FormTest.php

<?php

namespace Drupal\Tests\system\Functional\Form;

use Drupal\Component\Serialization\Json;
use Drupal\Component\Utility\Html;
use Drupal\Component\Render\FormattableMarkup;
use Drupal\Core\Form\FormState;
use Drupal\Core\Render\Element;
use Drupal\Core\Url;
use Drupal\form_test\Form\FormTestDisabledElementsForm;
use Drupal\Tests\BrowserTestBase;
use Drupal\user\RoleInterface;
use Drupal\filter\Entity\FilterFormat;
use Behat\Mink\Element\NodeElement;

/**
 * Tests various form element validation mechanisms.
 *
 * @group Form
 */
class FormTest extends BrowserTestBase {
    
    /**
     * Modules to enable.
     *
     * @var array
     */
    public static $modules = [
        'filter',
        'form_test',
        'file',
        'datetime',
    ];
    
    /**
     * {@inheritdoc}
     */
    protected $defaultTheme = 'classy';
    protected function setUp() {
        parent::setUp();
        $filtered_html_format = FilterFormat::create([
            'format' => 'filtered_html',
            'name' => 'Filtered HTML',
        ]);
        $filtered_html_format->save();
        $filtered_html_permission = $filtered_html_format->getPermissionName();
        user_role_grant_permissions(RoleInterface::ANONYMOUS_ID, [
            $filtered_html_permission,
        ]);
    }
    
