match the chunk size in the 10gen mongo driver to solve connection issues when saving large files, and get tests working again

lib/mongoid-grid_fs.rb

@@ -58,6 +58,8 @@
 #
   module Mongoid
     class GridFS
+      DEFAULT_CHUNK_SIZE = 256 * 1024
+
       class << GridFS
         attr_accessor :namespace
         attr_accessor :file_model
@@ -293,7 +295,7 @@
           field(:contentType, :type => String, :default => 'application/octet-stream')
 
           field(:length, :type => Integer, :default => 0)
-          field(:chunkSize, :type => Integer, :default => (256 * (2 ** 20)))
+          field(:chunkSize, :type => Integer, :default => DEFAULT_CHUNK_SIZE)
           field(:uploadDate, :type => Date, :default => Time.now.utc)
           field(:md5, :type => String, :default => Digest::MD5.hexdigest(''))
 

test/helper.rb

@@ -2,6 +2,7 @@
 require 'pp'
 require_relative 'testing'
 require_relative '../lib/mongoid-sequence.rb'
+require_relative '../lib/mongoid-grid_fs.rb'
 
 Mongoid.configure do |config|
   config.connect_to('mongoid-sequence')

test/mongoid-grid_fs_test.rb

@@ -70,7 +70,7 @@ Testing Mongoid::GridFs do
       path = 'a.rb'
       data = IO.read(__FILE__)
 
-      sio = SIO.new(path, data) 
+      sio = StringIO.new(data) 
 
       g = assert{ GridFs[path] = sio and GridFs[path] }
 
@@ -79,7 +79,7 @@ Testing Mongoid::GridFs do
 
       before = GridFs::File.count
 
-      assert{ GridFs[path] = SIO.new(path, 'foobar') }
+      assert{ GridFs[path] = StringIO.new('foobar') }
       assert{ GridFs[path].data == 'foobar' }
 
       after = GridFs::File.count