rspec users - Dec 2006 - should_be_different -- possible implementation

There is an assert_difference helper for Test::Unit (you can read  
about it at http://blog.caboo.se/articles/2006/06/13/a-better- 
assert_difference and to some it should look familiar -- you know who  
you are :), so I took a shot at one for rSpec on Rails.


class Object
     def should_be_different(method = nil, difference = nil)
         return self.should_not_eql(yield) if method.nil?

         before = self.send(method)
         yield
         return self.send(method).should_not_eql(before) if  
difference.nil?
         (self.send(method) - before).should_eql difference
     end
end


Usage:

     specify "should be able to create a new user" do
         Person.create(:name => ''joe'')
         Person.should_be_different :count do
             Person.create(:name => ''bob'')
         end
     end

This has probably already been done, but I thought I''d put it out  
here for comment in case it hadn''t. Note that if you omit the method,  
the objects are tested for equality (however the object defines it).  
If you include the method but omit the difference, then any amount  
difference is ok. Testing destroy might indicate using -1 for the  
difference to indicate that the count has gone down.

My implementation works, but a more natural syntax would be:

Person.count.should_be_different do
	blah
end

and:

Person.count.should_be_different_by 1 do
	blah, blah
end

Comments?

Steve

On 12/4/06, s.ross <cwdinfo at gmail.com> wrote:
> There is an assert_difference helper for Test::Unit (you can read
> about it at http://blog.caboo.se/articles/2006/06/13/a-better-
> assert_difference and to some it should look familiar -- you know who
> you are :), so I took a shot at one for rSpec on Rails.
We''ve already got this in 0.7.4. It''s called assert_change,
but it''s
the same functionality you''re looking for:

http://rspec.rubyforge.org/documentation/expectations.html

Cheers,
David
>
>
> class Object
>      def should_be_different(method = nil, difference = nil)
>          return self.should_not_eql(yield) if method.nil?
>
>          before = self.send(method)
>          yield
>          return self.send(method).should_not_eql(before) if
> difference.nil?
>          (self.send(method) - before).should_eql difference
>      end
> end
>
>
> Usage:
>
>      specify "should be able to create a new user" do
>          Person.create(:name => ''joe'')
>          Person.should_be_different :count do
>              Person.create(:name => ''bob'')
>          end
>      end
>
> This has probably already been done, but I thought I''d put it out
> here for comment in case it hadn''t. Note that if you omit the
method,
> the objects are tested for equality (however the object defines it).
> If you include the method but omit the difference, then any amount
> difference is ok. Testing destroy might indicate using -1 for the
> difference to indicate that the count has gone down.
>
> My implementation works, but a more natural syntax would be:
>
> Person.count.should_be_different do
>         blah
> end
>
> and:
>
> Person.count.should_be_different_by 1 do
>         blah, blah
> end
>
> Comments?
>
> Steve
>
> _______________________________________________
> rspec-users mailing list
> rspec-users at rubyforge.org
> http://rubyforge.org/mailman/listinfo/rspec-users
>