    /**
     * Check several empty values for required forms elements.
     *
     * Carriage returns, tabs, spaces, and unchecked checkbox elements are not
     * valid content for a required field.
     *
     * If the form field is found in $form_state->getErrors() then the test pass.
     */
    public function testRequiredFields() {
        // Originates from https://www.drupal.org/node/117748.
        // Sets of empty strings and arrays.
        $empty_strings = [
            '""' => "",
            '"\\n"' => "\n",
            '" "' => " ",
            '"\\t"' => "\t",
            '" \\n\\t "' => " \n\t ",
            '"\\n\\n\\n\\n\\n"' => "\n\n\n\n\n",
        ];
        $empty_arrays = [
            'array()' => [],
        ];
        $empty_checkbox = [
            NULL,
        ];
        $elements['textfield']['element'] = [
            '#title' => $this->randomMachineName(),
            '#type' => 'textfield',
        ];
        $elements['textfield']['empty_values'] = $empty_strings;
        $elements['telephone']['element'] = [
            '#title' => $this->randomMachineName(),
            '#type' => 'tel',
        ];
        $elements['telephone']['empty_values'] = $empty_strings;
        $elements['url']['element'] = [
            '#title' => $this->randomMachineName(),
            '#type' => 'url',
        ];
        $elements['url']['empty_values'] = $empty_strings;
        $elements['search']['element'] = [
            '#title' => $this->randomMachineName(),
            '#type' => 'search',
        ];
        $elements['search']['empty_values'] = $empty_strings;
        $elements['password']['element'] = [
            '#title' => $this->randomMachineName(),
            '#type' => 'password',
        ];
        $elements['password']['empty_values'] = $empty_strings;
        $elements['password_confirm']['element'] = [
            '#title' => $this->randomMachineName(),
            '#type' => 'password_confirm',
        ];
        // Provide empty values for both password fields.
        foreach ($empty_strings as $key => $value) {
            $elements['password_confirm']['empty_values'][$key] = [
                'pass1' => $value,
                'pass2' => $value,
            ];
        }
        $elements['textarea']['element'] = [
            '#title' => $this->randomMachineName(),
            '#type' => 'textarea',
        ];
        $elements['textarea']['empty_values'] = $empty_strings;
        $elements['radios']['element'] = [
            '#title' => $this->randomMachineName(),
            '#type' => 'radios',
            '#options' => [
                '' => t('None'),
                $this->randomMachineName(),
                $this->randomMachineName(),
                $this->randomMachineName(),
            ],
        ];
        $elements['radios']['empty_values'] = $empty_arrays;
        $elements['checkbox']['element'] = [
            '#title' => $this->randomMachineName(),
            '#type' => 'checkbox',
            '#required' => TRUE,
        ];
        $elements['checkbox']['empty_values'] = $empty_checkbox;
        $elements['checkboxes']['element'] = [
            '#title' => $this->randomMachineName(),
            '#type' => 'checkboxes',
            '#options' => [
                $this->randomMachineName(),
                $this->randomMachineName(),
                $this->randomMachineName(),
            ],
        ];
        $elements['checkboxes']['empty_values'] = $empty_arrays;
        $elements['select']['element'] = [
            '#title' => $this->randomMachineName(),
            '#type' => 'select',
            '#options' => [
                '' => t('None'),
                $this->randomMachineName(),
                $this->randomMachineName(),
                $this->randomMachineName(),
            ],
        ];
        $elements['select']['empty_values'] = $empty_strings;
        $elements['file']['element'] = [
            '#title' => $this->randomMachineName(),
            '#type' => 'file',
        ];
        $elements['file']['empty_values'] = $empty_strings;
        // Regular expression to find the expected marker on required elements.
        $required_marker_preg = '@<.*?class=".*?js-form-required.*form-required.*?">@';
        // Go through all the elements and all the empty values for them.
        foreach ($elements as $type => $data) {
            foreach ($data['empty_values'] as $key => $empty) {
                foreach ([
                    TRUE,
                    FALSE,
                ] as $required) {
                    $form_id = $this->randomMachineName();
                    $form = [];
                    $form_state = new FormState();
                    $form['op'] = [
                        '#type' => 'submit',
                        '#value' => t('Submit'),
                    ];
                    $element = $data['element']['#title'];
                    $form[$element] = $data['element'];
                    $form[$element]['#required'] = $required;
                    $user_input[$element] = $empty;
                    $user_input['form_id'] = $form_id;
                    $form_state->setUserInput($user_input);
                    $form_state->setFormObject(new StubForm($form_id, $form));
                    $form_state->setMethod('POST');
                    // The form token CSRF protection should not interfere with this test,
                    // so we bypass it by setting the token to FALSE.
                    $form['#token'] = FALSE;
                    \Drupal::formBuilder()->prepareForm($form_id, $form, $form_state);
                    \Drupal::formBuilder()->processForm($form_id, $form, $form_state);
                    $errors = $form_state->getErrors();
                    // Form elements of type 'radios' throw all sorts of PHP notices
                    // when you try to render them like this, so we ignore those for
                    // testing the required marker.
                    // @todo Fix this work-around (https://www.drupal.org/node/588438).
                    $form_output = $type == 'radios' ? '' : \Drupal::service('renderer')->renderRoot($form);
                    if ($required) {
                        // Make sure we have a form error for this element.
                        $this->assertTrue(isset($errors[$element]), "Check empty({$key}) '{$type}' field '{$element}'");
                        if (!empty($form_output)) {
                            // Make sure the form element is marked as required.
                            $this->assertRegExp($required_marker_preg, (string) $form_output, "Required '{$type}' field is marked as required");
                        }
                    }
                    else {
                        if (!empty($form_output)) {
                            // Make sure the form element is *not* marked as required.
                            $this->assertNotRegExp($required_marker_preg, (string) $form_output, "Optional '{$type}' field is not marked as required");
                        }
                        if ($type == 'select') {
                            // Select elements are going to have validation errors with empty
                            // input, since those are illegal choices. Just make sure the
                            // error is not "field is required".
                            $this->assertTrue(empty($errors[$element]) || strpos('field is required', (string) $errors[$element]) === FALSE, "Optional '{$type}' field '{$element}' is not treated as a required element");
                        }
                        else {
                            // Make sure there is *no* form error for this element. We're
                            // not using assertEmpty() because the array key might not exist.
                            $this->assertTrue(empty($errors[$element]), "Optional '{$type}' field '{$element}' has no errors with empty input");
                        }
                    }
                }
            }
        }
        // Clear the expected form error messages so they don't appear as exceptions.
        \Drupal::messenger()->deleteAll();
    }
    
