diff --git a/bin/validate b/bin/validate
new file mode 100755
index 0000000..2c5d8ba
--- /dev/null
+++ b/bin/validate
@@ -0,0 +1,15 @@
+#!/usr/bin/env ruby
+#
+# Reads a .xson file (XML that describes a Mongo-type document) from stdin and
+# writes the corresponding BSON to stdout.
+#
+# This script is used by the mongo-qa project
+# (http://github.com/mongodb/mongo-qa).
+
+$LOAD_PATH[0,0] = File.join(File.dirname(__FILE__), '..', 'lib')
+require 'mongo'
+require 'mongo/util/xml_to_ruby'
+
+obj = XMLToRuby.new.xml_to_ruby($stdin)
+bson = BSON.new.serialize(obj).to_a
+bson.each { |b| putc(b) }
diff --git a/lib/mongo/util/xml_to_ruby.rb b/lib/mongo/util/xml_to_ruby.rb
new file mode 100644
index 0000000..18446ee
--- /dev/null
+++ b/lib/mongo/util/xml_to_ruby.rb
@@ -0,0 +1,96 @@
+# --
+# Copyright (C) 2008-2009 10gen Inc.
+#
+# This program is free software: you can redistribute it and/or modify it
+# under the terms of the GNU Affero General Public License, version 3, as
+# published by the Free Software Foundation.
+#
+# This program is distributed in the hope that it will be useful, but WITHOUT
+# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+# FITNESS FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License
+# for more details.
+#
+# You should have received a copy of the GNU Affero General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.
+# ++
+
+require 'rexml/document'
+require 'mongo'
+
+# Converts a .bson file (an XML file that describes a Mongo-type document) to
+# an OrderedHash.
+class XMLToRuby
+
+  include XGen::Mongo::Driver
+
+  def xml_to_ruby(io)
+    doc = REXML::Document.new(io)
+    doc_to_ruby(doc.root.elements['doc'])
+  end
+
+  protected
+
+  def element_to_ruby(e)
+    type = e.name
+    child = e.elements[1]
+    case type
+    when 'oid'
+      ObjectID.from_string(e.text)
+    when 'ref'
+      dbref_to_ruby(e.elements)
+    when 'int'
+      e.text.to_i
+    when 'number'
+      e.text.to_f
+    when 'string', 'code'
+      e.text.to_s
+    when 'boolean'
+      e.text.to_s == 'true'
+    when 'array'
+      array_to_ruby(e.elements)
+    when 'date'
+      Time.at(e.text.to_f / 1000.0)
+    when 'regex'
+      regex_to_ruby(e.elements)
+    when 'null'
+      nil
+    when 'doc'
+      doc_to_ruby(e)
+    else
+      raise "Unknown type #{type} in element with name #{e.attributes['name']}"
+    end
+  end
+
+  def doc_to_ruby(element)
+    oh = OrderedHash.new
+    element.elements.each { |e| oh[e.attributes['name']] = element_to_ruby(e) }
+    oh
+  end
+
+  def array_to_ruby(elements)
+    a = []
+    elements.each { |e|
+      index_str = e.attributes['name']
+      a[index_str.to_i] = element_to_ruby(e)
+    }
+    a
+  end
+
+  def regex_to_ruby(elements)
+    pattern = elements['pattern'].text
+    options_str = elements['options'].text || ''
+
+    options = 0
+    options |= Regexp::IGNORECASE if options_str.include?('i')
+    options |= Regexp::MULTILINE if options_str.include?('m')
+    options |= Regexp::EXTENDED if options_str.include?('x')
+    Regexp.new(pattern, options)
+  end
+
+  def dbref_to_ruby(elements)
+    ns = elements['ns'].text
+    oid_str = elements['oid'].text
+    DBRef.new(nil, nil, nil, ns, ObjectID.from_string(oid_str))
+  end
+
+end
diff --git a/tests/test_round_trip.rb b/tests/test_round_trip.rb
index 9fbd3b7..03ab613 100644
--- a/tests/test_round_trip.rb
+++ b/tests/test_round_trip.rb
@@ -1,7 +1,7 @@
 HERE = File.dirname(__FILE__)
 $LOAD_PATH[0,0] = File.join(HERE, '..', 'lib')
 require 'mongo'
-require 'rexml/document'
+require 'mongo/util/xml_to_ruby'
 require 'test/unit'
 
 # For each xml/bson file in the data subdirectory, we turn the XML into an
@@ -16,80 +16,14 @@ class RoundTripTest < Test::Unit::TestCase
     unless @@ruby
       names = Dir[File.join(HERE, 'data', '*.xml')].collect {|f| File.basename(f).sub(/\.xml$/, '') }
       @@ruby = {}
-      names.each { |name| @@ruby[name] = xml_to_ruby(name) }
+      names.each { |name|
+        File.open(File.join(HERE, 'data', "#{name}.xml")) { |f|
+          @@ruby[name] = XMLToRuby.new.xml_to_ruby(f)
+        }
+      }
     end
   end
 
-  def xml_to_ruby(name)
-    File.open(File.join(HERE, 'data', "#{name}.xml")) { |f|
-      doc = REXML::Document.new(f)
-      doc_to_ruby(doc.root.elements['doc'])
-    }
-  end
-
-  def element_to_ruby(e)
-    type = e.name
-    child = e.elements[1]
-    case type
-    when 'oid'
-      ObjectID.from_string(e.text)
-    when 'ref'
-      dbref_to_ruby(e.elements)
-    when 'int'
-      e.text.to_i
-    when 'number'
-      e.text.to_f
-    when 'string', 'code'
-      e.text.to_s
-    when 'boolean'
-      e.text.to_s == 'true'
-    when 'array'
-      array_to_ruby(e.elements)
-    when 'date'
-      Time.at(e.text.to_f / 1000.0)
-    when 'regex'
-      regex_to_ruby(e.elements)
-    when 'null'
-      nil
-    when 'doc'
-      doc_to_ruby(e)
-    else
-      raise "Unknown type #{type} in element with name #{e.attributes['name']}"
-    end
-  end
-
-  def doc_to_ruby(element)
-    oh = OrderedHash.new
-    element.elements.each { |e| oh[e.attributes['name']] = element_to_ruby(e) }
-    oh
-  end
-
-  def array_to_ruby(elements)
-    a = []
-    elements.each { |e|
-      index_str = e.attributes['name']
-      a[index_str.to_i] = element_to_ruby(e)
-    }
-    a
-  end
-
-  def regex_to_ruby(elements)
-    pattern = elements['pattern'].text
-    options_str = elements['options'].text || ''
-
-    options = 0
-    options |= Regexp::IGNORECASE if options_str.include?('i')
-    options |= Regexp::MULTILINE if options_str.include?('m')
-    options |= Regexp::EXTENDED if options_str.include?('x')
-    Regexp.new(pattern, options)
-  end
-
-  def dbref_to_ruby(elements)
-    ns = elements['ns'].text
-    oid_str = elements['oid'].text
-    DBRef.new(nil, nil, nil, ns, ObjectID.from_string(oid_str))
-  end
-
   # Round-trip comparisons of Ruby-to-BSON and back.
   # * Take the objects that were read from XML
   # * Turn them into BSON bytes