AdminThemeUpdateTest.php

<?php

namespace Drupal\Tests\system\Functional\Update;

use Drupal\FunctionalTests\Update\UpdatePathTestBase;

/**
 * Tests system.theme:admin is updated.
 *
 * @group system
 * @group legacy
 */
class AdminThemeUpdateTest extends UpdatePathTestBase {
    
    /**
     * {@inheritdoc}
     */
    protected $defaultTheme = 'stark';
    
    /**
     * {@inheritdoc}
     */
    protected function setDatabaseDumpFiles() {
        $this->databaseDumpFiles = [
            __DIR__ . '/../../../../../system/tests/fixtures/update/drupal-8.6.0.bare.testing.php.gz',
            __DIR__ . '/../../../../../system/tests/fixtures/update/drupal-8.admin_theme_0.php',
        ];
    }
    
    /**
     * Tests that system.theme:admin is updated as expected.
     */
    public function testUpdateHookN() {
        $this->assertSame('0', $this->config('system.theme')
            ->get('admin'));
        $this->runUpdates();
        $this->assertSame('', $this->config('system.theme')
            ->get('admin'));
    }

}