FixtureScenariosBuilder
=======================
This plugin is an add-on to the FixtureScenarios plugin by Tom Preston-Werner.
FixtureScenarios is required for this plugin to work.
FixtureScenarios
  Info: https://code.google.com/p/fixture-scenarios/
  SVN : https://fixture-scenarios.googlecode.com/svn/trunk/fixture_scenarios
This plugin
  Info: https://errtheblog.com/post/7708
  SVN : svn://errtheblog.com/svn/plugins/fixture_scenarios_builder
  Bugs: https://err.lighthouseapp.com/projects/466-plugins/tickets/new
== The Setup
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?
== The Download
Using the +scenario+ method within <tt>scenarios.rb</tt> file,
FixtureScenariosBuilder can create your YAML fixture scenarios automatically
at run time from Ruby-created fixtures.
Create a <tt>scenarios.rb</tt> file and place it in the root "fixtures"
directory:
  [RAILS_ROOT]
  +-test/
    +-fixtures/
      +-scenarios.rb
Now build your scenarios in this file, wrapping scenarios in the 
+scenario+ method and providing it with the name of your scenario.  
A brief example of a complete <tt>scenarios.rb</tt> 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 (when our tests
are first run) the following:
  [RAILS_ROOT]
  +-test/
    +-fixtures/
      +-banned_users/
        +-users.yml
Our generated <tt>users.yml</tt> 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.  FixtureScenariosBuilder will try,
to an extent, to guess the name of your key.  If it can't figure it out,
keys will be the standard user_001, user_002, etc format.
Thanks to Paul Cantrell's handywork, custom key names are supported. Simply use the
+name+ method:
  scenario :foo do
    name "small_red_widget", Widget.create(:size => 'small', :color => 'red')
    name "big_blue_widget",  Widget.create(:size => 'big',   :color => 'blue')
  end
Another option is to 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
On subsequent test runs this YAML file will not be needlessly re-created.  YAML
files will only be re-generated when the <tt>scenarios.rb</tt> file is 
modified.
If you for some reason need to force your scenarios to rebuild, pass in the
REBUILD_FIXTURES environment variables:
  $ rake test:units REBUILD_FIXTURES=true
Scenarios can also be nested using the familiar Rake-style dependency declaration.
  scenario :users do
    %w( Tom Chris ).each do |user|
      User.create(:name => user)
    end
  end
  scenario :banned_users => :users do
    User.create(:name => 'Kevin', :banned => true)
  end
== Rake
FixtureScenariosBuilder comes with one Rake task, `db:scenario:build' -- use it to
attempt to build your scenarios on demand.
== Bugs!
Please report bugs here: https://err.lighthouseapp.com/projects/466-plugins/tickets
>> Chris Wanstrath
=> chris[at]ozmm[dot]org