[rspec-users] Spec'ing via features

Tim Walker walketim at gmail.com
Tue Nov 25 14:40:42 EST 2008


Question: In Cucumber when you're writing code to satisfy steps and accessing
the model objects directly, what support for asserts, responses, etc.
do people use. (the equivalent of ActionController::TestCase and
ActiveSupport::TestCase), Fixtures, etc.

Thanks,

T

On Tue, Nov 25, 2008 at 12:16 PM, Matt Wynne <matt at mattwynne.net> wrote:
>
> On 25 Nov 2008, at 17:26, Ben Mabey wrote:
>
>> David Chelimsky wrote:
>>>
>>> On Tue, Nov 25, 2008 at 12:52 AM, Ben Mabey <ben at benmabey.com> wrote:
>>>
>>>> Andrew Premdas wrote:
>>>>
>>>>> I came across this idea of dropping unit tests for acceptance tests in
>>>>> the java world. It didn't like it there and I don't like it here, but
>>>>> maybe thats because I'm an old fuddy duddy or something :). I do think
>>>>> that every public method of an object should be specifically unit
>>>>> tested, and yes that means that if you refactor your object you should
>>>>> refactor your unit tests. This isn't really that much of a burden if
>>>>> you design your objects to have simple and minimal public api's in the
>>>>> first place.
>>>>>
>>>>>
>>>> +1
>>>>
>>>>> What is that makes you think you can refactor code run acceptance
>>>>> tests and be save without unit tests? Writing tests "that guarantee
>>>>> the correct functioning of the system" isn't something you can just
>>>>> do. Best you can hope for with acceptance tests is that part of the
>>>>> system functions correctly most of the time in some circumstances.
>>>>>
>>>>> Perhaps its the BDD ideal that your only writing the code you need to
>>>>> make your acceptance tests pass, that make you think your acceptance
>>>>> tests cover all your code. However just because you've written minimal
>>>>> code to make an acceptance test pass doesn't mean that you can't use
>>>>> this code in a multitude of different ways
>>>>>
>>>>> Do you really think that BDD created code is just some black box that
>>>>> you can tinker around with restructure and still be sure it works just
>>>>> because your black box tests still work?
>>>>>
>>>>> I just don't believe you can get the coverage you need for an
>>>>> application using acceptance testing / features alone. If you do
>>>>> actually write enough features to do this you'll end up doing much
>>>>> more work than writing unit tests combined with features.
>>>>>
>>>>>
>>>> +1 again.
>>>>
>>>>> All best
>>>>>
>>>>> Andrew
>>>>>
>>>>>
>>>> Here is how I look at the two sets of tests...
>>>>
>>>> Features at the application level (acceptance tests) instill more
>>>> confidence
>>>>
>>>
>>> CONFIDENCE!
>>>
>>> That and, as Kent Beck describes today, responsible software, are why
>>> we do testing at all.
>>>
>>>
>>>> in me about the correctness of the system's behavior. Object level code
>>>> examples (unit tests) instill more confidence in me about the design of
>>>> the
>>>> system.
>>>> With acceptance tests passing we have no guarantee about the state of
>>>> the
>>>> design.  Remember, TDD/BDD naturally produces easy to test objects and
>>>> by
>>>> skipping object level examples you run the risk of creating dependent
>>>> laden,
>>>> highly coupled objects that are hard to test.  (Just think, you can make
>>>> all
>>>> of your features, for a web app, pass by writing the app in PHP4 with no
>>>> objects at all :p .)
>>>>
>>>
>>> Which is not an inherently bad deal, if that's your comfort zone, and
>>> if that's the comfort zone of *everybody* on your team.
>>>
>>>
>>>> I also think that acceptance tests are too slow to be used in all
>>>> refactorings and they are not fine grained enough so you'll end up doing
>>>> more debugging than you would otherwise with good object level coverage.
>>>>  I
>>>> generally try to keep each individual unit test faster than a tenth of a
>>>> second, as suggested in 'Working Effectively With Legacy Code'.  What
>>>> results is an extremely fast suite that can be used to quickly do
>>>> refactorings.  I have experienced the pain of using just Cucumber
>>>> features
>>>> first hand-- finding bugs on this level is just not as fast object level
