class PropertyHash < Hash
  def method_missing(name, *args, &block)
    return self[name.to_s] if include?(name.to_s) && args.size == 0
    return !!self[$1] if name.to_s =~ /^(.+)\?$/ && include?($1) && args.size == 0
    if name.to_s =~ /^(.+)\=$/ && include?($1) && args.size == 1
      self[$1] = args.first
      return
    end
    super
  end

  def respond_to?(name)
    return true if include?(name.to_s)
    return true if name.to_s =~ /^(.+)[\?\=]$/ && include?($1)
    super
  end
end


class YourModel
  attr_accessor :access

  def initialize
    @access = PropertyHash.new
  end
end

def assert(msg = nil)
  raise "Assertion failed: #{msg || 'Unknown'}" unless yield
end

obj = YourModel.new

obj.access['fault'] = :yes

assert('fault getter') do
  obj.access.fault == :yes
end

assert('fault test') do
  obj.access.fault?
end

assert('fault setter') do
  obj.access.fault = :no
  obj.access.fault == :no
end

assert('responds to getter') do
  obj.access.respond_to?(:fault)
end

assert('responds to setter') do
  obj.access.respond_to?(:fault=)
end

assert('responds to test') do
  obj.access.respond_to?(:fault?)
end