Testing named_scope

Testing RSpec
1

Hi! I’m new to rspec and was wondering how named_scopes are usually
tested? Is it enough to test that it’s defined? or do you need to test
the behavior as well? I’ve been reading around and this seems to be
the tester’s choice, i just want to get people’s opinion on this :smiley:

2

On Sun, Jan 17, 2010 at 8:17 PM, Nin [email protected] wrote:

Hi! I’m new to rspec and was wondering how named_scopes are usually
tested? Is it enough to test that it’s defined? or do you need to test
the behavior as well? I’ve been reading around and this seems to be
the tester’s choice, i just want to get people’s opinion on this :smiley:

Specify the behaviour, don’t test the implementation. The fact that
a
method is defined with a named_scope declaration is irrelevant to the
behaviour.

One reason for this is keeping things decoupled. Consider the fact that
named_scope just changed to scope today [1]. If your specs specify a
call to
named_scope, they’ll have to change, whereas if they they only specify
the
name you define then you’ll only need to update the implementation when
you
upgrade.

[1]

That all make sense?

3

class User < ActiveRecord::Base
named_scope :admins, :conditions => {:admin => true}
end

describe User, “admins” do
it “should include users with admin flag” do
admin = User.create! :admin => true
User.admin.should include(admin)
end

it “should not include users without admin flag” do
admin = User.create! :admin => false
User.admin.should_not include(admin)
end
end

4

On Mon, Jan 18, 2010 at 4:01 AM, Pat M. [email protected]
wrote:

describe User, “admins” do
it “should include users with admin flag” do
admin = User.create! :admin => true
User.admin.should include(admin)
end

it “should not include users without admin flag” do
admin = User.create! :admin => false
User.admin.should_not include(admin)
end
end

Small style matter, but I’ve leaning towards more declarative sounding
example names:

describe User, “.admins” do
it “includes users with admin flag” do
admin = User.create! :admin => true
User.admin.should include(admin)
end

it “excludes users without admin flag” do
non_admin = User.create! :admin => false
User.admin.should_not include(non_admin)
end
end

class User < ActiveRecord::Base
named_scope :admins, :conditions => {:admin => true}
end

We still have ‘should’ in the examples, but this produces more
‘spec-like’ output:

User.admins
includes users with admin flag
excludes users without admin flag

FWIW,
David

5

On Sun, Jan 17, 2010 at 9:17 PM, Nin [email protected] wrote:

Hi! I’m new to rspec and was wondering how named_scopes are usually
tested? Is it enough to test that it’s defined? or do you need to test
the behavior as well? I’ve been reading around and this seems to be
the tester’s choice, i just want to get people’s opinion on this :smiley:

While this is focused on shoulda, I still found it helpful for
demonstrating how to properly deal with testing named_scopes.

Best regards,
Michael G.

6

David C. wrote:

named_scope :admins, :conditions => {:admin => true}
User.admin.should_not include(admin)
User.admin.should include(admin)
end

Another small style matter… I like using the :: notation for class
methods as that is what the documentation tools tend to use (RDoc and
Yard):

describe User, “::admins” do
…
…
end

On the topic of RSpec as a form of documentation has anyone used the
yard-doc rspec plugin? It appears to be pretty limited ATM but seems
very cool with a lot of potential. Just like Ioke’s docs it embeds the
specs as part of the documentation with the option to view the source.
Here is the example from the projects home page:

http://lsegal.github.com/yard-spec-plugin/String.html#pig_latin-instance_method

-Ben

7

On Mon, Jan 18, 2010 at 5:17 AM, David C.
[email protected]wrote:

On Mon, Jan 18, 2010 at 4:01 AM, Pat M. [email protected]
wrote:

…

it “should not include users without admin flag” do
admin = User.create! :admin => true
named_scope :admins, :conditions => {:admin => true}
end

We still have ‘should’ in the examples, but this produces more
‘spec-like’ output:

User.admins
includes users with admin flag
excludes users without admin flag

I agree, David. I’ve been omitting “should” from the beginning. For me,
it
made the start of every example look too similar.

Regards,
Craig

8

Nin wrote:

Hi! I’m new to rspec and was wondering how named_scopes are usually
tested? Is it enough to test that it’s defined? or do you need to test
the behavior as well? I’ve been reading around and this seems to be
the tester’s choice, i just want to get people’s opinion on this :smiley:

Here is my approach:
http://gusiev.com/2010/07/bdd-rspec-matcher-to-test-named_scope-scoped-rails-3/
It is a little advanced. Hopefully you will get the idea.