>>>> examples.  If you skip object level examples you are incurring a
>>>> technical
>>>> debt that you will feel down the road, IMO.
>>>>
>>>> Someone at the start of this thread had wondered what people had learned
>>>> when they went through this process of balancing FIT tests with unit
>>>> tests.
>>>>
>>>
>>> I can speak to this a bit. Maybe more than a bit.
>>>
>>> When I was working with .NET FitNesse and NUnit, we had very high
>>> levels of coverage in NUnit. Early on one project I told Micah Martin
>>> (who co-created FitNesse with Bob Martin) that I was concerned about
>>> the duplication between our FitNesse tests and NUnit tests and
>>> questioned the value of keeping it.
>>>
>>> Micah pointed out reasons that made absolute 100% perfect sense in the
>>> context of the project we were working on. The customers were
>>> encouraged to own the FitNesse tests. They were stored on a file
>>> system, backed up in zip files, while the NUnit tests were stored in
>>> subversion with the code. The FitNesse fixtures were stored with the
>>> application code, distant from the FitNesse tests.
>>>
>>> In order to foster confidence in the code amongst the developers,
>>> having a high level of coverage in NUnit made sense, in spite of the
>>> duplication with some of the FitNesse tests.
>>>
>>> That duplication, by the way, was only in terms of method calls at the
>>> highest levels of the system. When a FitNesse test made an API call,
>>> that message went all the way to the database and back.
>>>
>>> When an NUnit test made the same call, that message typically got no
>>> further than the object in the test, using stubs and mocks to keep it
>>> isolated.
>>>
>>> Now fast forward to our current discussion about Cucumber and RSpec.
>>> As things stand today, we tend to store .feature files right in the
>>> app alongside the step_definitions and the application code.
>>>
>>> The implications here are different from having a completely decoupled
>>> acceptance testing system. I'm not saying that abandoning RSpec or
>>> Test::Unit or whatever is the right thing to do. But I certainly feel
>>> less concerned about removing granular code examples, especially on
>>> rails/merb controllers and views, when I've got excellent coverage of
>>> them from Cucumber with Webrat. Thus far I have seen a case where I
>>> couldn't quickly understand a failure in a view or controller based on
>>> the feedback I get from Cucumber with Webrat.
>>>
>>> But this is mostly because that combination of tools does a very good
>>> job of pointing me to the right place. This is not always the case
>>> with high level examples. If you're considering relaxing a requirement
>>> for granular examples, you should really consider each case separately
>>> and include the level of granularity of feedback you're going to get
>>> from your toolset when you make that decision.
>>>
>>> Now this is how *I* see things.
>>>
>>> For anybody who is brand new to all this, my feeling is that whatever
>>> pain there is from duplication between the two levels of examples and
>>> having to change granular examples to refactor is eclipsed by the pain
>>> of debugging from high level examples.
>>>
>>> Also, as I alluded to earlier, every team is different. If you are
>>> working solo, the implications of taking risks by working
>>> predominantly at higher levels is different from when you are on a
>>> team. The point of testing is not to follow a specific process. The
>>> point is to instill confidence so you can continue to work without
>>> migraines, and deliver quality software.
>>>
>>> Cheers,
>>> David
>>>
>>
>> Thanks for sharing your experience and insight!  Having never used
>> FitNesse I didn't see that distinction at all. What you said makes a lot of
>> sense.
>> -Ben
>
> Amen to that. Thanks guys, it's been a fascinating and enlightening
> discussion.
>
> I am looking forward to the next chance I get to talk about this with
> someone (who's interested!) over a beer.
>
> I don't suppose any of you are going to XP Day, London, this year?
>
> cheers,
> Matt
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