On 12/4/06, David Chelimsky <dchelimsky at gmail.com>
wrote:
> On 12/4/06, s.ross <cwdinfo at gmail.com> wrote:
> > There is an assert_difference helper for Test::Unit (you can read
> > about it at http://blog.caboo.se/articles/2006/06/13/a-better-
> > assert_difference and to some it should look familiar -- you know who
> > you are :), so I took a shot at one for rSpec on Rails.
>
> We''ve already got this in 0.7.4. It''s called
assert_change, but it''s
> the same functionality you''re looking for:
>
Typo: It''s called should_change
> http://rspec.rubyforge.org/documentation/expectations.html
>
> Cheers,
> David
>
> >
> >
> > class Object
> >      def should_be_different(method = nil, difference = nil)
> >          return self.should_not_eql(yield) if method.nil?
> >
> >          before = self.send(method)
> >          yield
> >          return self.send(method).should_not_eql(before) if
> > difference.nil?
> >          (self.send(method) - before).should_eql difference
> >      end
> > end
> >
> >
> > Usage:
> >
> >      specify "should be able to create a new user" do
> >          Person.create(:name => ''joe'')
> >          Person.should_be_different :count do
> >              Person.create(:name => ''bob'')
> >          end
> >      end
> >
> > This has probably already been done, but I thought I''d put it
out
> > here for comment in case it hadn''t. Note that if you omit the
method,
> > the objects are tested for equality (however the object defines it).
> > If you include the method but omit the difference, then any amount
> > difference is ok. Testing destroy might indicate using -1 for the
> > difference to indicate that the count has gone down.
> >
> > My implementation works, but a more natural syntax would be:
> >
> > Person.count.should_be_different do
> >         blah
> > end
> >
> > and:
> >
> > Person.count.should_be_different_by 1 do
> >         blah, blah
> > end
> >
> > Comments?
> >
> > Steve
> >
> > _______________________________________________
> > rspec-users mailing list
> > rspec-users at rubyforge.org
> > http://rubyforge.org/mailman/listinfo/rspec-users
> >
> _______________________________________________
> rspec-users mailing list
> rspec-users at rubyforge.org
> http://rubyforge.org/mailman/listinfo/rspec-users
>

On 12/4/06, aslak hellesoy <aslak.hellesoy at gmail.com>
wrote:
> On 12/4/06, David Chelimsky <dchelimsky at gmail.com> wrote:
> > On 12/4/06, s.ross <cwdinfo at gmail.com> wrote:
> > > There is an assert_difference helper for Test::Unit (you can read
> > > about it at http://blog.caboo.se/articles/2006/06/13/a-better-
> > > assert_difference and to some it should look familiar -- you know
who
> > > you are :), so I took a shot at one for rSpec on Rails.
> >
> > We''ve already got this in 0.7.4. It''s called
assert_change, but it''s
> > the same functionality you''re looking for:
> >
>
> Typo: It''s called should_change
LOL

I got half way there.

>
> > http://rspec.rubyforge.org/documentation/expectations.html
> >
> > Cheers,
> > David
> >
> > >
> > >
> > > class Object
> > >      def should_be_different(method = nil, difference = nil)
> > >          return self.should_not_eql(yield) if method.nil?
> > >
> > >          before = self.send(method)
> > >          yield
> > >          return self.send(method).should_not_eql(before) if
> > > difference.nil?
> > >          (self.send(method) - before).should_eql difference
> > >      end
> > > end
> > >
> > >
> > > Usage:
> > >
> > >      specify "should be able to create a new user" do
> > >          Person.create(:name => ''joe'')
> > >          Person.should_be_different :count do
> > >              Person.create(:name => ''bob'')
> > >          end
> > >      end
> > >
> > > This has probably already been done, but I thought I''d
put it out
> > > here for comment in case it hadn''t. Note that if you
omit the method,
> > > the objects are tested for equality (however the object defines
it).
> > > If you include the method but omit the difference, then any
amount
> > > difference is ok. Testing destroy might indicate using -1 for the
> > > difference to indicate that the count has gone down.
> > >
> > > My implementation works, but a more natural syntax would be:
> > >
> > > Person.count.should_be_different do
> > >         blah
> > > end
> > >
> > > and:
> > >
> > > Person.count.should_be_different_by 1 do
> > >         blah, blah
> > > end
> > >
> > > Comments?
> > >
> > > Steve
> > >
> > > _______________________________________________
> > > rspec-users mailing list
> > > rspec-users at rubyforge.org
> > > http://rubyforge.org/mailman/listinfo/rspec-users
> > >
> > _______________________________________________
> > rspec-users mailing list
> > rspec-users at rubyforge.org
> > http://rubyforge.org/mailman/listinfo/rspec-users
> >
> _______________________________________________
> rspec-users mailing list
> rspec-users at rubyforge.org
> http://rubyforge.org/mailman/listinfo/rspec-users
>

Did the syntax discussion ever get settled. The signature is  
should_change(receiver, message) but there were discussions in this  
thread:

http://rubyforge.org/pipermail/rspec-devel/2006-November/001251.html

That discussed lots of cool syntactic sugar. What was settled upon?