    /**
     * Tests validation for required checkbox, select, and radio elements.
     *
     * Submits a test form containing several types of form elements. The form
     * is submitted twice, first without values for required fields and then
     * with values. Each submission is checked for relevant error messages.
     *
     * @see \Drupal\form_test\Form\FormTestValidateRequiredForm
     */
    public function testRequiredCheckboxesRadio() {
        $form = \Drupal::formBuilder()->getForm('\\Drupal\\form_test\\Form\\FormTestValidateRequiredForm');
        // Attempt to submit the form with no required fields set.
        $edit = [];
        $this->drupalPostForm('form-test/validate-required', $edit, 'Submit');
        // The only error messages that should appear are the relevant 'required'
        // messages for each field.
        $expected = [];
        foreach ([
            'textfield',
            'checkboxes',
            'select',
            'radios',
        ] as $key) {
            if (isset($form[$key]['#required_error'])) {
                $expected[] = $form[$key]['#required_error'];
            }
            elseif (isset($form[$key]['#form_test_required_error'])) {
                $expected[] = $form[$key]['#form_test_required_error'];
            }
            else {
                $expected[] = t('@name field is required.', [
                    '@name' => $form[$key]['#title'],
                ]);
            }
        }
        // Check the page for error messages.
        $errors = $this->xpath('//div[contains(@class, "error")]//li');
        foreach ($errors as $error) {
            $expected_key = array_search($error->getText(), $expected);
            // If the error message is not one of the expected messages, fail.
            if ($expected_key === FALSE) {
                $this->fail(new FormattableMarkup("Unexpected error message: @error", [
                    '@error' => $error[0],
                ]));
            }
            else {
                unset($expected[$expected_key]);
            }
        }
        // Fail if any expected messages were not found.
        foreach ($expected as $not_found) {
            $this->fail(new FormattableMarkup("Found error message: @error", [
                '@error' => $not_found,
            ]));
        }
        // Verify that input elements are still empty.
        $this->assertFieldByName('textfield', '');
        $this->assertNoFieldChecked('edit-checkboxes-foo');
        $this->assertNoFieldChecked('edit-checkboxes-bar');
        $this->assertOptionSelected('edit-select', '');
        $this->assertNoFieldChecked('edit-radios-foo');
        $this->assertNoFieldChecked('edit-radios-bar');
        $this->assertNoFieldChecked('edit-radios-optional-foo');
        $this->assertNoFieldChecked('edit-radios-optional-bar');
        $this->assertNoFieldChecked('edit-radios-optional-default-value-false-foo');
        $this->assertNoFieldChecked('edit-radios-optional-default-value-false-bar');
        // Submit again with required fields set and verify that there are no
        // error messages.
        $edit = [
            'textfield' => $this->randomString(),
            'checkboxes[foo]' => TRUE,
            'select' => 'foo',
            'radios' => 'bar',
        ];
        $this->drupalPostForm(NULL, $edit, 'Submit');
        $this->assertNoFieldByXpath('//div[contains(@class, "error")]', FALSE, 'No error message is displayed when all required fields are filled.');
        $this->assertRaw("The form_test_validate_required_form form was submitted successfully.", 'Validation form submitted successfully.');
    }
    
    /**
     * Tests that input is retained for safe elements even with an invalid token.
     *
     * Submits a test form containing several types of form elements.
     */
    public function testInputWithInvalidToken() {
        // We need to be logged in to have CSRF tokens.
        $account = $this->createUser();
        $this->drupalLogin($account);
        // Submit again with required fields set but an invalid form token and
        // verify that all the values are retained.
        $this->drupalGet(Url::fromRoute('form_test.validate_required'));
        $this->assertSession()
            ->elementExists('css', 'input[name="form_token"]')
            ->setValue('invalid token');
        $random_string = $this->randomString();
        $edit = [
            'textfield' => $random_string,
            'checkboxes[bar]' => TRUE,
            'select' => 'bar',
            'radios' => 'foo',
        ];
        $this->drupalPostForm(NULL, $edit, 'Submit');
        $this->assertFieldByXpath('//div[contains(@class, "error")]', NULL, 'Error message is displayed with invalid token even when required fields are filled.');
        $assert = $this->assertSession();
        $element = $assert->fieldExists('textfield');
        $this->assertEmpty($element->getValue());
        $assert->responseNotContains($random_string);
        $this->assertText('The form has become outdated.');
        // Ensure that we don't use the posted values.
        $this->assertFieldByName('textfield', '');
        $this->assertNoFieldChecked('edit-checkboxes-foo');
        $this->assertNoFieldChecked('edit-checkboxes-bar');
        $this->assertOptionSelected('edit-select', '');
        $this->assertNoFieldChecked('edit-radios-foo');
        // Check another form that has a textarea input.
        $this->drupalGet(Url::fromRoute('form_test.required'));
        $this->assertSession()
            ->elementExists('css', 'input[name="form_token"]')
            ->setValue('invalid token');
        $edit = [
            'textfield' => $this->randomString(),
            'textarea' => $this->randomString() . "\n",
        ];
        $this->drupalPostForm(NULL, $edit, 'Submit');
        $this->assertFieldByXpath('//div[contains(@class, "error")]', NULL, 'Error message is displayed with invalid token even when required fields are filled.');
        $this->assertText('The form has become outdated.');
        $this->assertFieldByName('textfield', '');
        $this->assertFieldByName('textarea', '');
        // Check another form that has a number input.
        $this->drupalGet(Url::fromRoute('form_test.number'));
        $this->assertSession()
            ->elementExists('css', 'input[name="form_token"]')
            ->setValue('invalid token');
        $edit = [
            // We choose a random value which is higher than the default value,
            // so we don't accidentally generate the default value.
'integer_step' => mt_rand(6, 100),
        ];
        $this->drupalPostForm(NULL, $edit, 'Submit');
        $this->assertFieldByXpath('//div[contains(@class, "error")]', NULL, 'Error message is displayed with invalid token even when required fields are filled.');
        $this->assertText('The form has become outdated.');
        $this->assertFieldByName('integer_step', 5);
        // Check a form with a Url field
        $this->drupalGet(Url::fromRoute('form_test.url'));
        $this->assertSession()
            ->elementExists('css', 'input[name="form_token"]')
            ->setValue('invalid token');
        $edit = [
            'url' => $this->randomString(),
        ];
        $this->drupalPostForm(NULL, $edit, 'Submit');
        $this->assertFieldByXpath('//div[contains(@class, "error")]', NULL, 'Error message is displayed with invalid token even when required fields are filled.');
        $this->assertText('The form has become outdated.');
        $this->assertFieldByName('url', '');
    }
    
