Testing is a firmly ingrained part of the Ruby culture: you probably ran across Test::Unit not long after you first started writing Ruby code (though it wouldn't be surprising if you ignored it for a while). But it hasn't been a static part of Ruby - we've seen the simple availability of tests evolve into test-driven development (TDD) that in turn gave rise to behavior-driven development (BDD). Along the way, Ruby has spawned a variety of testing tools and frameworks. The latest, Aslak Hellesoy's Cucumber, is the latest addition to the RSpec family of tools.

Cucumber is designed to allow you to execute feature documentation written in plain text (often known as "stories"). I've been experimenting with it as a replacement for integration tests in Rails. With Cucumber, you can write tests that look like this:

Scenario: See all vendors
    Given I am logged in as a user in the administrator role
    And There are 3 vendors
    When I go to the manage vendors page
    Then I should see the first 3 vendor names

With Cucumber, that it an executable specification that you can discuss with the customer and then use to verify the correct behavior of tests. Behind the scenes, you make it work by writing "steps," which are regex matchers that execute Ruby code. Here's one of the steps for that scenario:

Given /there are (d+) vendors/i do |n|
  Vendor.transaction do
    Vendor.destroy_all
    n.to_i.times do |n|
      Factory.create(:vendor, :business_name => "Vendor #{n}")
    end
  end
end

Ideally, you'll do this all in true BDD fashion: write the Cucumber features first, watch them fail, implement code to make them pass (with lower-level tests written with RSpec or Test::Unit), and repeat.

Cucumber is under rapid development, but it's already a useful part of my testing toolbox. In addition to integrating with RSpec and Rails, it works with Merb, Sinatra, and the Webrat web-testing framework (as well as, of course, pure Ruby projects). It also has translations into 20 languages and the ability to run FIT-style tabular tests. If you're looking for a higher level of abstraction in your tests, it's definitely worth checking out.

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