NodeViewLanguageTest.php

<?php

namespace Drupal\Tests\node\Functional;

use Drupal\language\Entity\ConfigurableLanguage;

/**
 * Tests the node language extra field display.
 *
 * @group node
 */
class NodeViewLanguageTest extends NodeTestBase {
    
    /**
     * Modules to enable.
     *
     * @var array
     */
    public static $modules = [
        'node',
        'datetime',
        'language',
    ];
    
    /**
     * {@inheritdoc}
     */
    protected $defaultTheme = 'stark';
    
    /**
     * Tests the language extra field display.
     */
    public function testViewLanguage() {
        // Add Spanish language.
        ConfigurableLanguage::createFromLangcode('es')->save();
        // Set language field visible.
        \Drupal::service('entity_display.repository')->getViewDisplay('node', 'page', 'full')
            ->setComponent('langcode')
            ->save();
        // Create a node in Spanish.
        $node = $this->drupalCreateNode([
            'langcode' => 'es',
        ]);
        $this->drupalGet($node->toUrl());
        $this->assertText('Spanish', 'The language field is displayed properly.');
    }

}