stubbing delegates

Question

I stubbed the subset billed? method
subset.stub(:billed?).and_return(true)

line_item has a delegate for billed? to subset billed?

when I call the methods the following occurs

(rdb:1) subset.billed?  
true  
(rdb:1) subset.line_items[0].billed?  
false  
(rdb:1) subset === subset.line_items[0].order_subset  
true  
(rdb:1) subset.billed? == subset.line_items[0].subset.billed?  
false  

on the first call it works
on the second I call the billed method over the relation delegated and the stub failes
on the third I check if the subset and the subest of the line_item-relation are the same model and its true
on the fourth I compare the output of the same method called directly on the subset and indirectly over the relation and it fails

is there anybody ever had this?

Answer 1

subset and subset.line_items[0].order_subset are indeed different objects. === with two objects ends up using the following logic:

http://github.com/rails/rails/blob/master/activerecord/lib/active_record/base.rb#L1906-1910

To see what I mean, run this:

subset.object_id == subset.line_items[0].order_subset.object_id

You'll see that you get false.

This is somewhat of a problem with activerecord. When you have reverse associations, rather than referring to the model you've already loaded, it loads an entirely new copy of the record.