalException (message \"The fallback text format 'plain_text' cannot be disabled.\") was thrown.");
+    try {
+      FilterFormat::load('plain_text')->disable();
+      $this->fail($message);
+    }
+    catch (\LogicException $e) {
+      if ($e->getMessage() == "The fallback text format 'plain_text' cannot be disabled.") {
+        $this->pass($message);
+      }
+    }
+  }
+
+  /**
    * Verifies that a text format is properly stored.
    */
   function verifyTextFormat($format) {