mocha developer - Aug 2007 - mock framework ethics question

Hi James, Jim, and everyone else who''s listening.

I''ve been investigating an interesting bug related to mocks and rails
AssociationProxies. See
http://rubyforge.org/tracker/?func=detail&atid=3149&aid=12547&group_id=797
for details.

The crux is that if you do this (rspec mock syntax):

  obj.should_receive(:msg).with(mock_of_a_model)

and the implementation does this:

  obj.msg(containing_model.association_proxy)

the expectation fails. This is because the comparison that rspec mocks make is:

  expected == actual

which, in this case ends up being:

  mock_of_a_model == association_proxy

As it turns out, mocha and flexmock do this the same way, which means
that this will fail in any of the three frameworks.

So here''s the mock-ethics question of the week:

Should the comparison be changed to:

  actual == expected

or

  actual == expected || expected == actual

or ... neither?

I have arguments for all three - I''d like to hear your thoughts.

Cheers,
David

Hi David,

This is probably too late for you, but I''m inclined towards the third
"neither" option. This is because I prefer to stub the association
method
itself which means I can use a standard mock for the model rather than an
rspec mock_model or whatever you call it.

Cheers, James.

On 22/08/2007, David Chelimsky <dchelimsky at gmail.com>
wrote:
>
> Hi James, Jim, and everyone else who''s listening.
>
> I''ve been investigating an interesting bug related to mocks and
rails
> AssociationProxies. See
>
http://rubyforge.org/tracker/?func=detail&atid=3149&aid=12547&group_id=797
> for details.
>
> The crux is that if you do this (rspec mock syntax):
>
>   obj.should_receive(:msg).with(mock_of_a_model)
>
> and the implementation does this:
>
>   obj.msg(containing_model.association_proxy)
>
> the expectation fails. This is because the comparison that rspec mocks
> make is:
>
>   expected == actual
>
> which, in this case ends up being:
>
>   mock_of_a_model == association_proxy
>
> As it turns out, mocha and flexmock do this the same way, which means
> that this will fail in any of the three frameworks.
>
> So here''s the mock-ethics question of the week:
>
> Should the comparison be changed to:
>
>   actual == expected
>
> or
>
>   actual == expected || expected == actual
>
> or ... neither?
>
> I have arguments for all three - I''d like to hear your thoughts.
>
> Cheers,
> David
> _______________________________________________
> mocha-developer mailing list
> mocha-developer at rubyforge.org
> http://rubyforge.org/mailman/listinfo/mocha-developer
>


-- 
James.
http://blog.floehopper.org
http://tumble.floehopper.org