FormStoragePageCacheTest.php

<?php

declare (strict_types=1);
namespace Drupal\Tests\system\Functional\Form;

use Drupal\Tests\BrowserTestBase;

/**
 * Tests form storage from cached pages.
 *
 * @group Form
 */
class FormStoragePageCacheTest extends BrowserTestBase {
    
    /**
     * @var array
     */
    protected static $modules = [
        'form_test',
    ];
    
    /**
     * {@inheritdoc}
     */
    protected $defaultTheme = 'stark';
    
    /**
     * {@inheritdoc}
     */
    protected function setUp() : void {
        parent::setUp();
        $config = $this->config('system.performance');
        $config->set('cache.page.max_age', 300);
        $config->save();
    }
    
    /**
     * Return the build id of the current form.
     */
    protected function getFormBuildId() {
        // Ensure the hidden 'form_build_id' field is unique.
        $this->assertSession()
            ->elementsCount('xpath', '//input[@name="form_build_id"]', 1);
        return (string) $this->assertSession()
            ->hiddenFieldExists('form_build_id')
            ->getAttribute('value');
    }
    
    /**
     * Build-id is regenerated when validating cached form.
     */
    public function testValidateFormStorageOnCachedPage() : void {
        $this->drupalGet('form-test/form-storage-page-cache');
        $this->assertSession()
            ->responseHeaderEquals('X-Drupal-Cache', 'MISS');
        $this->assertSession()
            ->pageTextContains('No old build id');
        $build_id_initial = $this->getFormBuildId();
        // Trigger validation error by submitting an empty title.
        $edit = [
            'title' => '',
        ];
        $this->submitForm($edit, 'Save');
        $this->assertSession()
            ->pageTextContains('No old build id');
        $build_id_first_validation = $this->getFormBuildId();
        $this->assertNotEquals($build_id_initial, $build_id_first_validation, 'Build id changes when form validation fails');
        // Trigger validation error by again submitting an empty title.
        $edit = [
            'title' => '',
        ];
        $this->submitForm($edit, 'Save');
        $this->assertSession()
            ->pageTextContains('No old build id');
        $build_id_second_validation = $this->getFormBuildId();
        $this->assertEquals($build_id_first_validation, $build_id_second_validation, 'Build id remains the same when form validation fails subsequently');
        // Repeat the test sequence but this time with a page loaded from the cache.
        $this->drupalGet('form-test/form-storage-page-cache');
        $this->assertSession()
            ->responseHeaderEquals('X-Drupal-Cache', 'HIT');
        $this->assertSession()
            ->pageTextContains('No old build id');
        $build_id_from_cache_initial = $this->getFormBuildId();
        $this->assertEquals($build_id_initial, $build_id_from_cache_initial, 'Build id is the same as on the first request');
        // Trigger validation error by submitting an empty title.
        $edit = [
            'title' => '',
        ];
        $this->submitForm($edit, 'Save');
        $this->assertSession()
            ->pageTextContains('No old build id');
        $build_id_from_cache_first_validation = $this->getFormBuildId();
        $this->assertNotEquals($build_id_initial, $build_id_from_cache_first_validation, 'Build id changes when form validation fails');
        $this->assertNotEquals($build_id_first_validation, $build_id_from_cache_first_validation, 'Build id from first user is not reused');
        // Trigger validation error by again submitting an empty title.
        $edit = [
            'title' => '',
        ];
        $this->submitForm($edit, 'Save');
        $this->assertSession()
            ->pageTextContains('No old build id');
        $build_id_from_cache_second_validation = $this->getFormBuildId();
        $this->assertEquals($build_id_from_cache_first_validation, $build_id_from_cache_second_validation, 'Build id remains the same when form validation fails subsequently');
    }
    
    /**
     * Build-id is regenerated when rebuilding cached form.
     */
    public function testRebuildFormStorageOnCachedPage() : void {
        $this->drupalGet('form-test/form-storage-page-cache');
        $this->assertSession()
            ->responseHeaderEquals('X-Drupal-Cache', 'MISS');
        $this->assertSession()
            ->pageTextContains('No old build id');
        $build_id_initial = $this->getFormBuildId();
        // Trigger rebuild, should regenerate build id. When a submit handler
        // triggers a rebuild, the form is built twice in the same POST request,
        // and during the second build, there is an old build ID, but because the
        // form is not cached during the initial GET request, it is different from
        // that initial build ID.
        $edit = [
            'title' => 'something',
        ];
        $this->submitForm($edit, 'Rebuild');
        $this->assertSession()
            ->pageTextNotContains('No old build id');
        $this->assertSession()
            ->pageTextNotContains($build_id_initial);
        $build_id_first_rebuild = $this->getFormBuildId();
        $this->assertNotEquals($build_id_initial, $build_id_first_rebuild, 'Build id changes on first rebuild.');
        // Trigger subsequent rebuild, should regenerate the build id again.
        $edit = [
            'title' => 'something',
        ];
        $this->submitForm($edit, 'Rebuild');
        $this->assertSession()
            ->pageTextContains($build_id_first_rebuild);
        $build_id_second_rebuild = $this->getFormBuildId();
        $this->assertNotEquals($build_id_first_rebuild, $build_id_second_rebuild, 'Build id changes on second rebuild.');
    }

}