Rails 3, RSpec 2.5: Using should_receive or stub_chain with named scopes
I use Rails 3.0.4 and RSpec 2.5. In my controllers I use named scopes heavily, for example
@collection = GuestbookEntry.nonreplies.bydate.inclusive.paginate( :page => params[:page], :conditions => { ... })
In my tests, I want to be able to mock the result of such a query, not the wording. I do not think it makes sense to do something like
GuestbookEntry.stub_chain(:nonreplies, :bydate, ...).and_return(...)
because this test will fail the moment I decide to reorder the named scopes.
With Rails 2.3 and RSpec 1.x, this worked fine: I could write
Guest开发者_JAVA技巧bookEntry.should_receive(:find).with(:all, :conditions => { ... })
and the above call would be caught and correctly handled. However, with Rails 3, for some reason this does not work any more.
Why? How do I set expectations or stubs on the result of nested scopes? Since everything in Rails 3's ActiveModel is a named scope (thanks to ARel), this must be possible somehow, or tests would indeed be very brittle.
Thanks!
Update: See also issue report on GitHub.
This problem has bugged me for a while too!
I believe the reason the behaviour is different from Rails 2 is because the query is no longer being performed during the variable assignment in the controller. Instead, it's lazy-loaded as required.
I agree with Mark Wilden that it's better to wrap all of these scopes in a larger scope and spec that in your model. This scope clearly has a specific function, so just as one would spec the behaviour of a method which calls several other methods, you would spec the behaviour of a scope that joins several other scopes.
I would wrap such a complicated query in its own scope, and stub that.
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