Person.should_change :count do
	Person.create(:name => ''ozzy osbourne'')
end

How do you specify by how much?

Thx


On Dec 4, 2006, at 10:33 AM, David Chelimsky wrote:
> On 12/4/06, aslak hellesoy <aslak.hellesoy at gmail.com> wrote:
>> On 12/4/06, David Chelimsky <dchelimsky at gmail.com> wrote:
>>> On 12/4/06, s.ross <cwdinfo at gmail.com> wrote:
>>>> There is an assert_difference helper for Test::Unit (you can
read
>>>> about it at http://blog.caboo.se/articles/2006/06/13/a-better-
>>>> assert_difference and to some it should look familiar -- you  
>>>> know who
>>>> you are :), so I took a shot at one for rSpec on Rails.
>>>
>>> We''ve already got this in 0.7.4. It''s called
assert_change, but it''s
>>> the same functionality you''re looking for:
>>>
>>
>> Typo: It''s called should_change
>
> LOL
>
> I got half way there.
>
>
>>
>>> http://rspec.rubyforge.org/documentation/expectations.html
>>>
>>> Cheers,
>>> David
>>>
>>>>
>>>>
>>>> class Object
>>>>      def should_be_different(method = nil, difference = nil)
>>>>          return self.should_not_eql(yield) if method.nil?
>>>>
>>>>          before = self.send(method)
>>>>          yield
>>>>          return self.send(method).should_not_eql(before) if
>>>> difference.nil?
>>>>          (self.send(method) - before).should_eql difference
>>>>      end
>>>> end
>>>>
>>>>
>>>> Usage:
>>>>
>>>>      specify "should be able to create a new user" do
>>>>          Person.create(:name => ''joe'')
>>>>          Person.should_be_different :count do
>>>>              Person.create(:name => ''bob'')
>>>>          end
>>>>      end
>>>>
>>>> This has probably already been done, but I thought I''d
put it out
>>>> here for comment in case it hadn''t. Note that if you
omit the
>>>> method,
>>>> the objects are tested for equality (however the object defines
>>>> it).
>>>> If you include the method but omit the difference, then any
amount
>>>> difference is ok. Testing destroy might indicate using -1 for
the
>>>> difference to indicate that the count has gone down.
>>>>
>>>> My implementation works, but a more natural syntax would be:
>>>>
>>>> Person.count.should_be_different do
>>>>         blah
>>>> end
>>>>
>>>> and:
>>>>
>>>> Person.count.should_be_different_by 1 do
>>>>         blah, blah
>>>> end
>>>>
>>>> Comments?
>>>>
>>>> Steve
>>>>
>>>> _______________________________________________
>>>> rspec-users mailing list
>>>> rspec-users at rubyforge.org
>>>> http://rubyforge.org/mailman/listinfo/rspec-users
>>>>
>>> _______________________________________________
>>> rspec-users mailing list
>>> rspec-users at rubyforge.org
>>> http://rubyforge.org/mailman/listinfo/rspec-users
>>>
>> _______________________________________________
>> rspec-users mailing list
>> rspec-users at rubyforge.org
>> http://rubyforge.org/mailman/listinfo/rspec-users
>>
> _______________________________________________
> rspec-users mailing list
> rspec-users at rubyforge.org
> http://rubyforge.org/mailman/listinfo/rspec-users

