Question

I testing my app for create a new user car, later that the user creates the new car the app must redirect to the user_car_path (I post my routes):

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

so I’m testing my app with this rspec:

describe "POST 'create' car" do

describe "car created success" do
  before(:each) do
            @user = User.create!(:email => "[e-mail]", :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

but i got 2 errors

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

but my app works normally; here is my 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

You are creating the car in the database, rather than just creating a car object in the before(:each). Also you’re passing the param as :cars rather than :car. Finally, I’d also personally use let. Try this.

describe "POST 'create' car" do

  let(:user) { User.create!(:email => "[e-mail]", :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

As a final note, you will want to look into Factory Girl

Then you could do this instead:

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