On 5 Mar 2011, at 12:06, Hedge Hog wrote:
> On Fri, Mar 4, 2011 at 8:12 PM, Matt Wynne <[email protected]> wrote:
>>
>> On 4 Mar 2011, at 05:45, Hedge Hog wrote:
>>
>>> Hi,
>>> I'm struggling with something that seems to be simple, and I've not
>>> had any joy following the RSpec books suggestions (p. 187).
>>> I'd like to test that a method raises and error when a file is not found.
>>> I've tried adding this in my example just before I call my method, but
>>> it never seems to get invoked.
>>> Pathname.stub(:exist?).and_return(false)
>>
>> That's stubbing a class method.
>>
>> exist? is an instance method so you need to stub the specific instance of
>> pathname that's being used in your object-under-test, rather than the
>> Pathname class.
>>
>
> Is there a (clean) way to intercept this instance and add the
> stub/mock to it? What I see in the Rspec books suggests I'd have to
> force the Pathname instance to the surface, as some method argument.
> That feels all wrong - to have to change my method's interface just to
> test a behavior.
>
> Appreciate any experience, comments or suggestions people may have.
You could try something like this:
fake_pathname = double(Pathname, :exist? => false)
Pathname.stub(:new).and_return(fake_pathname)
This is basically The Ruby Way of doing dependency injection.
>
>>>
>>> The whole example:
>>>
>>> it "should raise an error if RVM's install root does not exist" do
>>> Pathname.stub(:exist?).and_return(false)
>>> lambda{ B3::Bdd::Helpers.rvm_path}.should
>>> raise_error(RuntimeError, "File not found:")
>>> end
>>>
>>> Appreciate any tips.
>>>
>>> --
>>> πόλλ' οἶδ ἀλώπηξ, ἀλλ' ἐχῖνος ἓν μέγα
>>> [The fox knows many things, but the hedgehog knows one big thing.]
>>> Archilochus, Greek poet (c. 680 BC – c. 645 BC)
>>> http://wiki.hedgehogshiatus.com
>>> _______________________________________________
>>> rspec-users mailing list
>>> [email protected]
>>> http://rubyforge.org/mailman/listinfo/rspec-users
>>
>> cheers,
>> Matt
>>
>> [email protected]
>> 07974 430184
>>
>> _______________________________________________
>> rspec-users mailing list
>> [email protected]
>> http://rubyforge.org/mailman/listinfo/rspec-users
>
>
>
> --
> πόλλ' οἶδ ἀλώπηξ, ἀλλ' ἐχῖνος ἓν μέγα
> [The fox knows many things, but the hedgehog knows one big thing.]
> Archilochus, Greek poet (c. 680 BC – c. 645 BC)
> http://wiki.hedgehogshiatus.com
> _______________________________________________
> rspec-users mailing list
> [email protected]
> http://rubyforge.org/mailman/listinfo/rspec-users
cheers,
Matt
[email protected]
07974 430184
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