[ruby-talk:01788] size of Dir stream

I've been trying to make a procedure to remove a directory tree. I found
that if I use :

files=Dir.open(path)
if files.size<=2 # only `.' and '..'
    files.close()
    Dir.delete(path)
else
    ...
end

files.size is zero although when I print files.each it shows all files and
directories.
I solved it by using:

files=[]
Dir.foreach(path){|file| files.push(file)}

I was wondering is this normal behaviour?

Jasper