backtrace

/Library/Ruby/Gems/1.8/gems/activesupport-2.3.1/lib/active_support/dependencies.rb:440:in `load_missing_constant': uninitialized constant ActiveRecord::Validations (NameError)
	from /Library/Ruby/Gems/1.8/gems/activesupport-2.3.1/lib/active_support/dependencies.rb:80:in `const_missing'
	from /Library/Ruby/Gems/1.8/gems/activerecord-2.3.1/lib/active_record/base.rb:3140
	from /Library/Ruby/Gems/1.8/gems/activerecord-2.3.1/lib/active_record/base.rb:3138:in `class_eval'
	from /Library/Ruby/Gems/1.8/gems/activerecord-2.3.1/lib/active_record/base.rb:3138
	from /Library/Ruby/Gems/1.8/gems/activerecord-2.3.1/lib/active_record/validations.rb:9
	from ./lib/money_handler.rb:19:in `enable'
	from ./lib/money_handler.rb:26
	from /Library/Ruby/Site/1.8/rubygems/custom_require.rb:31:in `gem_original_require'
	 ... 10 levels...
	from /Library/Ruby/Gems/1.8/gems/rspec-1.1.12/lib/spec/runner/example_group_runner.rb:14:in `load_files'
	from /Library/Ruby/Gems/1.8/gems/rspec-1.1.12/lib/spec/runner/options.rb:94:in `run_examples'
	from /Library/Ruby/Gems/1.8/gems/rspec-1.1.12/lib/spec/runner/command_line.rb:9:in `run'
	from /Library/Ruby/Gems/1.8/gems/rspec-1.1.12/bin/spec:4

money_handler.rb

require 'rubygems'
require 'active_record'
require 'active_support'

# punch the duck
module MoneyHandler

  module Validations
    module ClassMethods
      def validate_local_numericality_of(*args)
        false
      end      
    end
  end  

  class << self
    def enable
      ActiveRecord::Validations::ClassMethods.send :include,  MoneyHandler::Validations::ClassMethods
    end
  end
end

if defined?(ActiveRecord) && defined?(ActiveRecord::Validations)
  MoneyHandler.enable
end