Rails - 测试夹具错误NoMethodError：nil的未定义方法`type'：NilClass

Question

I have a problem running tests that use fixtures with associations between models.

Here's the error I get, as soon as I run rake test :

ERROR["test_truth", SevenPortfolioTest, 0.005154775]
 test_truth#SevenPortfolioTest (0.01s)
NoMethodError:         NoMethodError: undefined method `type' for nil:NilClass


ERROR["test_should_destroy_item_video", SevenPortfolio::ItemVideosControllerTest, 0.008887804]
 test_should_destroy_item_video#SevenPortfolio::ItemVideosControllerTest (0.01s)
NoMethodError:         NoMethodError: undefined method `type' for nil:NilClass


ERROR["test_should_get_index", SevenPortfolio::ItemVideosControllerTest, 0.011364416]
 test_should_get_index#SevenPortfolio::ItemVideosControllerTest (0.01s)
NoMethodError:         NoMethodError: undefined method `type' for nil:NilClass


ERROR["test_should_create_item_video", SevenPortfolio::ItemVideosControllerTest, 0.014584266]
 test_should_create_item_video#SevenPortfolio::ItemVideosControllerTest (0.01s)
NoMethodError:         NoMethodError: undefined method `type' for nil:NilClass


ERROR["test_should_get_new", SevenPortfolio::ItemVideosControllerTest, 0.017282812]
 test_should_get_new#SevenPortfolio::ItemVideosControllerTest (0.02s)
NoMethodError:         NoMethodError: undefined method `type' for nil:NilClass


ERROR["test_should_update_item_video", SevenPortfolio::ItemVideosControllerTest, 0.019729858]
 test_should_update_item_video#SevenPortfolio::ItemVideosControllerTest (0.02s)
NoMethodError:         NoMethodError: undefined method `type' for nil:NilClass


ERROR["test_should_get_edit", SevenPortfolio::ItemVideosControllerTest, 0.022365633]
 test_should_get_edit#SevenPortfolio::ItemVideosControllerTest (0.02s)
NoMethodError:         NoMethodError: undefined method `type' for nil:NilClass


ERROR["test_should_destroy_item", SevenPortfolio::ItemsControllerTest, 0.025860205]
 test_should_destroy_item#SevenPortfolio::ItemsControllerTest (0.03s)
NoMethodError:         NoMethodError: undefined method `type' for nil:NilClass


ERROR["test_should_get_edit", SevenPortfolio::ItemsControllerTest, 0.030867796]
 test_should_get_edit#SevenPortfolio::ItemsControllerTest (0.03s)
NoMethodError:         NoMethodError: undefined method `type' for nil:NilClass


ERROR["test_should_show_item", SevenPortfolio::ItemsControllerTest, 0.036687105]
 test_should_show_item#SevenPortfolio::ItemsControllerTest (0.04s)
NoMethodError:         NoMethodError: undefined method `type' for nil:NilClass


ERROR["test_should_update_item", SevenPortfolio::ItemsControllerTest, 0.040130774]
 test_should_update_item#SevenPortfolio::ItemsControllerTest (0.04s)
NoMethodError:         NoMethodError: undefined method `type' for nil:NilClass


ERROR["test_should_create_item_with_video", SevenPortfolio::ItemsControllerTest, 0.042776553]
 test_should_create_item_with_video#SevenPortfolio::ItemsControllerTest (0.04s)
NoMethodError:         NoMethodError: undefined method `type' for nil:NilClass


ERROR["test_should_get_index", SevenPortfolio::ItemsControllerTest, 0.045301694]
 test_should_get_index#SevenPortfolio::ItemsControllerTest (0.05s)
NoMethodError:         NoMethodError: undefined method `type' for nil:NilClass


ERROR["test_should_get_new", SevenPortfolio::ItemsControllerTest, 0.048094189]
 test_should_get_new#SevenPortfolio::ItemsControllerTest (0.05s)
NoMethodError:         NoMethodError: undefined method `type' for nil:NilClass


ERROR["test_should_create_item_with_gallery", SevenPortfolio::ItemsControllerTest, 0.051019403]
 test_should_create_item_with_gallery#SevenPortfolio::ItemsControllerTest (0.05s)
NoMethodError:         NoMethodError: undefined method `type' for nil:NilClass

