make syncer track directories

src/test/common.js

@@ -0,0 +1,33 @@
+'use strict';
+
+var fs = require('fs'),
+    mkdirp = require('mkdirp'),
+    path = require('path'),
+    rimraf = require('rimraf');
+
+exports = module.exports = {
+    createTree: createTree
+};
+
+function createTree(root, obj) {
+    rimraf.sync(root);
+    mkdirp.sync(root);
+
+    function createSubTree(tree, curpath) {
+        for (var key in tree) {
+            if (typeof tree[key] === 'string') {
+                if (key.startsWith('link:')) {
+                    fs.symlinkSync(tree[key], path.join(curpath, key.slice(5)));
+                } else {
+                    fs.writeFileSync(path.join(curpath, key), tree[key], 'utf8');
+                }
+            } else {
+                fs.mkdirSync(path.join(curpath, key));
+                createSubTree(tree[key], path.join(curpath, key));
+            }
+        }
+    }
+
+    createSubTree(obj, root);
+}
+