N°2651 rollback gitignore for lib tests dirs

Too dangerous ! We'll work properly on this but for 2.8

lib/symfony/cache/Tests/Adapter/PredisClusterAdapterTest.php

@@ -0,0 +1,26 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Cache\Tests\Adapter;
+
+class PredisClusterAdapterTest extends AbstractRedisAdapterTest
+{
+    public static function setUpBeforeClass()
+    {
+        parent::setUpBeforeClass();
+        self::$redis = new \Predis\Client([['host' => getenv('REDIS_HOST')]]);
+    }
+
+    public static function tearDownAfterClass()
+    {
+        self::$redis = null;
+    }
+}