diff --git a/core/modules/file/lib/Drupal/file/Tests/FileFieldTestBase.php b/core/modules/file/lib/Drupal/file/Tests/FileFieldTestBase.php
index e6c9e68..ed29cba 100644
--- a/core/modules/file/lib/Drupal/file/Tests/FileFieldTestBase.php
+++ b/core/modules/file/lib/Drupal/file/Tests/FileFieldTestBase.php
@@ -71,7 +71,7 @@ function createFileField($name, $type_name, $field_settings = array(), $instance
       'settings' => array(),
       'cardinality' => !empty($field_settings['cardinality']) ? $field_settings['cardinality'] : 1,
     );
-    $field['settings'] = array_merge($field_definition['settings'], $field_settings);
+    $field_definition['settings'] = array_merge($field_definition['settings'], $field_settings);
     $field = entity_create('field_entity', $field_definition);
     $field->save();