Merge pull request #13 from evan-gu/fileSystem

fix bug of deleting the root

file_system/node.go

@@ -76,7 +76,7 @@ func (n *Node) Remove(recursive bool, callback func(path string)) error {
 	if !n.IsDir() { // file node: key-value pair
 		_, name := path.Split(n.Path)
 
-		if n.Parent.Children[name] == n {
+		if n.Parent != nil && n.Parent.Children[name] == n {
 			// This is the only pointer to Node object
 			// Handled by garbage collector
 			delete(n.Parent.Children, name)
@@ -102,7 +102,7 @@ func (n *Node) Remove(recursive bool, callback func(path string)) error {
 
 	// delete self
 	_, name := path.Split(n.Path)
-	if n.Parent.Children[name] == n {
+	if n.Parent != nil && n.Parent.Children[name] == n {
 		delete(n.Parent.Children, name)
 
 		if callback != nil {