SimplestTest.php

<?php

namespace Drupal\Tests\ajax_example\FunctionalJavascript;

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

/**
 * Test the user interactions for the Simplest example.
 *
 * @group ajax_example
 */
class SimplestTest extends WebDriverTestBase {
    
    /**
     * {@inheritdoc}
     */
    protected $defaultTheme = 'stark';
    
    /**
     * {@inheritdoc}
     */
    protected static $modules = [
        'ajax_example',
    ];
    
    /**
     * Test AJAX behavior for the dropdown selector.
     *
     * We'll perform the following steps:
     * - Open the simplest example page.
     * - Verify that our AJAX wrapper element is present, but is empty.
     * - Cause events by changing the value of the dropdown for all the different
     *   values.
     * - Verify that the prompt text changes when the dropdown changes.
     */
    public function testAutotextfields() {
        // Get the page.
        $this->drupalGet(Url::fromRoute('ajax_example.simplest'));
        // Get our Mink stuff.
        $page = $this->getSession()
            ->getPage();
        $assert = $this->assertSession();
        // Don't repeat ourselves. This makes it easier if we change the markup
        // later.
        $description_selector = '#replace-textfield-container div.description';
        // Check our initial state.
        $assert->elementExists('css', '#replace-textfield-container');
        $assert->elementNotExists('css', $description_selector);
        // Cause events by changing the value of the dropdown for all the different
        // values. Start with three so the change event is triggered.
        foreach ([
            'three',
            'two',
            'one',
        ] as $value) {
            // Select the dropdown value.
            $page->selectFieldOption('changethis', $value);
            // Wait for AJAX to happen.
            $assert->assertWaitOnAjaxRequest();
            // Assert that the description exists.
            $assert->elementExists('css', $description_selector);
            // Get the description element from the page.
            $prompt_element = $page->find('css', $description_selector);
            // Verify that the prompt text changes when the dropdown changes.
            $this->assertEquals("Say why you chose '{$value}'", $prompt_element->getText());
        }
    }

}