I'm testing a rails engine. Here's my fixtures:

# test/fixtures/seven_portfolio/items.yml
item_one:
  description: item one description
  finished_at: <%= 7.days.ago %>
  is_featured: true
  item_type: 0

item_two:
  description: item two description
  finished_at: <%= 6.days.ago %>
  is_featured: false
  item_type: 1


# test/fixtures/seven_gallery/galleries.yml
gallery_one:
  title: seven_gallery_gallery_one_title
  item: item_one

# test/fixtures/seven_gallery/photos.yml
photo_one:
  caption: photo_one_caption
  gallery: gallery_one

# test/fixtures/seven_portfolio/item_videos.yml
one:
  item: item_one

When, for example, I remove item: item_one and similar associations lines. The test works well.

-- EDIT

Here's the backtrace

Command failed with status (1): [ruby -I"lib:lib:test"  "/home/rafael/.rbenv/versions/2.2.0/lib/ruby/2.2.0/rake/rake_test_loader.rb" "test/**/*_test.rb" ]

/home/rafael/.rbenv/versions/2.2.0/lib/ruby/2.2.0/rake/testtask.rb:108:in `block (3 levels) in define'
/home/rafael/.rbenv/versions/2.2.0/lib/ruby/2.2.0/rake/file_utils.rb:57:in `call'
/home/rafael/.rbenv/versions/2.2.0/lib/ruby/2.2.0/rake/file_utils.rb:57:in `sh'
/home/rafael/.rbenv/versions/2.2.0/lib/ruby/2.2.0/rake/file_utils_ext.rb:37:in `sh'
/home/rafael/.rbenv/versions/2.2.0/lib/ruby/2.2.0/rake/file_utils.rb:96:in `ruby'
/home/rafael/.rbenv/versions/2.2.0/lib/ruby/2.2.0/rake/file_utils_ext.rb:37:in `ruby'
/home/rafael/.rbenv/versions/2.2.0/lib/ruby/2.2.0/rake/testtask.rb:104:in `block (2 levels) in define'
/home/rafael/.rbenv/versions/2.2.0/lib/ruby/2.2.0/rake/file_utils_ext.rb:58:in `verbose'
/home/rafael/.rbenv/versions/2.2.0/lib/ruby/2.2.0/rake/testtask.rb:100:in `block in define'
/home/rafael/.rbenv/versions/2.2.0/lib/ruby/2.2.0/rake/task.rb:240:in `call'
/home/rafael/.rbenv/versions/2.2.0/lib/ruby/2.2.0/rake/task.rb:240:in `block in execute'
/home/rafael/.rbenv/versions/2.2.0/lib/ruby/2.2.0/rake/task.rb:235:in `each'
/home/rafael/.rbenv/versions/2.2.0/lib/ruby/2.2.0/rake/task.rb:235:in `execute'
/home/rafael/.rbenv/versions/2.2.0/lib/ruby/2.2.0/rake/task.rb:179:in `block in invoke_with_call_chain'
/home/rafael/.rbenv/versions/2.2.0/lib/ruby/2.2.0/monitor.rb:211:in `mon_synchronize'
/home/rafael/.rbenv/versions/2.2.0/lib/ruby/2.2.0/rake/task.rb:172:in `invoke_with_call_chain'
/home/rafael/.rbenv/versions/2.2.0/lib/ruby/2.2.0/rake/task.rb:165:in `invoke'
/home/rafael/.rbenv/versions/2.2.0/lib/ruby/2.2.0/rake/application.rb:150:in `invoke_task'
/home/rafael/.rbenv/versions/2.2.0/lib/ruby/2.2.0/rake/application.rb:106:in `block (2 levels) in top_level'
/home/rafael/.rbenv/versions/2.2.0/lib/ruby/2.2.0/rake/application.rb:106:in `each'
/home/rafael/.rbenv/versions/2.2.0/lib/ruby/2.2.0/rake/application.rb:106:in `block in top_level'
/home/rafael/.rbenv/versions/2.2.0/lib/ruby/2.2.0/rake/application.rb:115:in `run_with_threads'
/home/rafael/.rbenv/versions/2.2.0/lib/ruby/2.2.0/rake/application.rb:100:in `top_level'
/home/rafael/.rbenv/versions/2.2.0/lib/ruby/2.2.0/rake/application.rb:78:in `block in run'
/home/rafael/.rbenv/versions/2.2.0/lib/ruby/2.2.0/rake/application.rb:176:in `standard_exception_handling'
/home/rafael/.rbenv/versions/2.2.0/lib/ruby/2.2.0/rake/application.rb:75:in `run'
/home/rafael/.rbenv/versions/2.2.0/bin/rake:33:in `<main>'

