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

vendor/symfony/dependency-injection/Tests/Fixtures/includes/foo.php

@@ -0,0 +1,38 @@
+<?php
+
+namespace Bar;
+
+class FooClass
+{
+    public $foo, $moo;
+
+    public $bar = null, $initialized = false, $configured = false, $called = false, $arguments = array();
+
+    public function __construct($arguments = array())
+    {
+        $this->arguments = $arguments;
+    }
+
+    public static function getInstance($arguments = array())
+    {
+        $obj = new self($arguments);
+        $obj->called = true;
+
+        return $obj;
+    }
+
+    public function initialize()
+    {
+        $this->initialized = true;
+    }
+
+    public function configure()
+    {
+        $this->configured = true;
+    }
+
+    public function setBar($value = null)
+    {
+        $this->bar = $value;
+    }
+}