== Class#cattr

  require 'facets/module/cattr'

  class CAttrMockObject
    def initialize
      @@a = 10
    end
    def b ; @@b ; end
  end

  Exception.refute.raised? do
    CAttrMockObject.class_eval{ cattr :a }
  end
  t = CAttrMockObject.new
  t.a.assert == 10

== Class#cattr_reader

  Exception.refute.raised? do
    CAttrMockObject.class_eval { cattr_reader :a }
  end
  t = CAttrMockObject.new
  t.a.assert == 10

== Class#cattr_writer

  Exception.refute.raised? do
    CAttrMockObject.class_eval { cattr_writer :b }
  end
  t = CAttrMockObject.new
  t.b = 5
  t.b.assert == 5

== Class#cattr_accessor

  Exception.refute.raised? do
    CAttrMockObject.class_eval { cattr_accessor :c }
  end
  t = CAttrMockObject.new
  t.c = 50
  t.c.assert == 50