class RSpec::Mocks::Implementation

def actions
  [initial_action, inner_action, terminal_action].compact
end

def arg_slice_for(args, arity)
  if arity >= 0
    args.slice(0, arity)
  else
    args
  end
end

def call(*args, &block)
  actions.map do |action|
    action.call(*arg_slice_for(args, action.arity), &block)
  end.last
end

def present?
  actions.any?
end