    /**
     * CSRF tokens for GET forms should not be added by default.
     */
    public function testGetFormsCsrfToken() {
        // We need to be logged in to have CSRF tokens.
        $account = $this->createUser();
        $this->drupalLogin($account);
        $this->drupalGet(Url::fromRoute('form_test.get_form'));
        $this->assertNoRaw('form_token');
    }
    
    /**
     * Tests validation for required textfield element without title.
     *
     * Submits a test form containing a textfield form element without title.
     * The form is submitted twice, first without value for the required field
     * and then with value. Each submission is checked for relevant error
     * messages.
     *
     * @see \Drupal\form_test\Form\FormTestValidateRequiredNoTitleForm
     */
    public function testRequiredTextfieldNoTitle() {
        // Attempt to submit the form with no required field set.
        $edit = [];
        $this->drupalPostForm('form-test/validate-required-no-title', $edit, 'Submit');
        $this->assertNoRaw("The form_test_validate_required_form_no_title form was submitted successfully.", 'Validation form submitted successfully.');
        // Check the page for the error class on the textfield.
        $this->assertFieldByXPath('//input[contains(@class, "error")]', FALSE, 'Error input form element class found.');
        // Check the page for the aria-invalid attribute on the textfield.
        $this->assertFieldByXPath('//input[contains(@aria-invalid, "true")]', FALSE, 'Aria invalid attribute found.');
        // Submit again with required fields set and verify that there are no
        // error messages.
        $edit = [
            'textfield' => $this->randomString(),
        ];
        $this->drupalPostForm(NULL, $edit, 'Submit');
        $this->assertNoFieldByXpath('//input[contains(@class, "error")]', FALSE, 'No error input form element class found.');
        $this->assertRaw("The form_test_validate_required_form_no_title form was submitted successfully.", 'Validation form submitted successfully.');
    }
    
    /**
     * Test default value handling for checkboxes.
     *
     * @see _form_test_checkbox()
     */
    public function testCheckboxProcessing() {
        // First, try to submit without the required checkbox.
        $edit = [];
        $this->drupalPostForm('form-test/checkbox', $edit, t('Submit'));
        $this->assertRaw(t('@name field is required.', [
            '@name' => 'required_checkbox',
        ]), 'A required checkbox is actually mandatory');
        // Now try to submit the form correctly.
        $this->drupalPostForm(NULL, [
            'required_checkbox' => 1,
        ], t('Submit'));
        $values = Json::decode($this->getSession()
            ->getPage()
            ->getContent());
        $expected_values = [
            'disabled_checkbox_on' => 'disabled_checkbox_on',
            'disabled_checkbox_off' => 0,
            'checkbox_on' => 'checkbox_on',
            'checkbox_off' => 0,
            'zero_checkbox_on' => '0',
            'zero_checkbox_off' => 0,
        ];
        foreach ($expected_values as $widget => $expected_value) {
            $this->assertSame($values[$widget], $expected_value, new FormattableMarkup('Checkbox %widget returns expected value (expected: %expected, got: %value)', [
                '%widget' => var_export($widget, TRUE),
                '%expected' => var_export($expected_value, TRUE),
                '%value' => var_export($values[$widget], TRUE),
            ]));
        }
    }
    
