[rspec-users] Q: object.id is deprecated. How to mock?

s.ross cwdinfo at gmail.com
Tue Nov 25 14:04:25 EST 2008

In Rails, the primary key, by default 'id', is used all over the
place. However, Ruby now deprecates the use of constructs like:

@post = Post.find(:first)
@post_id = @post.id

I buy the rationale, as the Object#id is something of a reserved
method. However, changing all references to use [:id], while seemingly
the correct approach, also has the unwanted side-effect of breaking
every mock created using mock_model that references the id that way.

Sure, I can go in and stub [] to return self[:id] for each mock
object, but that ActiveRecord objects behave more as a hash than as an
object (IMO), so there are things like:


peppered throughout the codebase, and a big hammer like a stub of the
[]() method would also break specs. So the conundrum is how to make
mock_model respond only to the []() method with an argument of :id to
return self[:id].


1. Is there something bogus in my assumption that using @post[:id] is
preferred to @post.id?
2. Has anyone solved this problem and if so what worked?

BTW: I am aware that :to_param returns the id, but it seems counter-
intuitive to read code that takes advantage of this quirk.



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