Unit testing a polymorphic association with fixtures

问题

I'm getting this error message:

ERROR["test_profile_display", UsersProfileTest, 2.569931] test_profile_display#UsersProfileTest (2.57s)
NoMethodError:         NoMethodError: undefined method `posts' for nil:NilClass
        app/controllers/users_controller.rb:14:in `show'
        test/integration/users_profile_test.rb:22:in `block in <class:UsersProfileTest>'
    app/controllers/users_controller.rb:14:in `show'
    test/integration/users_profile_test.rb:22:in `block in <class:UsersProfileTest>'

It seems character in the UsersController in the line @posts = @user.character.posts.paginate(page: params[:page]) is nil. There is a polymorphic relationship between users and characters. I thought I'd used the correct syntax in fixtures to tell rails that the user Bazley has a fixture: In characters.yml:

character_bazley:
  sociable: bazley (user)

How do I convince rails that the user fixture does indeed have a character belonging to it?

test/integration/users_profile_test.rb:

require 'test_helper'

class UsersProfileTest < ActionDispatch::IntegrationTest
  include ApplicationHelper

  def setup
    @user = users(:bazley)
  end

  test "profile display" do
    log_in_as(@user)
    get user_path(@user)
    assert_template 'users/show'
    assert_select 'title', full_title(@user.name)
    assert_select 'h1', text: @user.name
    assert_select 'h1>img.gravatar'
    assert_match @user.character.posts.count.to_s, response.body
    assert_select 'div.pagination'
    @user.character.posts.paginate(page: 1).each do |post|
      assert_match post.content, response.body
    end
  end
end # UsersProfileTest

user.rb:

class User < ActiveRecord::Base

  attr_accessor :remember_token, :activation_token, :reset_token
  has_one  :character, as: :sociable, dependent: :destroy
  .
  .
end

character.rb:

class Character < ActiveRecord::Base

  belongs_to :sociable, polymorphic: true
  has_many   :posts, dependent: :destroy
  validates  :sociable_id, presence: true
end # Character

users.yml:

bazley:
  name: Bazley
  email: bazley@oxdorf.com
  callsign: bazley
  password_digest: <%= User.digest('password') %>
  admin: true
  activated: true
  activated_at: <%= Time.zone.now %>

characters.yml:

character_bazley:
  sociable: bazley (user)

In UsersController:

def show
  @user = User.find_by_callsign(params[:callsign])
  @posts = @user.character.posts.paginate(page: params[:page]) # the line causing the error
  @page_name = "user_page"
  redirect_to root_url and return unless @user.activated
end

回答1:

Change characters.yml to be

character_bazley:
  sociable: bazley (User)

instead of

character_bazley:
  sociable: bazley (user)

Note it is User and not user. The keyword used here User will tell that the sociable_type is of User class.

Ref:

http://ruby-journal.com/rails/define-fixtures-with-polymorphic-association/ http://api.rubyonrails.org/v3.2.8/classes/ActiveRecord/Fixtures.html#label-Polymorphic+belongs_to

来源：https://stackoverflow.com/questions/27744713/unit-testing-a-polymorphic-association-with-fixtures

标签

ruby-on-rails

fixtures