On 12/4/06, s.ross <cwdinfo at gmail.com> wrote:
> Did the syntax discussion ever get settled.
http://rspec.rubyforge.org/documentation/expectations.html
> The signature is
> should_change(receiver, message) but there were discussions in this
> thread:
>
> http://rubyforge.org/pipermail/rspec-devel/2006-November/001251.html
>
> That discussed lots of cool syntactic sugar. What was settled upon?
>
> Person.should_change :count do
>         Person.create(:name => ''ozzy osbourne'')
> end
>
> How do you specify by how much?
>
> Thx
>
>
> On Dec 4, 2006, at 10:33 AM, David Chelimsky wrote:
>
> > On 12/4/06, aslak hellesoy <aslak.hellesoy at gmail.com> wrote:
> >> On 12/4/06, David Chelimsky <dchelimsky at gmail.com> wrote:
> >>> On 12/4/06, s.ross <cwdinfo at gmail.com> wrote:
> >>>> There is an assert_difference helper for Test::Unit (you
can read
> >>>> about it at
http://blog.caboo.se/articles/2006/06/13/a-better-
> >>>> assert_difference and to some it should look familiar --
you
> >>>> know who
> >>>> you are :), so I took a shot at one for rSpec on Rails.
> >>>
> >>> We''ve already got this in 0.7.4. It''s called
assert_change, but it''s
> >>> the same functionality you''re looking for:
> >>>
> >>
> >> Typo: It''s called should_change
> >
> > LOL
> >
> > I got half way there.
> >
> >
> >>
> >>> http://rspec.rubyforge.org/documentation/expectations.html
> >>>
> >>> Cheers,
> >>> David
> >>>
> >>>>
> >>>>
> >>>> class Object
> >>>>      def should_be_different(method = nil, difference =
nil)
> >>>>          return self.should_not_eql(yield) if method.nil?
> >>>>
> >>>>          before = self.send(method)
> >>>>          yield
> >>>>          return self.send(method).should_not_eql(before)
if
> >>>> difference.nil?
> >>>>          (self.send(method) - before).should_eql
difference
> >>>>      end
> >>>> end
> >>>>
> >>>>
> >>>> Usage:
> >>>>
> >>>>      specify "should be able to create a new
user" do
> >>>>          Person.create(:name =>
''joe'')
> >>>>          Person.should_be_different :count do
> >>>>              Person.create(:name =>
''bob'')
> >>>>          end
> >>>>      end
> >>>>
> >>>> This has probably already been done, but I thought
I''d put it out
> >>>> here for comment in case it hadn''t. Note that if
you omit the
> >>>> method,
> >>>> the objects are tested for equality (however the object
defines
> >>>> it).
> >>>> If you include the method but omit the difference, then
any amount
> >>>> difference is ok. Testing destroy might indicate using -1
for the
> >>>> difference to indicate that the count has gone down.
> >>>>
> >>>> My implementation works, but a more natural syntax would
be:
> >>>>
> >>>> Person.count.should_be_different do
> >>>>         blah
> >>>> end
> >>>>
> >>>> and:
> >>>>
> >>>> Person.count.should_be_different_by 1 do
> >>>>         blah, blah
> >>>> end
> >>>>
> >>>> Comments?
> >>>>
> >>>> Steve
> >>>>
> >>>> _______________________________________________
> >>>> rspec-users mailing list
> >>>> rspec-users at rubyforge.org
> >>>> http://rubyforge.org/mailman/listinfo/rspec-users
> >>>>
> >>> _______________________________________________
> >>> rspec-users mailing list
> >>> rspec-users at rubyforge.org
> >>> http://rubyforge.org/mailman/listinfo/rspec-users
> >>>
> >> _______________________________________________
> >> rspec-users mailing list
> >> rspec-users at rubyforge.org
> >> http://rubyforge.org/mailman/listinfo/rspec-users
> >>
> > _______________________________________________
> > rspec-users mailing list
> > rspec-users at rubyforge.org
> > http://rubyforge.org/mailman/listinfo/rspec-users
>
> _______________________________________________
> rspec-users mailing list
> rspec-users at rubyforge.org
> http://rubyforge.org/mailman/listinfo/rspec-users
>