    /**
     * Tests validation of #type 'select' elements.
     */
    public function testSelect() {
        $form = \Drupal::formBuilder()->getForm('Drupal\\form_test\\Form\\FormTestSelectForm');
        $this->drupalGet('form-test/select');
        // Verify that the options are escaped as expected.
        $this->assertEscaped('<strong>four</strong>');
        $this->assertNoRaw('<strong>four</strong>');
        // Posting without any values should throw validation errors.
        $this->drupalPostForm(NULL, [], 'Submit');
        $no_errors = [
            'select',
            'select_required',
            'select_optional',
            'empty_value',
            'empty_value_one',
            'no_default_optional',
            'no_default_empty_option_optional',
            'no_default_empty_value_optional',
            'multiple',
            'multiple_no_default',
        ];
        foreach ($no_errors as $key) {
            $this->assertNoText(t('@name field is required.', [
                '@name' => $form[$key]['#title'],
            ]));
        }
        $expected_errors = [
            'no_default',
            'no_default_empty_option',
            'no_default_empty_value',
            'no_default_empty_value_one',
            'multiple_no_default_required',
        ];
        foreach ($expected_errors as $key) {
            $this->assertText(t('@name field is required.', [
                '@name' => $form[$key]['#title'],
            ]));
        }
        // Post values for required fields.
        $edit = [
            'no_default' => 'three',
            'no_default_empty_option' => 'three',
            'no_default_empty_value' => 'three',
            'no_default_empty_value_one' => 'three',
            'multiple_no_default_required[]' => 'three',
        ];
        $this->drupalPostForm(NULL, $edit, 'Submit');
        $values = Json::decode($this->getSession()
            ->getPage()
            ->getContent());
        // Verify expected values.
        $expected = [
            'select' => 'one',
            'empty_value' => 'one',
            'empty_value_one' => 'one',
            'no_default' => 'three',
            'no_default_optional' => 'one',
            'no_default_optional_empty_value' => '',
            'no_default_empty_option' => 'three',
            'no_default_empty_option_optional' => '',
            'no_default_empty_value' => 'three',
            'no_default_empty_value_one' => 'three',
            'no_default_empty_value_optional' => 0,
            'multiple' => [
                'two' => 'two',
            ],
            'multiple_no_default' => [],
            'multiple_no_default_required' => [
                'three' => 'three',
            ],
        ];
        foreach ($expected as $key => $value) {
            $this->assertIdentical($values[$key], $value, new FormattableMarkup('@name: @actual is equal to @expected.', [
                '@name' => $key,
                '@actual' => var_export($values[$key], TRUE),
                '@expected' => var_export($value, TRUE),
            ]));
        }
    }
    
    /**
     * Tests a select element when #options is not set.
     */
    public function testEmptySelect() {
        $this->drupalGet('form-test/empty-select');
        $this->assertFieldByXPath("//select[1]", NULL, 'Select element found.');
        $this->assertNoFieldByXPath("//select[1]/option", NULL, 'No option element found.');
    }
    
    /**
     * Tests sorting and not sorting of options in a select element.
     */
    public function testSelectSorting() {
        $this->drupalGet('form-test/select');
        // Verify the order of the select options.
        $this->validateSelectSorting('unsorted', [
            'uso_first_element',
            'uso_second',
            'uso_zzgroup',
            'uso_gc',
            'uso_ga',
            'uso_gb',
            'uso_yygroup',
            'uso_ge',
            'uso_gd',
            'uso_gf',
            'uso_xxgroup',
            'uso_gz',
            'uso_gi',
            'uso_gh',
            'uso_d',
            'uso_c',
            'uso_b',
            'uso_a',
        ]);
        $this->validateSelectSorting('sorted', [
            'sso_a',
            'sso_d',
            'sso_first_element',
            'sso_b',
            'sso_c',
            'sso_second',
            'sso_xxgroup',
            'sso_gz',
            'sso_gh',
            'sso_gi',
            'sso_yygroup',
            'sso_ge',
            'sso_gd',
            'sso_gf',
            'sso_zzgroup',
            'sso_ga',
            'sso_gb',
            'sso_gc',
        ]);
        $this->validateSelectSorting('sorted_none', [
            'sno_empty',
            'sno_first_element',
            'sno_second',
            'sno_zzgroup',
            'sno_ga',
            'sno_gb',
            'sno_gc',
            'sno_a',
            'sno_d',
            'sno_b',
            'sno_c',
            'sno_xxgroup',
            'sno_gz',
            'sno_gi',
            'sno_gh',
            'sno_yygroup',
            'sno_ge',
            'sno_gd',
            'sno_gf',
        ]);
        $this->validateSelectSorting('sorted_none_nostart', [
            'snn_empty',
            'snn_a',
            'snn_d',
            'snn_first_element',
            'snn_b',
            'snn_c',
            'snn_second',
            'snn_xxgroup',
            'snn_gz',
            'snn_gi',
            'snn_gh',
            'snn_yygroup',
            'snn_ge',
            'snn_gd',
            'snn_gf',
            'snn_zzgroup',
            'snn_ga',
            'snn_gb',
            'snn_gc',
        ]);
        // Verify that #sort_order and #sort_start are not in the page.
        $this->assertSession()
            ->responseNotContains('#sort_order');
        $this->assertSession()
            ->responseNotContains('#sort_start');
    }
    
