shoulda-matchers

Official Documentation

Test::Unit- and RSpec-compatible one-liners that test common Rails functionality. These tests would otherwise be much longer, more complex, and error-prone.

Refer to the shoulda-context gem if you want to know more about using shoulda with Test::Unit.

ActiveRecord Matchers

Matchers to test associations:

describe Post do
  it { should belong_to(:user) }
  it { should have_many(:tags).through(:taggings) }
end

describe User do
  it { should have_many(:posts) }
end

ActiveModel Matchers

Matchers to test validations and mass assignments:

describe Post do
  it { should validate_uniqueness_of(:title) }
  it { should validate_uniqueness_of(:title).scoped_to(:user_id, :category_id) }
  it { should validate_presence_of(:body).with_message(/wtf/) }
  it { should validate_presence_of(:title) }
  it { should validate_numericality_of(:user_id) }
  it { should ensure_inclusion_of(:status).in_array(['draft', 'public']) }
end

describe User do
  it { should_not allow_value("blah").for(:email) }
  it { should allow_value("a@b.com").for(:email) }
  it { should ensure_inclusion_of(:age).in_range(1..100) }
  it { should_not allow_mass_assignment_of(:password) }
end

ActionController Matchers

Matchers to test common patterns:

describe PostsController, "#show" do
  it { should permit(:title, :body).for(:create) }

  context "for a fictional user" do
    before do
      get :show, :id => 1
    end

    it { should assign_to(:user) }
    it { should respond_with(:success) }
    it { should render_template(:show) }
    it { should_not set_the_flash }
  end
end

Independent Matchers

Matchers to test non-Rails-dependent code:

describe Human do
  it { should delegate_method(:work).to(:robot) }
end

Installation

In Rails 3 and Bundler, add the following to your Gemfile:

group :test do
  gem "shoulda-matchers"
end

# rspec-rails needs to be in the development group so that Rails generators
# work.
group :development, :test do
  gem "rspec"
  gem "rspec-rails"
end

Shoulda will automatically include matchers into the appropriate example groups.

Credits

Shoulda is maintained and funded by thoughtbot. Thank you to all the contributors.

batter/shoulda-matchers