lambda do count应该已经被改变了1，但被改变了0

Question

我测试我的应用程序以创建一个新的用户汽车，稍后用户创建新汽车应用程序必须重定向到user_car_path（我发布我的路线） ：

user_cars GET /users/:user_id/cars(.:format)        cars#index 
         POST /users/:user_id/cars(.:format)        cars#create 
     new_user_car GET /users/:user_id/cars/new(.:format)       cars#new 
     edit_user_car GET /users/:user_id/cars/:id/edit(.:format)      cars#edit 
      user_car GET /users/:user_id/cars/:id(.:format)       cars#show 
         PUT /users/:user_id/cars/:id(.:format)       cars#update 
         DELETE /users/:user_id/cars/:id(.:format)       cars#destroy 

所以我测试我的应用程序与此rspec的：

describe "POST 'create' car" do 

describe "car created success" do 
    before(:each) do 
      @user = User.create!(:email => "foo@example.com", :password => "foobar", :password_confirmation => "foobar") 
      @car = Car.create!(:brand => "example", :color => "foobar", :model => "foobar", :year =>"2012") 
    end 

    it "should create a car" do 
    lambda do 
     post :create, :cars => @car, :user_id => @user.id 
    end.should change(Car, :count).by(1) 
    end 

    it "should redirect to the user cars page" do 
    post :create, :cars => @car, :user_id => @user.id 
    response.should redirect_to user_car_path(@user, @car) 
    end 
end 
end 

，但我得到了2个错误

Failures: 

1) CarsController POST 'create' car car created success should create a car 
Failure/Error: lambda do 
    count should have been changed by 1, but was changed by 0 
# ./spec/controllers/car_controller_spec.rb:20 

2) CarsController POST 'create' car car created success should redirect to the user cars page 
Failure/Error: response.should redirect_to user_car_path(@user, @car) 
    Expected response to be a redirect to <http://test.host/users/115/cars/40> but was a redirect to <http://test.host/users/115/cars/new>. 
# ./spec/controllers/car_controller_spec.rb:27 

，但我的应用程序正常工作;这里是我的CarController

class CarsController < ApplicationController 
.... 

def create 
    @user = User.find(params[:user_id]) 
    @car = @user.cars.build(params[:car]) 
    if @car.save 
    redirect_to user_car_path(@user, @car), :flash => { :notice => " car created!" } 
    else 
    redirect_to new_user_car_path ,:flash => { :notice => " sorry try again :(" } 
    end 
end 
def show 
    @user = User.find(params[:user_id])  
    @car = @user.cars.find(params[:id]) 
end 

.... 

Answer 1

您正在数据库中创建汽车，而不是在before(:each)中创建汽车对象。你也通过参数:cars而不是:car。最后，我还亲自使用let。尝试这个。

describe "POST 'create' car" do 

    let(:user) { User.create!(:email => "foo@example.com", :password => "foobar", :password_confirmation => "foobar") } 
    let(:car) { Car.new(:brand => "example", :color => "foobar", :model => "foobar", :year =>"2012")} 

    it "should create a car" do 
    lambda do 
     post :create, :car => car, :user_id => user.id 
    end.should change(Car, :count).by(1) 
    end 

    it "should redirect to the user cars page" do 
    post :create, :cars => car, :user_id => user.id 
    # note: car doesn't have an ID, you have to fetch it from the db to get an id 
    response.should redirect_to user_car_path(user.id, user.cars.last.id) 
    end 
end 

最后一点，你会想看看Factory Girl

然后，你可以这样做，而不是：

let(:user){ FactoryGirl.create(:user) } 
let(:car) { FactoryGirl.build(:car) } # note: BUILD not CREATE 

Answer 2

我想你想以下（：车=>：汽车和使用PARAMS这将使控制器中的汽车产生有效的我感到困惑，为什么要创建在规范汽车。因为这似乎是汽车创作的测试）

it "should create a car" do 
    lambda do 
     post :create, :car => {:brand => "example", :color => "foobar", :model => "foobar", :year =>"2012"}, :user_id => @user.id 
    end.should change(Car, :count).by(1) 
    end 

    it "should redirect to the user cars page" do 
    post :create, :car => {:brand => "example", :color => "foobar", :model => "foobar", :year =>"2012"}, :user_id => @user.id 
    response.should redirect_to user_car_path(@user, @car) 
    end 

Answer 3

我认为这是因为您的验证失败。要知道，如果它不能做到这一点，之前保存在你的控制器：

puts @car.valid? 

如果是假的，你的测试将失败，这是正常的。要设置为true，你可以这样做：

before(:each) do 
    ... 
    Car.any_instance.stub(:valid?).and_return(true) 
end 

您还可以使用存根和嘲笑返回实例为User.find和Car.build。请参阅文档：https://www.relishapp.com/rspec/rspec-mocks/v/2-6/docs/method-stubs