Added tests for calling the failure and success callbacks

This uncovered some bug not firering the event_failed callback
in any case of an exception has been raised. This is now handled.

The exception is just re-raised if the record doesn't have defined
a event_failed callback. If he had it is up to the implementation
to handle the execption. We are just return false.

lib/transitions/machine.rb

@@ -45,22 +45,28 @@ def update(options = {}, &block)
 
     def fire_event(event, record, persist, *args)
       state_index[record.current_state(@name)].call_action(:exit, record)
-      if new_state = @events[event].fire(record, nil, *args)
-        state_index[new_state].call_action(:enter, record)
-
-        if record.respond_to?(event_fired_callback)
-          record.send(event_fired_callback, record.current_state, new_state, event)
+      begin
+        if new_state = @events[event].fire(record, nil, *args)
+          state_index[new_state].call_action(:enter, record)
+
+          if record.respond_to?(event_fired_callback)
+            record.send(event_fired_callback, record.current_state, new_state, event)
+          end
+
+          record.current_state(@name, new_state, persist)
+          @events[event].success.call(record) if @events[event].success
+          return true
+        else
+          record.send(event_fired_callback, event) if record.respond_to?(event_failed_callback)
+          return false
         end
-
-        record.current_state(@name, new_state, persist);
-        @events[event].success.call(record) if @events[event].success
-        true
-      else
+      rescue => e
         if record.respond_to?(event_failed_callback)
           record.send(event_failed_callback, event)
+          return false
+        else
+          raise e
         end
-
-        false
       end
     end
 

test/test_state_transition_success_callback.rb

@@ -0,0 +1,60 @@
+require 'helper'
+
+class DrivingInstructor
+  def self.applause!
+  end
+end
+
+class DrivingSchoolCar
+  include Transitions
+
+  state_machine do
+    state :parked
+    state :running
+    state :driving
+    state :switched_off
+
+    event :start_driving, :success => lambda { |car| DrivingInstructor.applause! } do
+      transitions :from => :parked, :to => :driving, :on_transition => [:start_engine, :loosen_handbrake, :push_gas_pedal]
+    end
+
+    event :switch_off_engine do
+      transitions :from => :parked, :to => :switched_off
+    end
+  end
+
+  %w!start_engine loosen_handbrake push_gas_pedal!.each do |m|
+    define_method(m){}
+  end
+end
+
+class TestStateTransitionSuccessCallback < Test::Unit::TestCase
+  def setup
+    @car = DrivingSchoolCar.new
+  end
+
+  test "should execute the success callback after successfull event execution" do
+    DrivingInstructor.expects(:applause!)
+
+    @car.start_driving!
+  end
+
+  test "should not execute the success callback after event execution failed" do
+    DrivingInstructor.expects(:applause!).never
+
+    @car.stubs(:event_failed)
+    @car.expects(:loosen_handbrake).raises("Drive with handbrake fail!")
+    @car.start_driving!
+  end
+
+  test "should execute the event_failed_callback and don't raise error if callback is defined" do
+    @car.start_driving
+    @car.expects(:event_failed).with(:switch_off_engine)
+    @car.switch_off_engine
+  end
+
+  test "should just re-raise any error on transition if the event_failed_callback isn't defined" do
+    @car.start_driving
+    assert_raise(Transitions::InvalidTransition) { @car.switch_off_engine }
+  end
+end