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Pat Maddox

2007-Jan-01 09:05 UTC

[rspec-users] Another "how do I spec this?"

I wanted to add a convenience method on my User class to see if he was
already signed up for a tournament.  Here''s my spec

context "A User signed up for one tournament" do
  setup do
    @t1 = Tournament.new
    @t1.save false
    @t2 = Tournament.new
    @t2.save false
    @user = User.new
    @user.save false
    @user.registrations << Registration.new(:tournament => @t1)
  end

  specify "should be signed up for that tournament" do
    @user.should_be_signed_up_for @t1
  end

  specify "should not be signed up for another tournament" do
    @user.should_not_be_signed_up_for @t2
  end
end

class User < ActiveRecord::Base
  has_many :registrations

  def signed_up_for?(tournament)
    !registrations.find_by_tournament_id(tournament).nil?
  end
end

Are there any potential improvements, or is that the best way to spec it?

Pat

David Chelimsky

2007-Jan-01 14:16 UTC

head link

[rspec-users] Another "how do I spec this?"

On 1/1/07, Pat Maddox <pergesu at gmail.com>
wrote:> I wanted to add a convenience method on my User class to see if he was
> already signed up for a tournament.  Here''s my spec
>
> context "A User signed up for one tournament" do
>   setup do
>     @t1 = Tournament.new
>     @t1.save false
>     @t2 = Tournament.new
>     @t2.save false
>     @user = User.new
>     @user.save false
>     @user.registrations << Registration.new(:tournament => @t1)
>   end
>
>   specify "should be signed up for that tournament" do
>     @user.should_be_signed_up_for @t1
>   end
>
>   specify "should not be signed up for another tournament" do
>     @user.should_not_be_signed_up_for @t2
>   end
> end
>
> class User < ActiveRecord::Base
>   has_many :registrations
>
>   def signed_up_for?(tournament)
>     !registrations.find_by_tournament_id(tournament).nil?
>   end
> end
>
> Are there any potential improvements, or is that the best way to spec it?
Couple of thoughts. Creating new unvalidated models seems to be
something useful, so...

module ModelSpecUtils
  def unvalidated_model(klass)
    model = klass.new
    model.save(false)
    model
  end
end

Also, this line:

@user.registrations << Registration.new(:tournament => @t1)

is breaking encapsulation a bit. Given that and the utility module
above, I might end up w/ something like this:

context "A User signed up for one tournament" do
  include ModelSpecUtils

  setup do
    @tournament1 = unvalidated_model(Tournament)
    @tournament2 = unvalidated_model(Tournament)
    @user = unvalidated_model(User)
    @user.register_for(@tournament1)
  end

  specify "should be signed up for that tournament" do
    @user.should_be_signed_up_for @tournament1
  end

  specify "should not be signed up for another tournament" do
    @user.should_not_be_signed_up_for @tournament2
  end
end

David
>
> Pat
> _______________________________________________
> rspec-users mailing list
> rspec-users at rubyforge.org
> http://rubyforge.org/mailman/listinfo/rspec-users
>

Pat Maddox

2007-Jan-05 04:47 UTC

head link

[rspec-users] Another "how do I spec this?"

