N°2651 rollback gitignore for lib tests dirs

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

lib/symfony/cache/Tests/Fixtures/ExternalAdapter.php

@@ -0,0 +1,76 @@
+<?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\Fixtures;
+
+use Psr\Cache\CacheItemInterface;
+use Psr\Cache\CacheItemPoolInterface;
+use Symfony\Component\Cache\Adapter\ArrayAdapter;
+
+/**
+ * Adapter not implementing the {@see \Symfony\Component\Cache\Adapter\AdapterInterface}.
+ *
+ * @author Kévin Dunglas <dunglas@gmail.com>
+ */
+class ExternalAdapter implements CacheItemPoolInterface
+{
+    private $cache;
+
+    public function __construct()
+    {
+        $this->cache = new ArrayAdapter();
+    }
+
+    public function getItem($key)
+    {
+        return $this->cache->getItem($key);
+    }
+
+    public function getItems(array $keys = [])
+    {
+        return $this->cache->getItems($keys);
+    }
+
+    public function hasItem($key)
+    {
+        return $this->cache->hasItem($key);
+    }
+
+    public function clear()
+    {
+        return $this->cache->clear();
+    }
+
+    public function deleteItem($key)
+    {
+        return $this->cache->deleteItem($key);
+    }
+
+    public function deleteItems(array $keys)
+    {
+        return $this->cache->deleteItems($keys);
+    }
+
+    public function save(CacheItemInterface $item)
+    {
+        return $this->cache->save($item);
+    }
+
+    public function saveDeferred(CacheItemInterface $item)
+    {
+        return $this->cache->saveDeferred($item);
+    }
+
+    public function commit()
+    {
+        return $this->cache->commit();
+    }
+}