    /**
     * Validates that the options are in the right order in a select.
     *
     * @param string $select
     *   Name of the select to verify.
     * @param string[] $order
     *   Expected order of its options.
     */
    protected function validateSelectSorting($select, array $order) {
        $option_map_function = function (NodeElement $node) {
            return $node->getTagName() === 'optgroup' ? $node->getAttribute('label') : $node->getValue();
        };
        $option_nodes = $this->getSession()
            ->getPage()
            ->findField($select)
            ->findAll('css', 'option, optgroup');
        $options = array_map($option_map_function, $option_nodes);
        $this->assertIdentical($order, $options);
    }
    
    /**
     * Tests validation of #type 'number' and 'range' elements.
     */
    public function testNumber() {
        $form = \Drupal::formBuilder()->getForm('\\Drupal\\form_test\\Form\\FormTestNumberForm');
        // Array with all the error messages to be checked.
        $error_messages = [
            'no_number' => '%name must be a number.',
            'too_low' => '%name must be higher than or equal to %min.',
            'too_high' => '%name must be lower than or equal to %max.',
            'step_mismatch' => '%name is not a valid number.',
        ];
        // The expected errors.
        $expected = [
            'integer_no_number' => 'no_number',
            'integer_no_step' => 0,
            'integer_no_step_step_error' => 'step_mismatch',
            'integer_step' => 0,
            'integer_step_error' => 'step_mismatch',
            'integer_step_min' => 0,
            'integer_step_min_error' => 'too_low',
            'integer_step_max' => 0,
            'integer_step_max_error' => 'too_high',
            'integer_step_min_border' => 0,
            'integer_step_max_border' => 0,
            'integer_step_based_on_min' => 0,
            'integer_step_based_on_min_error' => 'step_mismatch',
            'float_small_step' => 0,
            'float_step_no_error' => 0,
            'float_step_error' => 'step_mismatch',
            'float_step_hard_no_error' => 0,
            'float_step_hard_error' => 'step_mismatch',
            'float_step_any_no_error' => 0,
        ];
        // First test the number element type, then range.
        foreach ([
            'form-test/number',
            'form-test/number/range',
        ] as $path) {
            // Post form and show errors.
            $this->drupalPostForm($path, [], 'Submit');
            foreach ($expected as $element => $error) {
                // Create placeholder array.
                $placeholders = [
                    '%name' => $form[$element]['#title'],
                    '%min' => isset($form[$element]['#min']) ? $form[$element]['#min'] : '0',
                    '%max' => isset($form[$element]['#max']) ? $form[$element]['#max'] : '0',
                ];
                foreach ($error_messages as $id => $message) {
                    // Check if the error exists on the page, if the current message ID is
                    // expected. Otherwise ensure that the error message is not present.
                    if ($id === $error) {
                        $this->assertRaw(new FormattableMarkup($message, $placeholders));
                    }
                    else {
                        $this->assertNoRaw(new FormattableMarkup($message, $placeholders));
                    }
                }
            }
        }
    }
    
    /**
     * Tests default value handling of #type 'range' elements.
     */
    public function testRange() {
        $this->drupalPostForm('form-test/range', [], 'Submit');
        $values = json_decode($this->getSession()
            ->getPage()
            ->getContent());
        $this->assertEqual($values->with_default_value, 18);
        $this->assertEqual($values->float, 10.5);
        $this->assertEqual($values->integer, 6);
        $this->assertEqual($values->offset, 6.9);
        $this->drupalPostForm('form-test/range/invalid', [], 'Submit');
        $this->assertFieldByXPath('//input[@type="range" and contains(@class, "error")]', NULL, 'Range element has the error class.');
    }
    
