[rspec-users] features and form filling - going declarative?

Matt Wynne matt at mattwynne.net
Fri Nov 7 09:54:53 EST 2008


On 7 Nov 2008, at 06:09, Andrew Premdas wrote:
> I'm working on writing features for a wizard. The wizard collects  
> information from a number of different forms, and you can navigate  
> through it in a number of ways. Anyhow one of these forms is a  
> customer form collecting name, and email.
>
> In the context of the wizard I feel that the following scenarios
>
>   Scenario:
>     Given I step to customer
>        And I fill in my customer details correctly
>
>   Scenario:
>     Given I step to customer
>        And I fill in my customer details incorrectly
>      Then I should see an error
>
> are preferable to
>
>   Scenario:
>     Given I step to customer
>        And I fill in email with fred at example.com
>        And I fill in name "Fred Bloggs"
>
>     Given I step to customer
>        And I fill in email with ''
>        And I fill in name "Fred Bloggs"
>      Then I should see an error
>
>     # add table for different combinations of form fields that cause  
> errors
>     # consider checking that errors are appropriate
>
>
> note:  Given I step to customer is nested step doing all sorts to  
> get to the form
>
> What do you think?

Good questions! You're getting into some pretty subtle stuff here, and  
it's hard to even articulate what I think about it as it's changing  
all the time as I get more experience working with cucumber.

I guess as Joseph has said, you want to balance out keeping the noise  
down in the feature without hiding away important information about  
the desired behaviour.

One technique is to have a single noisy 'declarative' scenario that  
explicitly walks around filling things in, then all the rest use more  
'imperative' style steps where most of the detail is buried away. I  
think, and I know that this sounds wishy-washy, you need to try out  
both and see how they feel to you.

In the example you gave, I where the specification seems be be about  
valid email addresses, I would probably make my step something like  
this:

     Given I step to the customer stage of the wizard
     When I fill in a valid name
     And I fill out an email address "blah"
     Then I should see an error

Thereby hiding the irrelevant "Fred Bloggs", but surfacing the  
important "blah"

> I'm looking for some input on this, and in particular am wondering  
> where should I put the more specific tests for form validation,  
> error messages etc. in my test hierarchy, or even if I should test  
> them at all (could you argue they're in built rails functionality).

Hmm....

Again, this is getting from science to art. I think you need the  
features to tell you whether the whole things hangs together (e.g. can  
the form display a validation message at all?), but when you start to  
iterate more tightly with specific examples of a valid / invalid  
object, I that's where I would drop into unit tests and write code  
examples against the model object (or whatever you use for validation).

Having said that, I'm putting more and more specification into  
cucumber features - the more steps you write, the more you build up a  
re-usable language for describing your system, the easier it gets.

Make any sense? Does that help at all?

cheers
Matt

http://blog.mattwynne.net



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