--- /dev/null
+<?php
+
+namespace Drupal\field_test\Plugin\Field\FieldType;
+
+/**
+ * Defines the 'hidden_test' entity field item.
+ *
+ * @FieldType(
+ * id = "hidden_test_field",
+ * label = @Translation("Hidden from UI test field"),
+ * description = @Translation("Dummy hidden field type used for tests."),
+ * no_ui = TRUE,
+ * default_widget = "test_field_widget",
+ * default_formatter = "field_test_default"
+ * )
+ */
+class HiddenTestItem extends TestItem {
+
+}