ThemeHookTest.php

<?php

declare (strict_types=1);
namespace Drupal\Tests\system\Kernel\Theme;

use Drupal\Core\Theme\ThemeInitializationInterface;
use Drupal\KernelTests\KernelTestBase;
use PHPUnit\Framework\Attributes\Group;
use PHPUnit\Framework\Attributes\RunTestsInSeparateProcesses;

/**
 * Tests low-level theme functions.
 */
class ThemeHookTest extends KernelTestBase {
  
  /**
   * {@inheritdoc}
   */
  public function setUp() : void {
    parent::setUp();
    \Drupal::service('theme_installer')->install([
      'procedural_hook_theme',
    ]);
    \Drupal::theme()->setActiveTheme(\Drupal::service(ThemeInitializationInterface::class)->initTheme('procedural_hook_theme'));
  }
  
  /**
   * Tests that procedural hooks are collected and executed.
   */
  public function testProceduralHookCollection() : void {
    $args = [];
    \Drupal::theme()->alter('procedural', $args);
    $this->assertEquals([
      'Procedural theme hook executed.',
    ], $args);
  }
  
  /**
   * Tests that procedural hooks with #[LegacyHook] are properly ignored.
   */
  public function testLegacyHookInThemes() : void {
    $args = [];
    \Drupal::theme()->alter('procedural_legacy', $args);
    $this->assertEquals([
      'OOP theme hook executed.',
    ], $args);
  }

}