[rspec-users] Test for a gem/plugin?

[Matt Wynne]

On 9 Dec 2008, at 19:06, James Byrne wrote:

> I have decided that for now I am going to use the authlogic gem to
> provide authentication for the project I am creating.  The question
> arises, since authentication is a user feature request and since it is
> to be satisfied through the use of a gem (not a plugin) then should  
> one
> test for the availability of the gem or not?
>
> Secondly, given that a gem is providing the authentication logic  
> (and is
> not my code which therefore should not be tested by me) then what  
> should
> one test for with respect to the specific implementation?  The  
> existence
> of particular attributes?  The existence of a users model?
>
> Does one write step definitions (assuming rspec) like:
>
> When /users are authenticated/ do
>  #TODO: This does not work even when the model class exists.
>  User.should exist
> end
>
> When /authentication by authlogic/ do
>  #TODO: Find out how to test for a loaded gem within an application
> end

If you're working at the level of Cucumber features, I would stay well  
away from implementation details like the particular technology you're  
using for authentication.

Remember this is called Behaviour Driven Development[1] for a reason.  
You're focussing on specifying the desired *behaviour* of the system.  
How you chose to satisfy the user's need for that behaviour is an  
entirely separate matter.

A large benefit of having Acceptance Tests, IMO, is that you could  
radically change your implementation under the hood, such as switching  
to a different authentication mechanism, and the features would still  
be valid. You might have to code up some of your steps a little  
differently, but as long as the users want the same thing from the  
system, the features should not have to change in the slightest.

[1]http://dannorth.net/introducing-bdd

Matt Wynne
http://blog.mattwynne.net
http://www.songkick.com