Rspec:方法get: show, ArgumentError:参数数量错误(1 for 0)

Question

我运行test rspec spec/controllers/lost_pets_controller_spec。get:show, id: lost_pet:

require 'rails_helper'
RSpec.describe LostPetsController, type: :controller do
  let(:lost_pet) { create(:lost_pet) }
  describe "Get #Index" do
    let(:lost_pets) { create_list(:lost_pet, 2) }
    before{ get :index }
    it "populates an array of all lost_pets" do
      expect(assigns(:lost_pets)).to match_array(lost_pets)    
    end
    it "renders index view" do
      expect(response).to render_template(:index) 
    end
  end
  describe 'Get #show' do
    before do
      get :show, id: lost_pet
    end
    it 'assings the requested lost pet to @lost_pet' do
      expect(assigns(:lost_pet)).to eq lost_pet
    end
    it 'renders show view' do
      expect(response).to render_template(:show)
    end
  end
end

lostpetscontroller.rb

class LostPetsController < ApplicationController
  before_action :load_lost_pet, only: [:show]
  respond_to :html
  def index
      @lost_pets = LostPet.all
  end
  def show
    @lost_pet
  end

  private
  def load_lost_pet
    @lost_pet = LostPet.find(params(:id))
  end
  def lost_pet_params
    params.require(:lost_pet).permit([:id, :name, :type_pet, :breed, :gender, :size,
      :colour, :age, :age_unit, :description, :collar_description, :desexed, 
      :microchipped, :microchip_number, :date_missing, :rewald, :image, :adress_lost,
      :name_host, :telephone, :email ])
  end
end

登录终端:

LostPetsController Get #show assings the requested lost pet to @lost_pet
     Failure/Error: get :show, id: lost_pet
     ArgumentError:
       wrong number of arguments (1 for 0)
     # /usr/local/rvm/gems/ruby-2.2.1/gems/actionpack-4.2.1/lib/action_controller/metal/strong_parameters.rb:656:in `params'
     # ./app/controllers/lost_pets_controller.rb:18:in `load_lost_pet'

为什么操作显示的参数号码错误?如何解决这个问题?谢谢你的帮助。

Answer 1

修改行:

@lost_pet = LostPet.find(params(:id))

:

@lost_pet = LostPet.find(params[:id])

(注意方括号)

Answer 2

错误信息:

 ArgumentError:
   wrong number of arguments (1 for 0)

意味着你正在调用一个方法并提供一个参数，但该方法不接受任何参数，因此"1 for 0"。哪一种方法?它是backtrace中的第一个:

/usr/local/rvm/gems/ruby-2.2.1/gems/actionpack-4.2.1/lib/action_controller/metal/strong_parameters.rb:656:in `params'

params返回参数哈希值。您可以在控制器中快速查看错误原因:

@lost_pet = LostPet.find(params(:id))

通过使用方括号代替父括号来修复它:

@lost_pet = LostPet.find(params[:id])