NestedScenarios

This plugin is based on FixtureScenarios and FixtureScenarioBuilder. It includes both worlds in just one plugin with some fixes, new features and Rails 2.2 support.

You can check them at:

FixtureScenarios
  Info: http://code.google.com/p/fixture-scenarios/
  SVN : http://fixture-scenarios.googlecode.com/svn/trunk/fixture_scenarios

FixtureScenariosBuilder
  Info: http://errtheblog.com/post/7708
  SVN : svn://errtheblog.com/svn/plugins/fixture_scenarios_builder

NestedScenarios
  Info: http://josevalim.blogspot.com/
  Git : http://github.com/josevalim/nested_scenarios

Install

Install NestedScenarios is very easy. It is stored in GitHub, so if you have never installed a gem via GitHub run the following:

gem sources -a http://gems.github.com

Then install the gem:

sudo gem install josevalim-nested_scenarios

In RAILS_ROOT/config/environment.rb:

config.gem "josevalim-nested_scenarios",  :lib => "nested_scenarios", :source => "http://gems.github.com"

Why

You may, from time to time, wish to build your fixtures entirely in Ruby. Doing so has its advantages, such as automatically created join tables and default attributes. YAML files, however, bring with them some real nice features in Rails which are difficult to abandon: transactional fixtures, table_name(:key) helpers, and auto-clearing between tests. How does one get the best of both worlds?

Usage

Using the scenario method within scenarios.rb file, FixtureScenariosBuilder can create your YAML fixture scenarios automatically at run time from Ruby-created fixtures.

Any file inside the fixture_path called scenarios.rb is loaded to generating scenarios:

[RAILS_ROOT]
+-test/
  +-fixtures/
    +-scenarios.rb

Or:

[RAILS_ROOT]
+-spec/
  +-fixtures/
    +-models/
      +-scenarios.rb
    +-controllers/
      +-scenarios.rb
    +-helpers/
      +-scenarios.rb

Now build your scenarios in those file, wrapping scenarios in the scenario method and providing it with the name of your scenario.

A brief example of a complete scenarios.rb file:

scenario :banned_users do
  %w( Tom Chris Kevin ).each_with_index do |user, index|
    User.create(:name => user, :banned => index.odd?)
  end
end

Assuming banned is a boolean field, this will create for us:

[RAILS_ROOT]
+-test/
  +-fixtures/
    +-banned_users/
      +-users.yml

Our generated users.yml file will look something like this:

chris: 
  name: Chris
  id: "2"
  banned: "1"
  updated_at: 2007-05-09 09:08:04
  created_at: 2007-05-09 09:08:04
kevin: 
  name: Kevin
  id: "3"
  banned: "0"
  updated_at: 2007-05-09 09:08:04
  created_at: 2007-05-09 09:08:04
tom: 
  name: Tom
  id: "1"
  banned: "0"
  updated_at: 2007-05-09 09:08:04
  created_at: 2007-05-09 09:08:04

Notice how the keys correspond to the user names. You can register fields that can be used as fixtures names by:

NestedScenarios.record_name_fields << :nickname

You can assign your records to instance variables, then call names_from_ivars at the conclusion of your scenario block.

scenario :foo do
  @small_red_widget = Widget.create(:size => 'small', :color => 'red')
  @big_blue_widget  = Widget.create(:size => 'big',   :color => 'blue')

  names_from_ivars!
end

The above produces the following YAML:

small_red_widget:
  size: small
  color: red
  updated_at: 2007-12-27 10:09:05
  created_at: 2007-12-27 10:09:05
big_blue_widget:
  size: big
  color: blue
  updated_at: 2007-12-27 10:19:23
  created_at: 2007-12-27 10:19:23

To build the scenario you have to run:

rake db:build:scenario

In NestedScenarios, scenarios are not generated automatically. Another change is how scenarios are nested:

scenario :models => { :users => :banned } do
  User.create(:name => 'Kevin', :banned => true)
end

This will create an YAML in the following dir:

[RAILS_ROOT]
+-test/
  +-fixtures/
    +-models/
      +-users/
        +-banned/
          +-users.yml

Finally, you can choose which scenario to use in your tests by:

scenario :users

Or, in the case of nested scenarios:

scenario :models => { :users => :banned }

If no scenario is sent, the default behaviour is adopted.