Allow factory_girl_rails to auto configure factory girl as the fixture replacement mechanism.

Gemfile.lock

@@ -1,7 +1,7 @@
 PATH
   remote: .
   specs:
-    factory_girl_rails (1.1.0)
+    factory_girl_rails (1.2.0)
       factory_girl (~> 2.1.0)
       railties (>= 3.0.0)
 

features/fixture_replacement_config.feature

@@ -0,0 +1,31 @@
+@disable-bundler
+Feature:
+  In order to not have to manually configure factory girl as the testing fixture replacement
+  by using the --fixture-replacement=factory_girl option
+  as a Rails3 and Factory Girl user
+  I would like the Factory Girl Rails gem to configure Factory Girl
+  as the fixture replacement.
+
+  Background:
+    Given I successfully run `bundle exec rails new testapp`
+    And I cd to "testapp"
+    And I add "factory_girl_rails" from this project as a dependency
+
+  Scenario: Using Factory Girl and Factory Girl Rails with Test Unit generates
+  a factory file and does not generate a fixture file
+    And I successfully run `bundle install`
+    And I successfully run `bundle exec rails generate model User name:string`
+    Then the following files should exist:
+      | test/factories/users.rb |
+    And the following files should not exist:
+      | test/fixtures/users.yml |
+
+
+  Scenario: Using Factory Girl and Factory Girl Rails with RSpec should generate a factory file
+    And I add "rspec-rails" as a dependency
+    And I successfully run `bundle install`
+    And I successfully run `bundle exec rails generate model User name:string`
+    Then the following files should exist:
+      | spec/factories/users.rb |
+    And the following files should not exist:
+      | spec/fixtures/users.yml |

features/step_definitions/rails_steps.rb

@@ -1,3 +1,7 @@
 When /^I add "([^"]+)" from this project as a dependency$/ do |gem_name|
-  append_to_file('Gemfile', %{gem "#{gem_name}", :path => "#{PROJECT_ROOT}"})
+  append_to_file('Gemfile', %{gem "#{gem_name}", :path => "#{PROJECT_ROOT}"\n})
+end
+
+When /^I add "([^"]+)" as a dependency$/ do |gem_name|
+  append_to_file('Gemfile', %{gem "#{gem_name}"\n})
 end

lib/factory_girl_rails/railtie.rb

@@ -3,11 +3,22 @@ require 'rails'
 
 module FactoryGirl
   class Railtie < Rails::Railtie
+
+    initializer "factory_girl.set_fixture_replacement" do
+      generators = config.respond_to?(:app_generators) ? config.app_generators : config.generators
+
+      if generators.options[:rails][:test_framework] == :rspec
+        generators.fixture_replacement :factory_girl, :dir => 'spec/factories'
+      else
+        generators.test_framework :test_unit, :fixture => false, :fixture_replacement => :factory_girl
+      end
+    end
+
     config.after_initialize do
       FactoryGirl.definition_file_paths = [
-        File.join(Rails.root, 'factories'),
-        File.join(Rails.root, 'test', 'factories'),
-        File.join(Rails.root, 'spec', 'factories')
+          File.join(Rails.root, 'factories'),
+          File.join(Rails.root, 'test', 'factories'),
+          File.join(Rails.root, 'spec', 'factories')
       ]
       FactoryGirl.find_definitions
     end