don't allow updating a closed case, fixed #10

lib/desk_api/action/update.rb

@@ -2,9 +2,14 @@ module DeskApi
   module Action
     module Update
       def update(params = {})
+        if kind_of?(resource('case')) and status == 'closed'
+          raise DeskApi::Error::NotUpdateable
+        end
+
         params.each_pair do |key, value|
           send("#{key}=", value) if respond_to?("#{key}=")
         end
+
         setup(client.patch(@_links.self.href, @_changed).body)
       end
     end

lib/desk_api/error/not_updateable.rb

@@ -0,0 +1,10 @@
+require 'desk_api/error'
+
+module DeskApi
+  class Error
+    # Raised when an updateable resources becomes non-updateable
+    # and you try to update it
+    class NotUpdateable < DeskApi::Error
+    end
+  end
+end