On 1/1/07, David Chelimsky <dchelimsky at gmail.com>
wrote:> On 1/1/07, Pat Maddox <pergesu at gmail.com> wrote:
> > I wanted to add a convenience method on my User class to see if he was
> > already signed up for a tournament.  Here''s my spec
> >
> > context "A User signed up for one tournament" do
> >   setup do
> >     @t1 = Tournament.new
> >     @t1.save false
> >     @t2 = Tournament.new
> >     @t2.save false
> >     @user = User.new
> >     @user.save false
> >     @user.registrations << Registration.new(:tournament =>
@t1)
> >   end
> >
> >   specify "should be signed up for that tournament" do
> >     @user.should_be_signed_up_for @t1
> >   end
> >
> >   specify "should not be signed up for another tournament"
do
> >     @user.should_not_be_signed_up_for @t2
> >   end
> > end
> >
> > class User < ActiveRecord::Base
> >   has_many :registrations
> >
> >   def signed_up_for?(tournament)
> >     !registrations.find_by_tournament_id(tournament).nil?
> >   end
> > end
> >
> > Are there any potential improvements, or is that the best way to spec
it?
>
> Couple of thoughts. Creating new unvalidated models seems to be
> something useful, so...
>
> module ModelSpecUtils
>   def unvalidated_model(klass)
>     model = klass.new
>     model.save(false)
>     model
>   end
> end
>
> Also, this line:
>
> @user.registrations << Registration.new(:tournament => @t1)
>
> is breaking encapsulation a bit. Given that and the utility module
> above, I might end up w/ something like this:
>
> context "A User signed up for one tournament" do
>   include ModelSpecUtils
>
>   setup do
>     @tournament1 = unvalidated_model(Tournament)
>     @tournament2 = unvalidated_model(Tournament)
>     @user = unvalidated_model(User)
>     @user.register_for(@tournament1)
>   end
>
>   specify "should be signed up for that tournament" do
>     @user.should_be_signed_up_for @tournament1
>   end
>
>   specify "should not be signed up for another tournament" do
>     @user.should_not_be_signed_up_for @tournament2
>   end
> end
>
> David
My original spec is bad, because it doesn''t show how the Registration
model is being used.  Right now in my controller I''m just doing
@registration = Registration.new :tournament => @tournament, :user =>
current_user

and then saving it.  It''s probably not good then that I''m
doing
user.registrations<< in the spec.  I know that breaks encapsulation,
but I''m not doing it in my app.  Either way though the specs should
match the use.

This brings up a more interesting question (to me at least.  It could
be pointless to some).  I''ve got User and Tournament models, and have
the Registration relationship.  What''s the best way to create the
Registration?

Creating User#register_for has a couple upsides
1. Clients only need to know about two classes, user and tournament.
2. It reads really well.  this_user.register_for(some_tourney) is very clear
a. It''s "opinionated."  Having an explicit method at least
promotes a
single creation mechanism (it gets a letter because I''m not sure if
it''s that important)

#2 is the biggest benefit, in my opinion, and it should be obvious why
it''s good.

#1 though is interesting to me, because while you want to couple
clients to as few classes as possible, here you lose/diminish the
value of a richer model.  When you create a relationship model like
this, presumably there are some interesting attributes other than the
simple relationship.

In my case, there''s nothing else interesting (yet).  I use the join
model because it''s more flexible and no more conceptually difficult
than using HABTM.  I prefer the explicit relationship.  But maybe I
need to signify that the relationship doesn''t have interesting
attributes by abstracting it away behind the #register_for method.

So here''s my hypothesis: when there are no interesting attributes to
the relationship, create a simple method that hides the join class.
When there are interesting attributes, create the relationship object
explicitly.

Of course you can never stick to simple rules like that, but hopefully
it''s enough for you to give me another OOP lesson :)

Pat

David Chelimsky

2007-Jan-05 05:06 UTC

head link

[rspec-users] Another "how do I spec this?"

