N°2651 rollback gitignore for lib tests dirs

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

lib/symfony/cache/Tests/Traits/PdoPruneableTrait.php

@@ -0,0 +1,34 @@
+<?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\Traits;
+
+trait PdoPruneableTrait
+{
+    protected function isPruned($cache, $name)
+    {
+        $o = new \ReflectionObject($cache);
+
+        if (!$o->hasMethod('getConnection')) {
+            self::fail('Cache does not have "getConnection()" method.');
+        }
+
+        $getPdoConn = $o->getMethod('getConnection');
+        $getPdoConn->setAccessible(true);
+
+        /** @var \Doctrine\DBAL\Statement $select */
+        $select = $getPdoConn->invoke($cache)->prepare('SELECT 1 FROM cache_items WHERE item_id LIKE :id');
+        $select->bindValue(':id', sprintf('%%%s', $name));
+        $select->execute();
+
+        return 0 === \count($select->fetchAll(\PDO::FETCH_COLUMN));
+    }
+}