+<?php
+
+namespace Drupal\Tests\system\Kernel\Form;
+
+use Drupal\Core\Form\FormInterface;
+use Drupal\Core\Form\FormState;
+use Drupal\Core\Form\FormStateInterface;
+use Drupal\KernelTests\KernelTestBase;
+use Symfony\Component\CssSelector\CssSelectorConverter;
+
+/**
+ * Tests the maxlength HTML attribute on form elements.
+ *
+ * @group Form
+ */
+class FormElementMaxlengthTest extends KernelTestBase implements FormInterface {
+
+ /**
+ * {@inheritdoc}
+ */
+ public static $modules = ['system'];
+
+ /**
+ * {@inheritdoc}
+ */
+ public function getFormId() {
+ return 'form_test_maxlength';
+ }
+
+ /**
+ * {@inheritdoc}
+ */
+ public function buildForm(array $form, FormStateInterface $form_state) {
+ $form['title'] = [
+ '#type' => 'textfield',
+ '#maxlength' => 255,
+ ];
+
+ $form['description'] = [
+ '#type' => 'textarea',
+ '#maxlength' => 255,
+ ];
+
+ $form['submit'] = [
+ '#type' => 'submit',
+ '#value' => 'Submit',
+ ];
+
+ return $form;
+ }
+
+ /**
+ * {@inheritdoc}
+ */
+ public function submitForm(array &$form, FormStateInterface $form_state) {}
+
+ /**
+ * {@inheritdoc}
+ */
+ public function validateForm(array &$form, FormStateInterface $form_state) {}
+
+ /**
+ * Ensures maxlength attribute can be used in compatible elements.
+ */
+ public function testAttributes() {
+
+ /** @var \Drupal\Core\Form\FormBuilderInterface $form_builder */
+ $form_builder = $this->container->get('form_builder');
+ $form_state = new FormState();
+ $elements = $form_builder->buildForm($this, $form_state);
+ $this->render($elements);
+
+ $css_selector_converter = new CssSelectorConverter();
+ $elements = $this->xpath($css_selector_converter->toXPath('input[name=title][maxlength=255]'));
+ $this->assertCount(1, $elements, 'Text field has correct maxlength in form.');
+ $elements = $this->xpath($css_selector_converter->toXPath('textarea[name=description][maxlength=255]'));
+ $this->assertCount(1, $elements, 'Textarea field has correct maxlength in form.');
+ }
+
+}