N°2651 rollback gitignore for lib tests dirs

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

lib/symfony/cache/Tests/Simple/ArrayCacheTest.php

@@ -0,0 +1,25 @@
+<?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\Simple;
+
+use Symfony\Component\Cache\Simple\ArrayCache;
+
+/**
+ * @group time-sensitive
+ */
+class ArrayCacheTest extends CacheTestCase
+{
+    public function createSimpleCache($defaultLifetime = 0)
+    {
+        return new ArrayCache($defaultLifetime);
+    }
+}