diff --git a/README b/README.rdoc
similarity index 94%
rename from README
rename to README.rdoc
index 4f8a33f..f283ce0 100644
--- a/README
+++ b/README.rdoc
@@ -3,9 +3,9 @@
 This is a simple pure-Ruby driver for the 10gen Mongo DB. For more information
 about Mongo, see http://www.mongodb.org.
 
-Note: this driver is still alpha quality. The API will change, as will the
+Note: this driver is still alpha quality. The API will change, as may the
 data saved to the database (especially primary key values). Do *_not_* use this
-for any production data.
+for any production data yet.
 
 
 = Demo
@@ -27,7 +27,7 @@ The tests assume that the Mongo database is running on the default port.
   $ rake rdoc
 
 Then open the file doc/index.html. (I need to figure out where to put this on
-the Web, or even how to publish this to the Wiki at
+the Web, or perhaps how to publish this to the Wiki at
 http://github.com/jimm/mongo-ruby-driver/wikis automatically.)
 
 
@@ -53,7 +53,7 @@ type
 = To Do
 
 * Tests that prove that this driver's ObjectID and Geir's Java version do the
-  same thing.
+  same thing. (I've done so manually.)
 
 * Capped collection support.
 
@@ -100,9 +100,3 @@ details.
 
 See http://www.gnu.org/licenses/ for a copy of the GNU Affero General Public
 License.
-
---
-# Local Variables:
-# mode:rdoc
-# End:
-++
diff --git a/lib/mongo/util/bson.rb b/lib/mongo/util/bson.rb
index 82af042..6632d01 100644
--- a/lib/mongo/util/bson.rb
+++ b/lib/mongo/util/bson.rb
@@ -3,35 +3,34 @@ require 'mongo/util/ordered_hash'
 require 'mongo/objectid'
 
 # See http://github.com/10gen/mongo/tree/master/db/jsobj.h
-# and 
 
 class BSON
 
-  EOO = 0                       # x
-  MAXKEY = -1                   # x
-  NUMBER = 1                    # x t
-  STRING = 2                    # x t
-  OBJECT = 3                    # x t
+  MINKEY = -1
+  EOO = 0
+  NUMBER = 1
+  STRING = 2
+  OBJECT = 3
   ARRAY = 4
   BINARY = 5
   UNDEFINED = 6
-  OID = 7                       # x
-  BOOLEAN = 8                   # x t
-  DATE = 9                      # x t
-  NULL = 10                     # x t
+  OID = 7
+  BOOLEAN = 8
+  DATE = 9
+  NULL = 10
   REGEX = 11
   REF = 12
   CODE = 13
   SYMBOL = 14
   CODE_W_SCOPE = 15
   NUMBER_INT = 16
+  MAXKEY = 127
 
   def self.serialize_cstr(buf, val)
     buf.put_array(val.to_s.unpack("C*") + [0])
   end
 
   def initialize
-    @private_buf = ByteBuffer.new
     @buf = ByteBuffer.new
   end
 
@@ -67,8 +66,10 @@ class BSON
         serialize_date_element(@buf, k, v)
       when NULL
         serialize_null_element(@buf, k)
+      when BINARY, UNDEFINED, REF, SYMBOL, CODE_W_SCOPE
+        raise "unimplemented type #{type}"
       else
-        raise "Unhandled Type #{type}"
+        raise "unhandled type #{type}"
       end
     }
     serialize_eoo_element(@buf)
@@ -76,15 +77,17 @@ class BSON
     self
   end
 
-  def deserialize(buf)
-    @buf = ByteBuffer.new(buf.to_a)
+  def deserialize(buf=nil)
+    # If buf is nil, use @buf, assumed to contain already-serialized BSON.
+    # This is only true during testing.
+    @buf = ByteBuffer.new(buf.to_a) if buf
     @buf.rewind
     @buf.get_int                # eat message size
     doc = {}
     while @buf.more?
       type = @buf.get
       case type
-      when STRING
+      when STRING, CODE
         key = deserialize_element_name(@buf)
         doc[key] = deserialize_string_data(@buf)
       when NUMBER
@@ -302,7 +305,7 @@ class BSON
     when XGen::Mongo::Driver::ObjectID
       OID
     when true, false
-      Boolean
+      BOOLEAN
     when Time
       DATE
     when Hash
diff --git a/lib/mongo/util/byte_buffer.rb b/lib/mongo/util/byte_buffer.rb
index 55ef39c..dcede06 100644
--- a/lib/mongo/util/byte_buffer.rb
+++ b/lib/mongo/util/byte_buffer.rb
@@ -49,8 +49,14 @@ class ByteBuffer
     @cursor += array.length
   end
 
