diff --git a/core/tests/Drupal/Tests/Core/DrupalTest.php b/core/tests/Drupal/Tests/Core/DrupalTest.php
index 8c2e5ad..b37010f 100644
--- a/core/tests/Drupal/Tests/Core/DrupalTest.php
+++ b/core/tests/Drupal/Tests/Core/DrupalTest.php
@@ -332,6 +332,14 @@ public function testTransliteration() {
   }
 
   /**
+   * Tests the formBuilder() method.
+   */
+  public function testFormBuilder() {
+    $this->setMockContainerService('form_builder');
+    $this->assertNotNull(\Drupal::formBuilder());
+  }
+
+  /**
    * Sets up a mock expectation for the container get() method.
    *
    * @param string $service_name