class ChainedMock < RSpec::Mocks::Mock
  class WrongMethodCalled < StandardError; end

  def method_missing meth, *args, &block
    raise WrongMethodCalled.new "expected method #{@next} to be next in the chain, but instead received #{meth}"
  end

  def should_receive(meth, opts = {}, &block)
    @next = meth
    super
  end
end

class Object
  def should_receive_chain *args
    if args.size == 1
      should_receive(args[0], "missing call to method #{args[0]} in chained expectation")
    else
      exp = ChainedMock.new(:chained_expectation)
      top = args.slice!(0)
      should_receive(top, "missing call to method #{top} in chained expectation").and_return(exp)
      if self.class != ChainedMock
        args.each_with_index do |arg, idx|
          stub(arg) do
            raise ChainedMock::WrongMethodCalled.new "expected method #{top} to be first in the chain, but instead received #{arg}"
          end
        end
      end
      exp.should_receive_chain *args
    end
  end
end


# usage
User.should_receive_chain(:registered, :logged_in_once).and_return([user])