SystemConfigFormTest.php

<?php

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

use Drupal\Tests\BrowserTestBase;

/**
 * Tests the SystemConfigFormTestBase class.
 *
 * @group Form
 */
class SystemConfigFormTest extends BrowserTestBase {
  
  /**
   * {@inheritdoc}
   */
  protected static $modules = [
    'form_test',
  ];
  
  /**
   * {@inheritdoc}
   */
  protected $defaultTheme = 'stark';
  
  /**
   * Tests the SystemConfigFormTestBase class.
   */
  public function testSystemConfigForm() : void {
    $this->drupalGet('form-test/system-config-form');
    // Verify the primary action submit button is found.
    $this->assertSession()
      ->elementExists('xpath', "//div[@id = 'edit-actions']/input[contains(@class, 'button--primary')]");
    $this->submitForm([], 'Save configuration');
    $this->assertSession()
      ->pageTextContains('The configuration options have been saved.');
  }

}