The shoulda gem is a meta gem with two dependencies:

• shoulda-context
• shoulda-matchers

Official documentation for each gem:

• shoulda-context
• shoulda-matchers

The following describes different use cases and combinations.

This is what thoughtbot currently does. We write tests like:

describe Post do
  it { should belong_to(:user) }
  it { should validate_presence_of(:title) }
end

The belong_to and validate_presence_of methods are the matchers. All matchers are Rails 3-specific.

Add rspec-rails and shoulda-matchers to the project's Gemfile:

group :test do
  gem 'rspec-rails'
  gem 'shoulda-matchers'
end

For the folks who prefer Test::Unit, they'd write tests like:

class UserTest < Test::Unit::TestCase
  should have_many(:posts)
  should_not allow_value("blah").for(:email)
end

The have_many and allow_value methods are the same kind of matchers seen in the RSpec example. They come from the shoulda-matchers gem.

Add shoulda to the project's Gemfile:

group :test do
  gem 'shoulda'
end

If you're not testing a Rails project or don't want to use the matchers, you can use shoulda-context independently to write tests like:

class CalculatorTest < Test::Unit::TestCase
  context "a calculator" do
    setup do
      @calculator = Calculator.new
    end

    should "add two numbers for the sum" do
      assert_equal 4, @calculator.sum(2, 2)
    end

    should "multiply two numbers for the product" do
      assert_equal 10, @calculator.product(2, 5)
    end
  end
end

Add shoulda-context to the project's Gemfile:

group :test do
  gem 'shoulda-context'
end

Shoulda is maintained and funded by thoughtbot, inc

Thank you to all the contributors!

The names and logos for thoughtbot are trademarks of thoughtbot, inc.

Shoulda is Copyright © 2006-2011 Tammer Saleh, thoughtbot. It is free software, and may be redistributed under the terms specified in the MIT-LICENSE file.