Postgres: Invalid default value getting from character varying columns.

Migrating script:

    create_table "order_users", :force => true do |t|

  t.string   "username",      :limit => 50
  t.string   "email_address", :limit => 50, :default => "test1", :null => false
  t.string   "password",      :limit => 20
  t.datetime "created_on"
  t.string   "first_name",    :limit => 50, :default => "test2", :null => false
  t.string   "last_name",     :limit => 50, :default => "test3", :null => false
end</code>

Creating new object:

>> OrderUser.new
=> #<OrderUser id: nil, username: nil, email_address: "'test1'::character varying", password: nil, created_on: nil, first_name: "'test2'::character varying", last_name: "'test3'::character varying">

Rails 2.3.2
Postgresql 8.3.7
postgres gem (0.7.9.2008.01.28)