Failed create!

gistfile1.rb

require 'rubygems'
gem 'dm-core', '0.10.0'
gem 'dm-validations', '0.10.0'
require 'dm-core'
require 'dm-validations'
 
DataMapper.setup(:default, 'postgres://tpitale@localhost/test_create_fail')
 
class User1
  include DataMapper::Resource

  property :id, Serial
  property :name, String, :nullable => false
end

class User2
  include DataMapper::Resource

  property :id, Serial

  validates_with_block(:test) {always_fails}
  
  def always_fails
    [false, "You are bound to fail!"]
  end
end

DataObjects::Postgres.logger = DataObjects::Logger.new(STDOUT, 0)

DataMapper.auto_migrate!

# correctly returns false
user = User2.new
puts user.valid?

# does not fail
puts User2.create!.id

# correctly returns false
user = User1.new
puts user.valid?

# only fails because of database constraints
# also, blows up
puts User1.create!.id