-  def put_int(i, offset=nil)
-    put_array([i].pack(@int_pack_order).split(//).collect{|c| c[0]}, offset)
+  if RUBY_VERSION >= '1.9'
+    def put_int(i, offset=nil)
+      put_array([i].pack(@int_pack_order).split(//).collect{|c| c.bytes.first}, offset)
+    end
+  else
+    def put_int(i, offset=nil)
+      put_array([i].pack(@int_pack_order).split(//).collect{|c| c[0]}, offset)
+    end
   end
 
   def put_long(i, offset=nil)
@@ -64,8 +70,14 @@ class ByteBuffer
     end
   end
 
-  def put_double(d, offset=nil)
-    put_array([d].pack(@double_pack_order).split(//), offset)
+  if RUBY_VERSION >= '1.9'
+    def put_double(d, offset=nil)
+      put_array([d].pack(@double_pack_order).split(//).collect{|c| c.bytes.first}, offset)
+    end
+  else
+    def put_double(d, offset=nil)
+      put_array([d].pack(@double_pack_order).split(//).collect{|c| c[0]}, offset)
+    end
   end
 
   # If +size+ == 1, returns one byte. Else returns array of bytes of length
diff --git a/tests/test_bson.rb b/tests/test_bson.rb
new file mode 100644
index 0000000..da38a3b
--- /dev/null
+++ b/tests/test_bson.rb
@@ -0,0 +1,77 @@
+$LOAD_PATH[0,0] = File.join(File.dirname(__FILE__), '..', 'lib')
+require 'mongo'
+require 'test/unit'
+
+# NOTE: assumes Mongo is running
+class BSONTest < Test::Unit::TestCase
+
+  def setup
+    @b = BSON.new
+  end
+
+  def test_string
+    doc = {'doc' => 'hello, world'}
+    @b.serialize(doc)
+    assert_equal doc, @b.deserialize
+  end
+
+  def test_code
+    doc = {'$where' => 'this.a.b < this.b'}
+    @b.serialize(doc)
+    assert_equal doc, @b.deserialize
+  end
+
+  def test_number
+    doc = {'doc' => 41.99}
+    @b.serialize(doc)
+    assert_equal doc, @b.deserialize
+  end
+
+  def test_int
+    doc = {'doc' => 42}
+    @b.serialize(doc)
+    assert_equal doc, @b.deserialize
+  end
+
+  def test_object
+    doc = {'doc' => {'age' => 42, 'name' => 'Spongebob', 'shoe_size' => 9.5}}
+    @b.serialize(doc)
+    assert_equal doc, @b.deserialize
+  end
+
+  def test_oid
+    doc = {'doc' => XGen::Mongo::Driver::ObjectID.new}
+    @b.serialize(doc)
+    assert_equal doc, @b.deserialize
+  end
+
+  def test_array
+    doc = {'doc' => [1, 2, 'a', 'b']}
+    @b.serialize(doc)
+    assert_equal doc, @b.deserialize
+  end
+
+  def test_regex
+    doc = {'doc' => /foobar/i}
+    @b.serialize(doc)
+    assert_equal doc, @b.deserialize
+  end
+
+  def test_boolean
+    doc = {'doc' => true}
+    @b.serialize(doc)
+    assert_equal doc, @b.deserialize
+  end
+
+  def test_date
+    doc = {'date' => Time.now}
+    @b.serialize(doc)
+    doc2 = @b.deserialize
+    # Mongo only stores seconds, so comparing raw Time objects will fail
+    # because the fractional seconds will be different.
+    assert_equal doc['date'].to_i, doc2['date'].to_i
+  end
+
+  def test_null
+  end
+end
diff --git a/tests/test_byte_buffer.rb b/tests/test_byte_buffer.rb
index 63ac6d9..5025fab 100644
--- a/tests/test_byte_buffer.rb
+++ b/tests/test_byte_buffer.rb
@@ -32,6 +32,12 @@ class ByteBufferTest < Test::Unit::TestCase
     assert_equal 1027, @buf.get_long
   end
 
+  def test_get_double
+    @buf.put_double 41.2
+    @buf.rewind
+    assert_equal 41.2, @buf.get_double
+  end
+
   def test_rewrite
     @buf.put_int(0)
     @buf.rewind