    /**
     * Tests validation of #type 'color' elements.
     */
    public function testColorValidation() {
        // Keys are inputs, values are expected results.
        $values = [
            '' => '#000000',
            '#000' => '#000000',
            'AAA' => '#aaaaaa',
            '#af0DEE' => '#af0dee',
            '#99ccBc' => '#99ccbc',
            '#aabbcc' => '#aabbcc',
            '123456' => '#123456',
        ];
        // Tests that valid values are properly normalized.
        foreach ($values as $input => $expected) {
            $edit = [
                'color' => $input,
            ];
            $this->drupalPostForm('form-test/color', $edit, 'Submit');
            $result = json_decode($this->getSession()
                ->getPage()
                ->getContent());
            $this->assertEqual($result->color, $expected);
        }
        // Tests invalid values are rejected.
        $values = [
            '#0008',
            '#1234',
            '#fffffg',
            '#abcdef22',
            '17',
            '#uaa',
        ];
        foreach ($values as $input) {
            $edit = [
                'color' => $input,
            ];
            $this->drupalPostForm('form-test/color', $edit, 'Submit');
            $this->assertRaw(t('%name must be a valid color.', [
                '%name' => 'Color',
            ]));
        }
    }
    
    /**
     * Test handling of disabled elements.
     *
     * @see _form_test_disabled_elements()
     */
    public function testDisabledElements() {
        // Get the raw form in its original state.
        $form_state = new FormState();
        $form = (new FormTestDisabledElementsForm())->buildForm([], $form_state);
        // Build a submission that tries to hijack the form by submitting input for
        // elements that are disabled.
        $edit = [];
        foreach (Element::children($form) as $key) {
            if (isset($form[$key]['#test_hijack_value'])) {
                if (is_array($form[$key]['#test_hijack_value'])) {
                    foreach ($form[$key]['#test_hijack_value'] as $subkey => $value) {
                        $edit[$key . '[' . $subkey . ']'] = $value;
                    }
                }
                else {
                    $edit[$key] = $form[$key]['#test_hijack_value'];
                }
            }
        }
        // Submit the form with no input, as the browser does for disabled elements,
        // and fetch the $form_state->getValues() that is passed to the submit handler.
        $this->drupalPostForm('form-test/disabled-elements', [], t('Submit'));
        $returned_values['normal'] = Json::decode($this->getSession()
            ->getPage()
            ->getContent());
        // Do the same with input, as could happen if JavaScript un-disables an
        // element. drupalPostForm() emulates a browser by not submitting input for
        // disabled elements, so we need to un-disable those elements first.
        $this->drupalGet('form-test/disabled-elements');
        $disabled_elements = [];
        foreach ($this->xpath('//*[@disabled]') as $element) {
            $disabled_elements[] = (string) $element->getAttribute('name');
        }
        // All the elements should be marked as disabled, including the ones below
        // the disabled container.
        $actual_count = count($disabled_elements);
        $expected_count = 42;
        $this->assertEqual($actual_count, $expected_count, new FormattableMarkup('Found @actual elements with disabled property (expected @expected).', [
            '@actual' => count($disabled_elements),
            '@expected' => $expected_count,
        ]));
        // Mink does not "see" hidden elements, so we need to set the value of the
        // hidden element directly.
        $this->assertSession()
            ->elementExists('css', 'input[name="hidden"]')
            ->setValue($edit['hidden']);
        unset($edit['hidden']);
        $this->drupalPostForm(NULL, $edit, t('Submit'));
        $returned_values['hijacked'] = Json::decode($this->getSession()
            ->getPage()
            ->getContent());
        // Ensure that the returned values match the form's default values in both
        // cases.
        foreach ($returned_values as $values) {
            $this->assertFormValuesDefault($values, $form);
        }
    }
    
    /**
     * Assert that the values submitted to a form matches the default values of the elements.
     */
    public function assertFormValuesDefault($values, $form) {
        foreach (Element::children($form) as $key) {
            if (isset($form[$key]['#default_value'])) {
                if (isset($form[$key]['#expected_value'])) {
                    $expected_value = $form[$key]['#expected_value'];
                }
                else {
                    $expected_value = $form[$key]['#default_value'];
                }
                if ($key == 'checkboxes_multiple') {
                    // Checkboxes values are not filtered out.
                    $values[$key] = array_filter($values[$key]);
                }
                $this->assertIdentical($expected_value, $values[$key], new FormattableMarkup('Default value for %type: expected %expected, returned %returned.', [
                    '%type' => $key,
                    '%expected' => var_export($expected_value, TRUE),
                    '%returned' => var_export($values[$key], TRUE),
                ]));
            }
            // Recurse children.
            $this->assertFormValuesDefault($values, $form[$key]);
        }
    }
    
