--- /dev/null
+<?php
+
+/*
+ * This file is part of the Behat Testwork.
+ * (c) Konstantin Kudryashov <ever.zet@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Behat\Testwork\ServiceContainer\Configuration;
+
+use Behat\Testwork\ServiceContainer\Extension;
+use Symfony\Component\Config\Definition\Builder\TreeBuilder;
+use Symfony\Component\Config\Definition\NodeInterface;
+
+/**
+ * Builds configuration tree using provided lists of core and custom extensions.
+ *
+ * @author Konstantin Kudryashov <ever.zet@gmail.com>
+ */
+final class ConfigurationTree
+{
+ /**
+ * Generates the configuration tree.
+ *
+ * @param Extension[] $extensions
+ *
+ * @return NodeInterface
+ */
+ public function getConfigTree(array $extensions)
+ {
+ $tree = new TreeBuilder();
+ $root = $tree->root('testwork');
+
+ foreach ($extensions as $extension) {
+ $extension->configure($root->children()->arrayNode($extension->getConfigKey()));
+ }
+
+ return $tree->buildTree();
+ }
+}