class RSpec::Mocks::Proxy

def add_message_expectation(location, method_name, opts={}, &block)
  meth_double = method_double[method_name]
  if null_object? && !block
    meth_double.add_default_stub(@error_generator, @expectation_ordering, location, opts) do
      @object
    end
  end
  meth_double.add_expectation @error_generator, @expectation_ordering, location, opts, &block
end