Added Unittests for cache

fixed Lock & Cache bugs

tests/src/Core/Cache/DatabaseCacheDriverTest.php

@@ -0,0 +1,25 @@
+<?php
+
+namespace Friendica\Test\src\Core\Cache;
+
+use Friendica\Core\Cache\CacheDriverFactory;
+
+class DatabaseCacheDriverTest extends CacheTest
+{
+	/**
+	 * @var \Friendica\Core\Cache\IMemoryCacheDriver
+	 */
+	private $cache;
+
+	protected function getInstance()
+	{
+		$this->cache = CacheDriverFactory::create('database');
+		return $this->cache;
+	}
+
+	public function tearDown()
+	{
+		$this->cache->clear();
+		parent::tearDown();
+	}
+}