RSpec: It Should Behave Like
I was going through an older project of ours and cleaning up some specs and noticed how often we were doing the same thing in several places. When we started the project, we didn’t get the benefits of shared groups. Now that we have some time to go through and update some of our older specs, I’ve been trying to take advantage of the features currently available in RSpec. One feature that I haven’t seen a lot of mention of by people is shared groups, so I thought I’d take a few minutes to write up a quick intro to using it.
To pick some low-hanging fruit, let’s take an all-too-familiar method,
which you might be familiar with… login_required. Sound familiar?
Have you found yourself stubbing login_required over and over
throughout your specs?
describe Admin::DohickiesController, ‘index’ do
before( :each ) do
controller.stub!( :login_required )
Dohicky.should_receive( :paginate ).and_return( Array.new )
get :index
end
…
end\
If you’re requiring that a user should be logged in when interacting
with most of the application (as in the case of an administration
section/namespace), you might want to consolidate some of your work into
one shared specification group. The basic premise behind this is that
you can write a typical describe block and load it into any other spec
groups that you need. For example, in our case, we’ll need to stub
login_required in several places. We can set this up in one shared
group and reference it wherever necessary.
For example, here is what we’ll start off with.
describe “an admin user is signed in” do
before( :each ) do
controller.stub!( :login_required )
end
end
describe Admin::DohickiesController, ‘index’ do
…\
However, the new describe block isn’t accessible from the block at the
bottom of the example… yet. To do this, we just need to pass the
option: :shared => true as you’ll see in the following example.
describe “an admin user is signed in”, :shared => true doruby\
`before( :each ) doruby\
controller.stub!( :login_required )ruby\
`endruby
end``ruby\
Great, now we can reference it by referring to it with:
it_should_behave_like SharedGroupName. In our example above, this
would look like:
describe “an admin user is signed in” do
before( :each ) do
controller.stub!( :login_required )
end
end
describe Admin::DohickiesController, ‘index’ do
it_should_behave_like “an admin user is signed in”
before( :each ) do
Dohicky.should_receive( :paginate ).and_return( Array.new )
get :index
end
…
end
describe Admin::DohickiesController, ‘new’ do
it_should_behave_like “an admin user is signed in”
before( :each ) do
dohicky = mock_model( Dohicky ) Dohicky.should_receive( :new ).and_return( dohicky
)
get :new
end
…\
That’s it! Pretty simple, eh? We can now reference this shared group in
any describe blocks that we want to. A benefit to this approach is that
we can make change the authentication system (say, we decide to switch
it entirely and/or even just change method names, set any other
prerequisites necessary when an admin is signed in), we’ll have a single
place to change in our specs. (tip: you can put these in your
spec_helper file)
You can learn more about it_should_behave_like and other helpful
features on the RSpec documentation
site.
If you have any suggestions on better ways of handling things like this, please follow up and share your solutions. I’m always looking to sharpen my tools. :-)
Update
In response, Bryan Helmkamp suggests that a
better solution is to define a method in our specs like, for example:
build_mock_user_and_login. then calling it in our before(:each). So,
maybe the approach above isn’t the most ideal method but I did wantt o
draw some attention to it_should_behave_like. I suppose that I need a
better example.. another post, perhaps? :-)
Also, Ed Spencer has posted an article titled, DRYing up your CRUD
controller
RSpecs,
which will introduce you mor to it_should_behave_like.
Thanks for feedback people!
Related Posts
- [Be Careful that you don’t Stub your Big
Toe](http://www.robbyonrails.com/articles/2007/02/13/be-careful-that-you-dont-stub-your-big-toe)
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