diff --git a/core/lib/Drupal/Core/Form/FormBuilder.php b/core/lib/Drupal/Core/Form/FormBuilder.php
index 5a2bed5..37c913a 100644
--- a/core/lib/Drupal/Core/Form/FormBuilder.php
+++ b/core/lib/Drupal/Core/Form/FormBuilder.php
@@ -620,7 +620,7 @@ public function processForm($form_id, &$form, &$form_state) {
         // possibly ending execution. We make sure we do not react to the batch
         // that is already being processed (if a batch operation performs a
         // self::submitForm).
-        if ($batch =& batch_get() && !isset($batch['current_set'])) {
+        if ($batch = &$this->batchGet() && !isset($batch['current_set'])) {
           // Store $form_state information in the batch definition.
           // We need the full $form_state when either:
           // - Some submit handlers were saved to be called during batch
@@ -1195,7 +1195,7 @@ public function executeHandlers($type, &$form, &$form_state) {
       // Check if a previous _submit handler has set a batch, but make sure we
       // do not react to a batch that is already being processed (for instance
       // if a batch operation performs a self::submitForm()).
-      if ($type == 'submit' && ($batch =& batch_get()) && !isset($batch['id'])) {
+      if ($type == 'submit' && ($batch = &$this->batchGet()) && !isset($batch['id'])) {
         // Some previous submit handler has set a batch. To ensure correct
         // execution order, store the call in a special 'control' batch set.
         // See _batch_next_set().
@@ -1837,4 +1837,11 @@ public function setRequest(Request $request) {
     $this->request = $request;
   }
 
+  /**
+   * Wraps batch_get().
+   */
+  protected function &batchGet() {
+    return batch_get();
+  }
+
 }
diff --git a/core/tests/Drupal/Tests/Core/Form/FormTestBase.php b/core/tests/Drupal/Tests/Core/Form/FormTestBase.php
index 2ff4858..3b7a97f 100644
--- a/core/tests/Drupal/Tests/Core/Form/FormTestBase.php
+++ b/core/tests/Drupal/Tests/Core/Form/FormTestBase.php
@@ -16,6 +16,8 @@
 
 /**
  * Provides a base class for testing form functionality.
+ *
+ * @see \Drupal\Core\Form\FormBuilder
  */
 abstract class FormTestBase extends UnitTestCase {
 
@@ -321,11 +323,20 @@ public function drupalStaticReset($name = NULL) {
     static::$seenIds = array();
   }
 
+  /**
+   * {@inheritdoc}
+   */
+  protected function &batchGet() {
+    $batch = array();
+    return $batch;
+  }
+
 }
 
 }
 
 namespace {
+
   function test_form_id() {
     $form['test'] = array(
       '#type' => 'textfield',
@@ -351,10 +362,5 @@ function test_form_id() {
     );
     return $form;
   }
-  if (!function_exists('batch_get')) {
-    function &batch_get() {
-      $batch = array();
-      return $batch;
-    }
-  }
+
 }