---

EDIT

Here's Item class:

module SevenPortfolio
  class Item < ActiveRecord::Base
    has_one :item_video, class_name:'SevenPortfolio::ItemVideo', foreign_key: "seven_portfolio_item_id"
    has_one :item_gallery, class_name: 'SevenGallery::Gallery', foreign_key: "seven_portfolio_item_id"
    accepts_nested_attributes_for :item_video, :item_gallery

    before_save :process_type

    def process_type
      self.build_item_video if self.item_type == 0
      self.build_item_gallery if self.item_type == 1
    end

    def type_content
      self.item_gallery if self.item_type == 0
      self.item_video if self.item_type == 1
    end
  end
end

And Gallery class:

class SevenGallery::Gallery < ActiveRecord::Base
  include SevenGallery::Concerns::Gallery
  belongs_to :item, :class_name => 'SevenPortfolio::Item'
end

---

EDIT Here's the schema.rb file:

ActiveRecord::Schema.define(version: 20150414145951) do

  create_table "seven_gallery_galleries", force: :cascade do |t|
    t.string   "title",                   limit: 255
    t.datetime "created_at",                          null: false
    t.datetime "updated_at",                          null: false
    t.integer  "seven_portfolio_item_id", limit: 4
  end

  add_index "seven_gallery_galleries", ["seven_portfolio_item_id"], name: "index_seven_gallery_galleries_on_seven_portfolio_item_id", using: :btree

  create_table "seven_gallery_photos", force: :cascade do |t|
    t.string   "caption",                  limit: 255
    t.string   "image",                    limit: 255
    t.integer  "seven_gallery_gallery_id", limit: 4
    t.datetime "created_at",                                             null: false
    t.datetime "updated_at",                                             null: false
    t.boolean  "is_new",                   limit: 1,     default: true
    t.boolean  "is_featured",              limit: 1,     default: false
    t.text     "description",              limit: 65535
    t.string   "alt",                      limit: 255
    t.integer  "position",                 limit: 4,     default: 0
  end

  add_index "seven_gallery_photos", ["seven_gallery_gallery_id"], name: "index_seven_gallery_photos_on_seven_gallery_gallery_id", using: :btree

  create_table "seven_portfolio_item_videos", force: :cascade do |t|
    t.string   "url",                     limit: 255
    t.text     "description",             limit: 65535
    t.string   "title",                   limit: 255
    t.integer  "seven_portfolio_item_id", limit: 4
    t.datetime "created_at",                            null: false
    t.datetime "updated_at",                            null: false
  end

  add_index "seven_portfolio_item_videos", ["seven_portfolio_item_id"], name: "index_seven_portfolio_item_videos_on_seven_portfolio_item_id", using: :btree

  create_table "seven_portfolio_items", force: :cascade do |t|
    t.datetime "created_at",                                null: false
    t.datetime "updated_at",                                null: false
    t.text     "description", limit: 65535
    t.date     "finished_at"
    t.boolean  "is_featured", limit: 1,     default: false
    t.integer  "item_type",   limit: 4,     default: 0
  end

  add_foreign_key "seven_gallery_galleries", "seven_portfolio_items", on_delete: :cascade
  add_foreign_key "seven_gallery_photos", "seven_gallery_galleries", on_delete: :cascade
  add_foreign_key "seven_portfolio_item_videos", "seven_portfolio_items", on_delete: :cascade
end

Answer 1

I've hit the same errors after migrating and rolling back a few times in my dev environment. It's something to do with the "_type" column.