    /**
     * Verify markup for disabled form elements.
     *
     * @see _form_test_disabled_elements()
     */
    public function testDisabledMarkup() {
        $this->drupalGet('form-test/disabled-elements');
        $form = \Drupal::formBuilder()->getForm('\\Drupal\\form_test\\Form\\FormTestDisabledElementsForm');
        $type_map = [
            'textarea' => 'textarea',
            'select' => 'select',
            'weight' => 'select',
            'datetime' => 'datetime',
        ];
        foreach ($form as $name => $item) {
            // Skip special #types.
            if (!isset($item['#type']) || in_array($item['#type'], [
                'hidden',
                'text_format',
            ])) {
                continue;
            }
            // Setup XPath and CSS class depending on #type.
            if (in_array($item['#type'], [
                'button',
                'submit',
            ])) {
                $path = "//!type[contains(@class, :div-class) and @value=:value]";
                $class = 'is-disabled';
            }
            elseif (in_array($item['#type'], [
                'image_button',
            ])) {
                $path = "//!type[contains(@class, :div-class) and @value=:value]";
                $class = 'is-disabled';
            }
            else {
                // starts-with() required for checkboxes.
                $path = "//div[contains(@class, :div-class)]/descendant::!type[starts-with(@name, :name)]";
                $class = 'form-disabled';
            }
            // Replace DOM element name in $path according to #type.
            $type = 'input';
            if (isset($type_map[$item['#type']])) {
                $type = $type_map[$item['#type']];
            }
            if (isset($item['#value']) && is_object($item['#value'])) {
                $item['#value'] = (string) $item['#value'];
            }
            $path = strtr($path, [
                '!type' => $type,
            ]);
            // Verify that the element exists.
            $element = $this->xpath($path, [
                ':name' => Html::escape($name),
                ':div-class' => $class,
                ':value' => isset($item['#value']) ? $item['#value'] : '',
            ]);
            $this->assertTrue(isset($element[0]), new FormattableMarkup('Disabled form element class found for #type %type.', [
                '%type' => $item['#type'],
            ]));
        }
        // Verify special element #type text-format.
        $element = $this->xpath('//div[contains(@class, :div-class)]/descendant::textarea[@name=:name]', [
            ':name' => 'text_format[value]',
            ':div-class' => 'form-disabled',
        ]);
        $this->assertTrue(isset($element[0]), new FormattableMarkup('Disabled form element class found for #type %type.', [
            '%type' => 'text_format[value]',
        ]));
        $element = $this->xpath('//div[contains(@class, :div-class)]/descendant::select[@name=:name]', [
            ':name' => 'text_format[format]',
            ':div-class' => 'form-disabled',
        ]);
        $this->assertTrue(isset($element[0]), new FormattableMarkup('Disabled form element class found for #type %type.', [
            '%type' => 'text_format[format]',
        ]));
    }
    
    /**
     * Test Form API protections against input forgery.
     *
     * @see \Drupal\form_test\Form\FormTestInputForgeryForm
     */
    public function testInputForgery() {
        $this->drupalGet('form-test/input-forgery');
        // The value for checkboxes[two] was changed using post render to simulate
        // an input forgery.
        // @see \Drupal\form_test\Form\FormTestInputForgeryForm::postRender
        $this->drupalPostForm(NULL, [
            'checkboxes[one]' => TRUE,
            'checkboxes[two]' => TRUE,
        ], t('Submit'));
        $this->assertText('An illegal choice has been detected.', 'Input forgery was detected.');
    }
    
    /**
     * Tests required attribute.
     */
    public function testRequiredAttribute() {
        $this->drupalGet('form-test/required-attribute');
        $expected = 'required';
        // Test to make sure the elements have the proper required attribute.
        foreach ([
            'textfield',
            'password',
        ] as $type) {
            $element = $this->xpath('//input[@id=:id and @required=:expected]', [
                ':id' => 'edit-' . $type,
                ':expected' => $expected,
            ]);
            $this->assertTrue(!empty($element), new FormattableMarkup('The @type has the proper required attribute.', [
                '@type' => $type,
            ]));
        }
        // Test to make sure textarea has the proper required attribute.
        $element = $this->xpath('//textarea[@id=:id and @required=:expected]', [
            ':id' => 'edit-textarea',
            ':expected' => $expected,
        ]);
        $this->assertTrue(!empty($element), 'The textarea has the proper required attribute.');
    }

}