Fix locale for ActiveRecord getting added to the i18n load path multi…

…ple times

CHANGELOG.rdoc

@@ -1,5 +1,6 @@
 == master
 
+* Fix locale for ActiveRecord getting added to the i18n load path multiple times [Reiner Dieterich]
 * Fix callbacks, guards, and state-driven behaviors not always working on tainted classes [Brandon Dimcheff]
 * Use Ruby 1.9's built-in Object#instance_exec for bound callbacks when it's available
 * Improve performance of cached dynamic state lookups by 25%

lib/state_machine/integrations/active_record.rb

@@ -274,7 +274,11 @@ def self.matches?(klass)
       # Loads additional files specific to ActiveRecord
       def self.extended(base) #:nodoc:
         require 'state_machine/integrations/active_record/observer'
-        I18n.load_path << "#{File.dirname(__FILE__)}/active_record/locale.rb" if Object.const_defined?(:I18n)
+
+        if Object.const_defined?(:I18n)
+          locale = "#{File.dirname(__FILE__)}/active_record/locale.rb"
+          I18n.load_path << locale unless I18n.load_path.include?(locale)
+        end
       end
 
       # Adds a validation error to the given object 

test/unit/integrations/active_record_test.rb

@@ -965,16 +965,25 @@ def test_should_invalidate_using_customized_i18n_key_if_specified
           machine.invalidate(record, :state, :invalid_transition, [[:event, :ignite]])
           assert_equal 'cannot ignite', record.errors.on(:state)
         end
-      end
-
-      def test_should_invalidate_using_customized_i18n_string_if_specified
-        machine = StateMachine::Machine.new(@model, :messages => {:invalid_transition => 'cannot {{event}}'})
-        machine.state :parked, :idling
 
-        record = @model.new(:state => 'idling')
+        def test_should_invalidate_using_customized_i18n_string_if_specified
+          machine = StateMachine::Machine.new(@model, :messages => {:invalid_transition => 'cannot {{event}}'})
+          machine.state :parked, :idling
+
+          record = @model.new(:state => 'idling')
+
+          machine.invalidate(record, :state, :invalid_transition, [[:event, :ignite]])
+          assert_equal 'cannot ignite', record.errors.on(:state)
+        end
 
-        machine.invalidate(record, :state, :invalid_transition, [[:event, :ignite]])
-        assert_equal 'cannot ignite', record.errors.on(:state)
+        def test_should_only_add_locale_once_in_load_path
+          assert_equal 1, I18n.load_path.select {|path| path =~ %r{state_machine/integrations/active_record/locale\.rb$}}.length
+
+          # Create another ActiveRecord model that will triger the i18n feature
+          new_model
+
+          assert_equal 1, I18n.load_path.select {|path| path =~ %r{state_machine/integrations/active_record/locale\.rb$}}.length
+        end
       end
     else
       $stderr.puts 'Skipping ActiveRecord I18n tests. `gem install active_record` >= v2.2.0 and try again.'