Using OpenStruct as mock for ActiveRecord

As you may have noticed OpenStruct#id always returns the object id of the OpenStruct instance, even when you set id.

>> o = OpenStruct.new :id => 2
=> #<OpenStruct id=2>
>> o.id
(irb):4: warning: Object#id will be deprecated; use Object#object_id
=> 9850940

Fortunately there is a simple way around this.

OpenStruct.__send__(:define_method, :id) { @table[:id] }

Now OpenStruct behaves like we want.

>> o.id
=> 2

Note that hash and object_id still work fine. You probably want to keep in mind that we’ve redefined the default OpenStruct behaviour and it might cause problems elsewhere.