added more info to AccessDenied exception

lib/allowy.rb

@@ -5,7 +5,16 @@
 require "allowy/controller_extensions"
 
 module Allowy
-  class UndefinedActionError < StandardError; end
   class UndefinedAccessControlError < StandardError; end
-  class AccessDenied < StandardError; end
+  class UndefinedActionError < StandardError; end
+
+  class AccessDenied < StandardError
+    attr_reader :action, :subject
+
+    def initialize(message, action, subject)
+      @message = message
+      @action = action
+      @subject = subject
+    end
+  end
 end

lib/allowy/access_control.rb

@@ -21,7 +21,7 @@ def cannot?(*args)
       end
 
       def authorize!(*args)
-        raise AccessDenied unless can?(*args)
+        raise AccessDenied.new("Not authorized", args.first, args[1]) unless can?(*args)
       end
     end
 

spec/access_control_spec.rb

@@ -30,8 +30,13 @@ module Allowy
 
     describe "#authorize!" do
       it "shuold raise error" do
-        expect { subject.authorize! :read, 'deny' }.to raise_error AccessDenied
+        expect { subject.authorize! :read, 'deny' }.to raise_error AccessDenied do |err|
+          err.message.should_not be_blank
+          err.action.should == :read
+          err.subject.should == 'deny'
+        end
       end
+
       it "should not raise error" do
         expect { subject.authorize! :read, 'allow' }.not_to raise_error AccessDenied
       end