SubmitDrivenTest.php

<?php

namespace Drupal\Tests\ajax_example\FunctionalJavascript;

use Drupal\Core\Url;
use Drupal\FunctionalJavascriptTests\WebDriverTestBase;

/**
 * Tests the behavior of the submit-driven AJAX example.
 *
 * @group ajax_example
 */
class SubmitDrivenTest extends WebDriverTestBase {
    
    /**
     * {@inheritdoc}
     */
    protected $defaultTheme = 'stark';
    
    /**
     * {@inheritdoc}
     */
    public static $modules = [
        'ajax_example',
    ];
    
    /**
     * Test the behavior of the submit-driven AJAX example.
     *
     * Behaviors to test:
     * - GET the route ajax_example.submit_driven_ajax.
     * - Examine the DOM to make sure our change hasn't happened yet.
     * - Submit the form.
     * - Wait for the AJAX request to complete.
     * - Examine the DOM to see if our expected change happened.
     */
    public function testSubmitDriven() {
        // Get the session assertion object.
        $assert = $this->assertSession();
        // Get the page.
        $this->drupalGet(Url::fromRoute('ajax_example.submit_driven_ajax'));
        // Examine the DOM to make sure our change hasn't happened yet.
        $assert->pageTextNotContains('Clicked submit (Submit):');
        // Submit the form.
        $this->submitForm([], 'Submit');
        // Wait on the AJAX request.
        $assert->assertWaitOnAjaxRequest();
        // Compare DOM to our expectations.
        $assert->pageTextContains('Clicked submit (Submit):');
    }

}