title: Ruby File::directory? Issues
body: <p>I am quite new to ruby but enjoying it so far quite immensely.  There are some things that have given me some trouble and the following is no exception.</p>
  
  <p>What I am trying to do here is create a sort of 'super-directory' by sub-classing 'Dir'.  I've added a method called 'subdirs' that is designed to list the directory object's files and push them into an array if the file is a directory itself.  The issue is, the results from my test (File.directory?) is strange - here is my method code:</p>
  
  <pre><code>  def subdirs
      subdirs = Array.new
      self.each do |x|
        puts "Evaluating file: #{x}"
        if File.directory?(x)
          puts "This file (#{x}) was considered a directory by File.directory?"
          subdirs.push(x)
          #yield(x) if block_given?
        end
      end
      return subdirs
    end
  </code></pre>
  
  <p>And strangely, even though there are plenty of directories in the directory I've chosen ("/tmp") - the result of this call only lists "." and ".."</p>
  
  <pre><code>puts "Testing new Directory custom class: FileOps/DirClass"
  
  nd   = Directory.new("/tmp")
  subs = nd.subdirs
  </code></pre>
  
  <p>And the results:</p>
  
  <pre><code>Evaluating file: mapping-root
  Evaluating file: orbit-jvxml
  Evaluating file: custom-directory
  Evaluating file: keyring-9x4JhZ
  Evaluating file: orbit-root
  Evaluating file: .
  This file (.) was considered a directory by File.directory?
  Evaluating file: .gdmFDB11U
  Evaluating file: .X0-lock
  Evaluating file: hsperfdata_mishii
  Evaluating file: .X11-unix
  Evaluating file: .gdm_socket
  Evaluating file: ..
  This file (..) was considered a directory by File.directory?
  Evaluating file: .font-unix
  Evaluating file: .ICE-unix
  Evaluating file: ssh-eqOnXK2441
  Evaluating file: vesystems-package
  Evaluating file: mapping-jvxml
  Evaluating file: hsperfdata_tomcat
  </code></pre>