CachedStorageTest.php

<?php

namespace Drupal\Tests\Core\Config;

use Drupal\Tests\UnitTestCase;
use Drupal\Core\Config\CachedStorage;
use Drupal\Core\Cache\NullBackend;

/**
 * Tests the interaction of cache and file storage in CachedStorage.
 *
 * @group Config
 */
class CachedStorageTest extends UnitTestCase {
    
    /**
     * @var \Drupal\Core\Cache\CacheFactoryInterface|\PHPUnit\Framework\MockObject\MockObject
     */
    protected $cacheFactory;
    
    /**
     * Tests listAll static cache.
     */
    public function testListAllStaticCache() {
        $prefix = __FUNCTION__;
        $storage = $this->createMock('Drupal\\Core\\Config\\StorageInterface');
        $response = [
            "{$prefix}." . $this->randomMachineName(),
            "{$prefix}." . $this->randomMachineName(),
        ];
        $storage->expects($this->once())
            ->method('listAll')
            ->with($prefix)
            ->willReturn($response);
        $cache = new NullBackend(__FUNCTION__);
        $cachedStorage = new CachedStorage($storage, $cache);
        $this->assertEquals($response, $cachedStorage->listAll($prefix));
        $this->assertEquals($response, $cachedStorage->listAll($prefix));
    }

}