Test not passing: undefined method `authenticate!' for nil:NilClass?

Question

I have the following failure:

Failures:

  1) RelationshipsController creating a relationship with Ajax should increment the Relationship count
     Failure/Error: xhr :post, :create, relationship: { followed_id: other_user.id }
     NoMethodError:
       undefined method `authenticate!' for nil:NilClass
     # ./spec/controllers/relationships_controller_spec.rb:14:in `block (4 levels) in <top (required)>'
     # ./spec/controllers/relationships_controller_spec.rb:13:in `block (3 levels) in <top (required)>'

But it is very strange, if I visit the site, the thing works (the followers counter does increment if I click the Follow button:

And the weirdest thing is that there isn't any authenticate! method in relationships_controller_spec.rb:

require 'spec_helper'

describe RelationshipsController do

  let(:user) { FactoryGirl.create(:user) }
  let(:other_user) { FactoryGirl.create(:user) }

  before { sign_in user }

  describe "creating a relationship with Ajax" do

    it "should increment the Relationship count" do
      expect do
        xhr :post, :create, relationship: { followed_id: other_user.id }
      end.to change(Relationship, :count).by(1)
    end

    it "should respond with success" do
      xhr :post, :create, relationship: { followed_id: other_user.id }
      response.should be_success
    end
  end

  describe "destroying a relationship with Ajax" do

    before { user.follow!(other_user) }
    let(:relationship) { user.relationships.find_by_followed_id(other_user) }

    it "should decrement the Relationship count" do
      expect do
        xhr :delete, :destroy, id: relationship.id
      end.to change(Relationship, :count).by(-1)
    end

    it "should respond with success" do
      xhr :delete, :destroy, id: relationship.id
      response.should be_success
    end
  end
end

Neither in the controller:

class RelationshipsController < ApplicationController
  before_filter :authenticate_user!

  def create
    @user = User.find(params[:relationship][:followed_id])
    current_user.follow!(@user)
    respond_to do |format|
      format.html { redirect_to @user }
      format.js
    end
  end

  def destroy
    @user = Relationship.find(params[:id]).followed
    current_user.unfollow!(@user)
    respond_to do |format|
      format.html { redirect_to @user }
      format.js
    end
  end
end

What could be the problem?

(By the way, these test were made following the Ruby on Rails Tutorial. After that, I removed all the authentication system because I wanted to use Devise.)

Answer 1

I had to add this:

spec_helpers.rb:

RSpec.configure do |config|
  config.include Devise::TestHelpers, :type => :controller
end

Answer 2

Setting config.include Devise::TestHelpers, :type => :controller no longer works in later versions of Devise. What you need to do is log out an anonymous user to set up the proper variables:

before :each do
  sign_out :user
end