Update to drupal 8.0.0-rc1. For more information, see https://www.drupal.org/node/2582663

vendor/symfony/http-kernel/Tests/CacheWarmer/CacheWarmerTest.php

@@ -0,0 +1,67 @@
+<?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\HttpKernel\Tests\CacheWarmer;
+
+use Symfony\Component\HttpKernel\CacheWarmer\CacheWarmer;
+
+class CacheWarmerTest extends \PHPUnit_Framework_TestCase
+{
+    protected static $cacheFile;
+
+    public static function setUpBeforeClass()
+    {
+        self::$cacheFile = tempnam(sys_get_temp_dir(), 'sf2_cache_warmer_dir');
+    }
+
+    public static function tearDownAfterClass()
+    {
+        @unlink(self::$cacheFile);
+    }
+
+    public function testWriteCacheFileCreatesTheFile()
+    {
+        $warmer = new TestCacheWarmer(self::$cacheFile);
+        $warmer->warmUp(dirname(self::$cacheFile));
+
+        $this->assertTrue(file_exists(self::$cacheFile));
+    }
+
+    /**
+     * @expectedException \RuntimeException
+     */
+    public function testWriteNonWritableCacheFileThrowsARuntimeException()
+    {
+        $nonWritableFile = '/this/file/is/very/probably/not/writable';
+        $warmer = new TestCacheWarmer($nonWritableFile);
+        $warmer->warmUp(dirname($nonWritableFile));
+    }
+}
+
+class TestCacheWarmer extends CacheWarmer
+{
+    protected $file;
+
+    public function __construct($file)
+    {
+        $this->file = $file;
+    }
+
+    public function warmUp($cacheDir)
+    {
+        $this->writeCacheFile($this->file, 'content');
+    }
+
+    public function isOptional()
+    {
+        return false;
+    }
+}