SystemConfigFormTest.php

<?php

namespace Drupal\Tests\system\Functional\Form;

use Drupal\Tests\BrowserTestBase;

/**
 * Tests the SystemConfigFormTestBase class.
 *
 * @group Form
 */
class SystemConfigFormTest extends BrowserTestBase {
    
    /**
     * Modules to enable.
     *
     * @var array
     */
    public static $modules = [
        'form_test',
    ];
    
    /**
     * {@inheritdoc}
     */
    protected $defaultTheme = 'stark';
    
    /**
     * Tests the SystemConfigFormTestBase class.
     */
    public function testSystemConfigForm() {
        $this->drupalGet('form-test/system-config-form');
        $element = $this->xpath('//div[@id = :id]/input[contains(@class, :class)]', [
            ':id' => 'edit-actions',
            ':class' => 'button--primary',
        ]);
        $this->assertNotEmpty($element, 'The primary action submit button was found.');
        $this->drupalPostForm(NULL, [], t('Save configuration'));
        $this->assertText(t('The configuration options have been saved.'));
    }

}