From c68759174915be3da91ce438eb2b8237b7f36c8c Mon Sep 17 00:00:00 2001
From: Eric Lindvall <eric@5stops.com>
Date: Wed, 9 Jul 2008 16:17:35 -0700
Subject: [PATCH] Provide explanation for why a transition cannot be made.

---
 lib/event.rb | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/event.rb b/lib/event.rb
index 2e943efe..e4f89810 100644
--- a/lib/event.rb
+++ b/lib/event.rb
@@ -14,7 +14,7 @@ def initialize(name, options = {}, &block)
 
       def fire(obj, to_state=nil, *args)
         transitions = @transitions.select { |t| t.from == obj.aasm_current_state }
-        raise AASM::InvalidTransition if transitions.size == 0
+        raise AASM::InvalidTransition, "Event '#{name}' cannot transition from '#{obj.aasm_current_state}'" if transitions.size == 0
 
         next_state = nil
         transitions.each do |transition|