On 1/4/07, Pat Maddox <pergesu at gmail.com>
wrote:> On 1/1/07, David Chelimsky <dchelimsky at gmail.com> wrote:
> > On 1/1/07, Pat Maddox <pergesu at gmail.com> wrote:
> > > I wanted to add a convenience method on my User class to see if
he was
> > > already signed up for a tournament.  Here''s my spec
> > >
> > > context "A User signed up for one tournament" do
> > >   setup do
> > >     @t1 = Tournament.new
> > >     @t1.save false
> > >     @t2 = Tournament.new
> > >     @t2.save false
> > >     @user = User.new
> > >     @user.save false
> > >     @user.registrations << Registration.new(:tournament
=> @t1)
> > >   end
> > >
> > >   specify "should be signed up for that tournament" do
> > >     @user.should_be_signed_up_for @t1
> > >   end
> > >
> > >   specify "should not be signed up for another
tournament" do
> > >     @user.should_not_be_signed_up_for @t2
> > >   end
> > > end
> > >
> > > class User < ActiveRecord::Base
> > >   has_many :registrations
> > >
> > >   def signed_up_for?(tournament)
> > >     !registrations.find_by_tournament_id(tournament).nil?
> > >   end
> > > end
> > >
> > > Are there any potential improvements, or is that the best way to
spec it?
> >
> > Couple of thoughts. Creating new unvalidated models seems to be
> > something useful, so...
> >
> > module ModelSpecUtils
> >   def unvalidated_model(klass)
> >     model = klass.new
> >     model.save(false)
> >     model
> >   end
> > end
> >
> > Also, this line:
> >
> > @user.registrations << Registration.new(:tournament => @t1)
> >
> > is breaking encapsulation a bit. Given that and the utility module
> > above, I might end up w/ something like this:
> >
> > context "A User signed up for one tournament" do
> >   include ModelSpecUtils
> >
> >   setup do
> >     @tournament1 = unvalidated_model(Tournament)
> >     @tournament2 = unvalidated_model(Tournament)
> >     @user = unvalidated_model(User)
> >     @user.register_for(@tournament1)
> >   end
> >
> >   specify "should be signed up for that tournament" do
> >     @user.should_be_signed_up_for @tournament1
> >   end
> >
> >   specify "should not be signed up for another tournament"
do
> >     @user.should_not_be_signed_up_for @tournament2
> >   end
> > end
> >
> > David
>
> My original spec is bad, because it doesn''t show how the
Registration
> model is being used.  Right now in my controller I''m just doing
> @registration = Registration.new :tournament => @tournament, :user =>
> current_user
>
> and then saving it.  It''s probably not good then that I''m
doing
> user.registrations<< in the spec.  I know that breaks encapsulation,
> but I''m not doing it in my app.  Either way though the specs
should
> match the use.
>
> This brings up a more interesting question (to me at least.  It could
> be pointless to some).  I''ve got User and Tournament models, and
have
> the Registration relationship.  What''s the best way to create the
> Registration?
>
> Creating User#register_for has a couple upsides
> 1. Clients only need to know about two classes, user and tournament.
> 2. It reads really well.  this_user.register_for(some_tourney) is very
clear
> a. It''s "opinionated."  Having an explicit method at
least promotes a
> single creation mechanism (it gets a letter because I''m not sure
if
> it''s that important)
>
> #2 is the biggest benefit, in my opinion, and it should be obvious why
> it''s good.
>
> #1 though is interesting to me, because while you want to couple
> clients to as few classes as possible, here you lose/diminish the
> value of a richer model.  When you create a relationship model like
> this, presumably there are some interesting attributes other than the
> simple relationship.
>
> In my case, there''s nothing else interesting (yet).  I use the
join
> model because it''s more flexible and no more conceptually
difficult
> than using HABTM.  I prefer the explicit relationship.  But maybe I
> need to signify that the relationship doesn''t have interesting
> attributes by abstracting it away behind the #register_for method.
>
> So here''s my hypothesis: when there are no interesting attributes
to
> the relationship, create a simple method that hides the join class.
> When there are interesting attributes, create the relationship object
> explicitly.
That probably makes sense a lot of the time, though I can imagine a
case where there are interesting attributes in the join but it *still*
makes things most clear to do it through the user. Here''s one:

@guest = Guest.new(:smoker => false)
@hotel = Hotel.new
@hotel.should_receive(:reserve_room).with(:start_date => Time.new,
:nights => 3, :smoking_preference => "non-smoking'')
@guest.reserve_room_at(@hotel)

In this case, the guest is responsible to let the hotel know that
she''s interested in a non-smoking room rather than the controller
being responsible for asking the guest her preference and passing that
on to the hotel.
>
> Of course you can never stick to simple rules like that, but hopefully
> it''s enough for you to give me another OOP lesson :)
You''re too kind.
>
> Pat
David
> _______________________________________________
> rspec-users mailing list
> rspec-users at rubyforge.org
> http://rubyforge.org/mailman/listinfo/rspec-users
>

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