DefaultMetatagsTest.php

<?php

namespace Drupal\Tests\system\Functional\Page;

use Drupal\Tests\BrowserTestBase;

/**
 * Tests default HTML metatags on a page.
 *
 * @group Page
 */
class DefaultMetatagsTest extends BrowserTestBase {
    
    /**
     * {@inheritdoc}
     */
    protected $defaultTheme = 'stark';
    
    /**
     * Tests meta tags.
     */
    public function testMetaTag() {
        $this->drupalGet('');
        // Ensures that the charset metatag is on the page.
        $this->assertSession()
            ->elementsCount('xpath', '//meta[@charset="utf-8"]', 1);
        // Ensure that the charset one is the first metatag.
        $result = $this->xpath('//meta');
        $this->assertEquals('utf-8', (string) $result[0]->getAttribute('charset'));
        // Ensure that the icon is on the page.
        $this->assertSession()
            ->elementsCount('xpath', '//link[@rel = "icon"]', 1);
    }

}