BlockTemplateSuggestionsTest.php

<?php

namespace Drupal\Tests\block\Kernel;

use Drupal\block\Entity\Block;
use Drupal\KernelTests\KernelTestBase;

/**
 * Tests the block_theme_suggestions_block() function.
 *
 * @group block
 */
class BlockTemplateSuggestionsTest extends KernelTestBase {
    
    /**
     * {@inheritdoc}
     */
    protected static $modules = [
        'block',
        'system',
    ];
    
    /**
     * Tests template suggestions from block_theme_suggestions_block().
     */
    public function testBlockThemeHookSuggestions() {
        $this->installConfig([
            'system',
        ]);
        // Create a block using a plugin with derivative to be preprocessed.
        $block = Block::create([
            'plugin' => 'system_menu_block:admin',
            'region' => 'footer',
            'id' => 'machinename',
        ]);
        $variables = [];
        
        /** @var \Drupal\Core\Block\BlockPluginInterface $plugin */
        $plugin = $block->getPlugin();
        $variables['elements']['#configuration'] = $plugin->getConfiguration();
        $variables['elements']['#plugin_id'] = $plugin->getPluginId();
        $variables['elements']['#id'] = $block->id();
        $variables['elements']['#base_plugin_id'] = $plugin->getBaseId();
        $variables['elements']['#derivative_plugin_id'] = $plugin->getDerivativeId();
        $variables['elements']['content'] = [];
        $suggestions = block_theme_suggestions_block($variables);
        $this->assertSame([
            'block__system',
            'block__system_menu_block',
            'block__system_menu_block__admin',
            'block__machinename',
        ], $suggestions);
    }

}