[rspec-users] [BDD] View specs and cucumber -- duplication of effort?
ben at benmabey.com
Wed Oct 28 23:19:49 EDT 2009
> Hi Guys
> I'm going to put the cat amongst the pigeons here in the hope of some
> clarity falling out of the sky on me.
> My question is this: In a world with Cucumber what is the value of
> view specs?
> In the community (railscamp, for example) there are a fair number of
> people using Cucumber and skipping view specs, but still speccing
> controllers, models, tricky view helpers and so on.
> Why? Because they don't find them helpful. Indeed they are seen as a
> waste of time (money) not only duplicating Cucumber coverage, but also
> introducing a high-maintenance example group which designers (who
> don't run tests) will frequently break.
> These people aren't stupid. They're producing working apps. I don't
> claim that their work cycle is perfect: this is about utility and
> efficiency, or about being lazy or avoiding boredom, if you prefer.
> I've been working in a mixed environment, with an existing project
> which uses rspec and cucumber (sans view specs) and my own green field
> app for a different client.
> I've been following the BDD approach prescribed by the RSpec book (or
> so I think). This works, and has produced a lot of LOC.
> I've not worried, as it has given me plenty of practice with the
> various arms of rspec, webrat, and other tools.
> Now that I'm more comfortable with them things are starting to get
> tiresome, especially duplication, and I'm worried I'm creating a
> monolith. Too many specs => TLDR ?
> What should I try using view specs for? Why are they better than
> cucumber for this?
> "Driving views through examples helps us think about what the view
> needs in order for it to do its job. It encourages us to write the
> code we wish we had to fulfil those needs."
> I'm not sure how this is any different to what I do in the outer
> circle with Cucumber. If I write an explicit scenario like
> http://gist.github.com/221004 then I already know what the view needs
> to let me do.
> If I write something more broad-brush (which you will do, if quickly
> sketching out features during a design meeting) like "When I add a
> page link" I have to then define that step so it goes red (or, heaven
> forbid, green). But to write that step definition I have to know how I
> can interact with the page. This example actually comes from a broad-
> brush step being expanded in the scenario itself rather than hiding it
> away in a step definition, but that's a different subject.
> I'm specifying the page's behaviour in the scenario, or in the step
> definition. Why duplicate this process with a view spec?
> I keep coming back to the introduction of chapter 23 in the RSpec book
> but don't seem to be getting anywhere from it.
> For the time being I'm going to keep writing view specs, but try to
> make them lighter and cut some of the dead wood by describing unusual
> or interesting behaviour rather than all behaviour.
> I'd love to hear your thoughts.
View specs can be useful but they can also be very brittle and add undue
maintenance to a project. The brittleness, which causes a lot of
maintenance headaches, usually is caused by specing the design and
structure too closely. If the designer changes the layout this
shouldn't break the view specs IMO. I think a good strategy is to avoid
this is by keeping things very general (as much as you can). For
example, you should only verify if the correct text was displayed
instead of focusing on the HTML structure. Verifying that certain
elements are present via their ids but not tag type or css class which
are subject to change by the designer will also help reduce brittleness.
I'm also of the opinion that view specs *only* make sense on large
complicated views. An example of such a page would be a users profile
page on a social network site. A lot of stuff is generally displayed on
a page like that. Setting up all the data required to test that via
Cucumber can be very expensive/slow and cucumbersome. (Especially
considering that such a page will contain random data and be
personalized to the person viewing the profile.) Being able to isolate
all of that complexity and test it individually with view specs (and
probably with a Presenter and corresponding spec) will make your life a
lot easier and actually save you time and from maintenance headaches.
For simple pages that are already being exercised via Cucumber view
specs are overkill IMO. A simple form submission and checking the
presence of some basic text is well within the bounds of what Cucumber
should be testing. If you are finding you want to write "Then I should
see.. And I should see.. And I should see., etc" that is an indication
that a view spec *may* be helpful in that situation.
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