--- /dev/null
+<?php
+
+namespace Drupal\Tests\system\Functional\Form;
+
+use Drupal\Tests\BrowserTestBase;
+
+/**
+ * Tests form API checkbox handling of various combinations of #default_value
+ * and #return_value.
+ *
+ * @group Form
+ */
+class CheckboxTest extends BrowserTestBase {
+
+ /**
+ * Modules to enable.
+ *
+ * @var array
+ */
+ public static $modules = ['form_test'];
+
+ public function testFormCheckbox() {
+ // Ensure that the checked state is determined and rendered correctly for
+ // tricky combinations of default and return values.
+ foreach ([FALSE, NULL, TRUE, 0, '0', '', 1, '1', 'foobar', '1foobar'] as $default_value) {
+ // Only values that can be used for array indices are supported for
+ // #return_value, with the exception of integer 0, which is not supported.
+ // @see \Drupal\Core\Render\Element\Checkbox::processCheckbox().
+ foreach (['0', '', 1, '1', 'foobar', '1foobar'] as $return_value) {
+ $form_array = \Drupal::formBuilder()->getForm('\Drupal\form_test\Form\FormTestCheckboxTypeJugglingForm', $default_value, $return_value);
+ $form = \Drupal::service('renderer')->renderRoot($form_array);
+ if ($default_value === TRUE) {
+ $checked = TRUE;
+ }
+ elseif ($return_value === '0') {
+ $checked = ($default_value === '0');
+ }
+ elseif ($return_value === '') {
+ $checked = ($default_value === '');
+ }
+ elseif ($return_value === 1 || $return_value === '1') {
+ $checked = ($default_value === 1 || $default_value === '1');
+ }
+ elseif ($return_value === 'foobar') {
+ $checked = ($default_value === 'foobar');
+ }
+ elseif ($return_value === '1foobar') {
+ $checked = ($default_value === '1foobar');
+ }
+ $checked_in_html = strpos($form, 'checked') !== FALSE;
+ $message = format_string('#default_value is %default_value #return_value is %return_value.', ['%default_value' => var_export($default_value, TRUE), '%return_value' => var_export($return_value, TRUE)]);
+ $this->assertIdentical($checked, $checked_in_html, $message);
+ }
+ }
+
+ // Ensure that $form_state->getValues() is populated correctly for a
+ // checkboxes group that includes a 0-indexed array of options.
+ $this->drupalPostForm('form-test/checkboxes-zero/1', [], 'Save');
+ $results = json_decode($this->getSession()->getPage()->getContent());
+ $this->assertIdentical($results->checkbox_off, [0, 0, 0], 'All three in checkbox_off are zeroes: off.');
+ $this->assertIdentical($results->checkbox_zero_default, ['0', 0, 0], 'The first choice is on in checkbox_zero_default');
+ $this->assertIdentical($results->checkbox_string_zero_default, ['0', 0, 0], 'The first choice is on in checkbox_string_zero_default');
+ // Due to Mink driver differences, we cannot submit an empty checkbox value
+ // to drupalPostForm(), even if that empty value is the 'true' value for
+ // the checkbox.
+ $this->drupalGet('form-test/checkboxes-zero/1');
+ $this->assertSession()->fieldExists('checkbox_off[0]')->check();
+ $this->drupalPostForm(NULL, NULL, 'Save');
+ $results = json_decode($this->getSession()->getPage()->getContent());
+ $this->assertIdentical($results->checkbox_off, ['0', 0, 0], 'The first choice is on in checkbox_off but the rest is not');
+
+ // Ensure that each checkbox is rendered correctly for a checkboxes group
+ // that includes a 0-indexed array of options.
+ $this->drupalPostForm('form-test/checkboxes-zero/0', [], 'Save');
+ $checkboxes = $this->xpath('//input[@type="checkbox"]');
+
+ $this->assertIdentical(count($checkboxes), 9, 'Correct number of checkboxes found.');
+ foreach ($checkboxes as $checkbox) {
+ $checked = $checkbox->isChecked();
+ $name = $checkbox->getAttribute('name');
+ $this->assertIdentical($checked, $name == 'checkbox_zero_default[0]' || $name == 'checkbox_string_zero_default[0]', format_string('Checkbox %name correctly checked', ['%name' => $name]));
+ }
+ // Due to Mink driver differences, we cannot submit an empty checkbox value
+ // to drupalPostForm(), even if that empty value is the 'true' value for
+ // the checkbox.
+ $this->drupalGet('form-test/checkboxes-zero/0');
+ $this->assertSession()->fieldExists('checkbox_off[0]')->check();
+ $this->drupalPostForm(NULL, NULL, 'Save');
+ $checkboxes = $this->xpath('//input[@type="checkbox"]');
+
+ $this->assertIdentical(count($checkboxes), 9, 'Correct number of checkboxes found.');
+ foreach ($checkboxes as $checkbox) {
+ $checked = $checkbox->isChecked();
+ $name = (string) $checkbox->getAttribute('name');
+ $this->assertIdentical($checked, $name == 'checkbox_off[0]' || $name == 'checkbox_zero_default[0]' || $name == 'checkbox_string_zero_default[0]', format_string('Checkbox %name correctly checked', ['%name' => $name]));
+ }
+ }
+
+}