MemDir now reports a size

httpFs.go

diff --git a/httpFs.go b/httpFs.go
index af44344..a08f0bd 100644
--- a/httpFs.go
+++ b/httpFs.go
@@ -36,6 +36,7 @@
 	if dir == "" {
 		dir = "."
 	}
+
 	f, err := d.fs.Open(filepath.Join(dir, filepath.FromSlash(path.Clean("/"+name))))
 	if err != nil {
 		return nil, err

memfile.go

diff --git a/memfile.go b/memfile.go
index fcf80d2..4815c6b 100644
--- a/memfile.go
+++ b/memfile.go
@@ -191,8 +191,13 @@
 
 // Implements os.FileInfo
 func (s *InMemoryFileInfo) Name() string       { return s.file.Name() }
-func (s *InMemoryFileInfo) Size() int64        { return int64(len(s.file.data)) }
 func (s *InMemoryFileInfo) Mode() os.FileMode  { return s.file.mode }
 func (s *InMemoryFileInfo) ModTime() time.Time { return s.file.modtime }
 func (s *InMemoryFileInfo) IsDir() bool        { return s.file.dir }
 func (s *InMemoryFileInfo) Sys() interface{}   { return nil }
+func (s *InMemoryFileInfo) Size() int64 {
+	if s.IsDir() {
+		return int64(42)
+	}
+	return int64(len(s.file.data))
+}