Add i18n support for ActiveRecord validation errors

CHANGELOG.rdoc

@@ -1,5 +1,6 @@
 == master
 
+* Add i18n support for ActiveRecord validation errors
 * Add a validation error when failing to transition for ActiveRecord / DataMapper / Sequel integrations
 
 == 0.6.0 / 2009-03-03

README.rdoc

@@ -46,6 +46,7 @@ Some brief, high-level features include:
 * State values of any data type
 * Dynamically-generated state values
 * Inheritance
+* Internationalization
 * GraphViz visualization creator
 
 Examples of the usage patterns for some of the above features are shown below.
@@ -446,3 +447,4 @@ dependencies are listed below.
 * ActiveRecord[http://rubyonrails.org] integration: 2.1.0 or later
 * DataMapper[http://datamapper.org] integration: 0.9.0 or later
 * Sequel[http://sequel.rubyforge.org] integration: 2.8.0 or later
+* i18n[http://github.com/svenfuchs/i18n] support (when used outside of ActiveRecord): 0.1.1 or later

lib/state_machine/integrations/active_record.rb

@@ -187,12 +187,21 @@ 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)
       end
 
       # Adds a validation error to the given object after failing to fire a
       # specific event
       def invalidate(object, event)
-        object.errors.add(attribute, invalid_message(object, event))
+        if Object.const_defined?(:I18n)
+          object.errors.add(attribute, :invalid_transition,
+            :event => event.name,
+            :value => state_for(object).name,
+            :default => @invalid_message
+          )
+        else
+          object.errors.add(attribute, invalid_message(object, event))
+        end
       end
 
       # Resets an errors previously added when invalidating the given object

lib/state_machine/integrations/active_record/locale.rb

@@ -0,0 +1,9 @@
+{:en => {
+  :activerecord => {
+    :errors => {
+      :messages => {
+        :invalid_transition => StateMachine::Machine.default_invalid_message % ['{{event}}', '{{value}}']
+      }
+    }
+  }
+}}

lib/state_machine/machine.rb

@@ -260,7 +260,7 @@ def initialize(owner_class, *args, &block)
       @states = StateCollection.new
       @callbacks = {:before => [], :after => []}
       @namespace = options[:namespace]
-      @invalid_message = options[:invalid_message] || self.class.default_invalid_message
+      @invalid_message = options[:invalid_message]
       self.owner_class = owner_class
       self.initial_state = options[:initial]
 
@@ -1102,7 +1102,7 @@ def add_states(new_states)
       # Generates the message to use when invalidating the given object after
       # failing to transition on a specific event
       def invalid_message(object, event)
-        @invalid_message % [event.name, state_for(object).name]
+        (@invalid_message || self.class.default_invalid_message) % [event.name, state_for(object).name]
       end
   end
 end

test/unit/integrations/active_record_test.rb

@@ -161,6 +161,8 @@ def test_should_not_rollback_transaction_if_true
       end
 
       def test_should_invalidate_using_errors
+        I18n.backend = I18n::Backend::Simple.new if Object.const_defined?(:I18n)
+
         record = @model.new
         record.state = 'parked'
 
@@ -737,6 +739,74 @@ def test_should_invoke_callbacks_in_specific_order
         assert_equal expected, @notifications
       end
     end
+
+    if Object.const_defined?(:I18n)
+      class MachineWithInternationalizationTest < ActiveRecord::TestCase
+        def setup
+          I18n.backend = I18n::Backend::Simple.new
+
+          # Initialize the backend
+          I18n.backend.translate(:en, 'activerecord.errors.messages.invalid_transition', :event => 'ignite', :value => 'idling')
+
+          @model = new_model
+        end
+
+        def test_should_invalidate_using_i18n_default
+          I18n.backend.store_translations(:en, {
+            :activerecord => {
+              :errors => {
+                :messages => {
+                  :invalid_transition => 'cannot {{event}} when {{value}}'
+                }
+              }
+            }
+          })
+
+          machine = StateMachine::Machine.new(@model)
+          machine.state :parked, :idling
+          event = StateMachine::Event.new(machine, :ignite)
+
+          record = @model.new(:state => 'idling')
+
+          machine.invalidate(record, event)
+          assert_equal 'cannot ignite when idling', record.errors.on(:state)
+        end
+
+        def test_should_invalidate_using_customized_i18n_key_if_specified
+          I18n.backend.store_translations(:en, {
+            :activerecord => {
+              :errors => {
+                :messages => {
+                  :bad_transition => 'cannot {{event}} when {{value}}'
+                }
+              }
+            }
+          })
+
+          machine = StateMachine::Machine.new(@model, :invalid_message => :bad_transition)
+          machine.state :parked, :idling
+          event = StateMachine::Event.new(machine, :ignite)
+
+          record = @model.new(:state => 'idling')
+
+          machine.invalidate(record, event)
+          assert_equal 'cannot ignite when idling', record.errors.on(:state)
+        end
+      end
+
+      def test_should_invalidate_using_customized_i18n_string_if_specified
+        machine = StateMachine::Machine.new(@model, :invalid_message => 'cannot {{event}} when {{value}}')
+        machine.state :parked, :idling
+        event = StateMachine::Event.new(machine, :ignite)
+
+        record = @model.new(:state => 'idling')
+
+        machine.invalidate(record, event)
+        assert_equal 'cannot ignite when idling', record.errors.on(:state)
+      end
+    else
+      $stderr.puts 'Skipping ActiveRecord I18n tests. `gem install active_record` and try again.'
+    end
   end
 rescue LoadError
   $stderr.puts 'Skipping ActiveRecord tests. `gem install active_record` and try again.'