"NoMethodError: undefined method `admin?' for nil:NilClass" - Test Error - ruby-on-rails

Question

I am currently in the process of learning Ruby on Rails through Michael Hartl's Rails Tutorial (Chapter 12). I am suddenly getting the below error.
UsersControllerTest#test_should_redirect_destroy_when_not_logged_in:
NoMethodError: undefined method admin?' for nil:NilClass
app/controllers/users_controller.rb:92:inadmin_user'
test/controllers/users_controller_test.rb:48:in block (2 levels) in <class:UsersControllerTest>'
test/controllers/users_controller_test.rb:47:inblock in '
Here is my test code:
test "should redirect destroy when not logged in" do
assert_no_difference 'User.count' do
delete :destroy, id: #user
end
assert_redirected_to login_url
end
And the rest of my code:
class UsersController < ApplicationController
before_action :correct_user, only: [:edit, :update]
before_action :admin_user, only: :destroy
before_action :logged_in_user, only: [:index, :edit, :update, :destroy,
:following, :followers]
def destroy
User.find(params[:id]).destroy
flash[:success] = "User deleted"
redirect_to users_url
end
def index
#users = User.paginate(page: params[:page])
end
def show
#user = User.find(params[:id])
#microposts = #user.microposts.paginate(page: params[:page])
end
def new
#user = User.new
end
def create
#user = User.new(user_params)
if #user.save
#user.send_activation_email
flash[:info] = "Please check your email to activate your account."
redirect_to root_url
else
render 'new'
end
end
def edit
#user = User.find(params[:id])
end
def update
#user = User.find(params[:id])
if #user.update_attributes(user_params)
flash[:success] = "Profile updated"
redirect_to #user
else
render 'edit'
end
end
def following
#title = "Following"
#user = User.find(params[:id])
#users = #user.following.paginate(page: params[:page])
render 'show_follow'
end
def followers
#title = "Followers"
#user = User.find(params[:id])
#users = #user.followers.paginate(page: params[:page])
render 'show_follow'
end
private
def user_params
params.require(:user).permit(:name, :email, :password,
:password_confirmation)
end
# Before filters
# Confirms a logged-in user.
def logged_in_user
unless logged_in?
store_location
flash[:danger] = "Please log in."
redirect_to login_url
end
end
# Confirms the correct user.
def correct_user
#user = User.find(params[:id])
redirect_to(root_url) unless current_user?(#user)
end
# Confirms an admin user.
def admin_user
redirect_to(root_url) unless current_user.admin?
end
end
Can someone please have a look and tell me where I am going wrong? The code has basically been copied from the tutorial so I'm at a loss.
Thanks.

Answer 1

I had this same error in the Hartl tutorial. The problem was a missed :destroy action in listing 9.53 in users_controller.rb. Tests were back to green once I found that missing bit.
That said, it would be great if someone could explain precisely why this is the case.
The correct code:
before_action :logged_in_user, only: [:index, :edit, :update, :destroy]

Answer 2

Change admin_user method like this:-
def admin_user
redirect_to(root_url) unless current_user.present? && current_user.admin?
end
This will check first that current_user is present or not then check second condition(current_user.admin?). If current_user.present? will false then it will not check second condition.

Answer 3

You need to update your admin_user method to check if user is even logged in.
# Confirms an admin user.
def admin_user
redirect_to(root_url) if current_user.nil? || !current_user.admin?
end