The only thing that fixed it for me was a drop/create of the test database:

bundle exec rake db:reset RAILS_ENV=test

Be confident your schema.rb is in good shape before doing this.

Answer 2

This error happen when in you model you create a relationship that doesnt have a field in the db. Example:

class Contact < ActiveRecord::Base
 belongs_to account
end

But in your table contacts:

create_table "contacts", force: :cascade do |t|
    t.string   "fname"
    t.string   "lname"
    t.string   "title"
    t.string   "description"
    t.datetime "created_at",                 null: false
    t.datetime "updated_at",                 null: false
    t.boolean  "primary"
    t.integer  "contactable_id"
    t.integer  "contactable_type"
  end

See there's no account_id field.

In my case I forgot to update the model's belongs_to to be polymorphic:

class Contact < ActiveRecord::Base
  belongs_to :contactable, polymorphic: true
end

class Account < ActiveRecord::Base
  has_many :contacts, as: :contactable
end

Answer 3

Is this not a duplicate/similar problem to this issue?

Loading Rails Fixtures in a Specific Order when Testing

What could be happening is your fixtures are not being loaded in the correct order so when item is referenced it comes up as nil.

From the response of the other answer you can try

Here's how you fix your issue:

1. Log into Postgresql with your default superuser (mine is "postgres") Perform the following command:

2. ALTER ROLE yourtestdbuser WITH SUPERUSER;

3. Enjoy your properly working fixtures.

If you are using mysql it is probably similar issue.

Answer 4

TL;DR: People are landing on this question for different reasons. My problem/solution is described in 'Fixing the error'. I hope this extended explanation will help you learn why you're experiencing this cryptic error, and save you some time debugging it.

How to diagnose this issue

I had almost the same error when running my tests: NoMethodError: undefined method 'id' for nil:NilClass , or NoMethodError: undefined method 'each' for nil:NilClass . There were no line numbers to reference, and Lucas' answer of rebuilding would sometimes work and then would stop working; I'd later learn this is because of caching and loading order of fixture files.

Finding where the error is thrown

My error was with how my fixtures were setup. I found this by running my tests with a full backtrace described in this StackOverflow answer :

BACKTRACE=YES rake test test/controllers/document_submissions_controller_test.rb

This pointed to the gem files in ActiveSupport that were throwing the error. Here's my full log for a single test:

So it seems the error is in loading my fixtures, since the error is originating in active_record/fixtures.rb:758 (see highlighted line above). However, I have a large amount of fixtures in my app, I needed to narrow down which in particular was causing the problem.

Setting a break point

I opened the active_record/fixtures.rb:758 file in my code editor using the command below:

code /Users/mattmcinnis/.rvm/gems/ruby-2.3.0/gems/activerecord-4.2.0/lib/active_record/fixtures.rb

Note: I'm using VSCode with the code command, but any code editor will do.

On line 758 where the error occurs, I saw this code:

FixtureSet::File.open(file) do |fh|
  fh.each do |fixture_name, row|  # line 758
    fixtures[fixture_name] = ActiveRecord::Fixture.new(row, model_class)
  end 
end

..which I wrapped in a rescue block, and modified to:

FixtureSet::File.open(file) do |fh|
  begin
    fh.each do |fixture_name, row|
      fixtures[fixture_name] = ActiveRecord::Fixture.new(row, model_class)
    end
  rescue
    debugger
  end
end

NOTE: Be sure to revert any changes to this file when you're done!

Finding the problem file

I'm interested in which file, captured in the loop above in the variable fh , was causing the error. Running my test suite again I hit my breakpoint and found the filename that was causing the problem:

> (byebug) fh
  => ... @file="permissions.yml"

Fixing the error

In my permissions.yml file, my fixture is referring to a related model by hard coding the 'id' in, instead of referring by name:

Ex. permissions.yml

permission1:
  ...
  user_id: <%= User.first.id %>  # Bad!

Fixing the last line to something like, user: user1 to refer to the user1 fixture in users.yml solved the issue.

Hope this helps someone. I lost half a day on this one, and found it super hard to diagnose.