RSpec undefined method "errors_on"

Question

I have the following model that I want to test with RSpec:

class Language < ActiveRecord::Base
  has_and_belongs_to_many :dvds
  validates :title, presence: true, uniqueness: { case_sensitive: false }
end

language_spec.rb

describe Language do
  describe 'title validation' do
    context 'title is present' do
      before(:each) do
        @lang = Language.new(title: 'English')
      end

      it 'is valid with present title' do
        expect(@lang).to have_exactly(0).errors_on(:title)
      end
    end

    context 'title is not present' do
      before(:each) do
        @lang = Language.create
      end

      it 'has an error on title attribute' do
        expect(@lang).to have_exactly(1).errors_on(:title)
      end

    end
  end
end

Unfortunately I'm getting test failures:

Failures:

1) Language title validation title is present is valid with present title Failure/Error: expect(@lang).to have_exactly(0).errors_on(:title) NoMethodError: undefined method errors_on' for #<Language:0xaa40e98> # ./spec/models/language_spec.rb:9:inblock (4 levels) in '

2) Language title validation title is not present has an error on title attribute Failure/Error: expect(@lang).to have_exactly(1).errors_on(:title) NoMethodError: undefined method errors_on' for #<Language id: nil, title: nil, created_at: nil, updated_at: nil> # ./spec/models/language_spec.rb:19:inblock (4 levels) in '

Gemfile

source 'https://rubygems.org'

# Bundle edge Rails instead: gem 'rails', github: 'rails/rails'
gem 'rails', '4.1.1'
# Use sqlite3 as the database for Active Record
gem 'sqlite3'
# Use SCSS for stylesheets
gem 'sass-rails', '~> 4.0.3'
# Use Uglifier as compressor for JavaScript assets
gem 'uglifier', '>= 1.3.0'
# Use CoffeeScript for .js.coffee assets and views
gem 'coffee-rails', '~> 4.0.0'
# See https://github.com/sstephenson/execjs#readme for more supported runtimes
# gem 'therubyracer',  platforms: :ruby

# Use jquery as the JavaScript library
gem 'jquery-rails'
# Turbolinks makes following links in your web application faster. Read more: https://github.com/rails/turbolinks
gem 'turbolinks'
# Build JSON APIs with ease. Read more: https://github.com/rails/jbuilder
gem 'jbuilder', '~> 2.0'
# bundle exec rake doc:rails generates the API under doc/api.
gem 'sdoc', '~> 0.4.0',          group: :doc

# Spring speeds up development by keeping your application running in the background. Read more: https://github.com/rails/spring
gem 'spring',        group: :development

# Pagination plugin
gem 'will_paginate', '~> 3.0'

# Testing
group :development, :test do
  gem "rspec-rails", "~> 3.0.1"
  gem "factory_girl_rails", "~> 4.4.1"
end

group :test do
  gem "faker", "~> 1.3.0"
  gem "capybara", "~> 2.3.0"
  gem "database_cleaner", "~> 1.3.0"
  gem "launchy", "~> 2.4.2"
  gem "selenium-webdriver", "~> 2.42.0"
end

Any ideas why I'm getting undefined method "errors_on"?

Answer 1

The errors_on matcher moved to the rspec-collection_matchers gem, so adding that to your Gemfile would fix the error.

If you wanted to move away from non-core syntax, you could do

describe Language do
  describe 'title validation' do
    context 'title is present' do
      before(:each) do
        @lang = Language.new(title: 'English')
      end

      it 'is valid with present title' do
        expect(@lang.errors[:title]).to be_empty
      end
    end

    context 'title is not present' do
      before(:each) do
        @lang = Language.create
      end

      it 'has an error on title attribute' do
        expect(@lang.errors.added?(:title, :blank)).to be_true
      end
    end

  end
end

(have_exactly and related matchers have also moved to rspec-collection_matchers.)