in beta9

code:

require 'rubygems'
require 'mongoid'

Mongoid.database = Mongo::Connection.new("localhost").db("my_test")

class Test
include Mongoid::Document
field :name
end

t = Test.new(:name => "test_name")
t.save

output:

ruby mongoid_test_case.rb
/usr/lib/ruby/gems/1.8/gems/mongoid-2.0.0.beta9/lib/mongoid/persistence/insert.rb:25:in `invalid?': wrong number of arguments (1 for 0) (ArgumentError)
from /usr/lib/ruby/gems/1.8/gems/mongoid-2.0.0.beta9/lib/mongoid/persistence/insert.rb:25:in `persist'
from /usr/lib/ruby/gems/1.8/gems/mongoid-2.0.0.beta9/lib/mongoid/persistence.rb:40:in `insert'
from /usr/lib/ruby/gems/1.8/gems/mongoid-2.0.0.beta9/lib/mongoid/persistence.rb:122:in `save'
from mongoid_test_case.rb:12