rspec users - Oct 2010 - Testing methods that yields a block

I want to test a class method that sets some state and then yields a
block. It looks something like that:

class Cat
  class << self
     def start
           id = get_uuid
           begin
              yield if block_given?
           ensure
               set_some_other_state
           end
     end
   end
   #...
end

How can I test that id field was set? Or that set_some_other_state
method was called, if I intend to use this class like this:

Cat.start do
   # do what cat''s do
end

I''m trying to do this like this:

Cat.start { #some block }
Cat.id.should be_something

but this doesn''t work.

I also used:

Cat.should_receive(:id=).once
Cat.start {#some block}

but this doesn''t let me see to what the id field was set.

Is there a better way to test this method?

Thanks,

On Thu, Oct 7, 2010 at 9:24 AM, ignacy.moryc <imoryc at gmail.com>
wrote:
> I want to test a class method that sets some state and then yields a
> block. It looks something like that:
>
> class Cat
> ?class << self
> ? ? def start
> ? ? ? ? ? id = get_uuid
> ? ? ? ? ? begin
> ? ? ? ? ? ? ?yield if block_given?
> ? ? ? ? ? ensure
> ? ? ? ? ? ? ? set_some_other_state
> ? ? ? ? ? end
> ? ? end
> ? end
> ? #...
> end
>
> How can I test that id field was set? Or that set_some_other_state
> method was called, if I intend to use this class like this:
>
> Cat.start do
> ? # do what cat''s do
> end
>
> I''m trying to do this like this:
>
> Cat.start { #some block }
> Cat.id.should be_something
>
> but this doesn''t work.
What do you mean "doesn''t work"? Are you getting a failure
message?
What does it say?
>
> I also used:
>
> Cat.should_receive(:id=).once
> Cat.start {#some block}
>
> but this doesn''t let me see to what the id field was set.
>
> Is there a better way to test this method?
>
> Thanks,
>
>
> _______________________________________________
> rspec-users mailing list
> rspec-users at rubyforge.org
> http://rubyforge.org/mailman/listinfo/rspec-users
>

On Thu, Oct 7, 2010 at 10:24 AM, ignacy.moryc <imoryc at gmail.com> wrote:
> I want to test a class method that sets some state and then yields a
> block. It looks something like that:
>
> class Cat
>  class << self
>     def start
>           id = get_uuid
>           begin
>              yield if block_given?
>           ensure
>               set_some_other_state
>           end
>     end
>   end
>   #...
> end
>
> How can I test that id field was set? Or that set_some_other_state
> method was called, if I intend to use this class like this:
>
> Cat.start do
>   # do what cat''s do
> end
>
> I''m trying to do this like this:
>
> Cat.start { #some block }
> Cat.id.should be_something
>
> but this doesn''t work.
>
> I also used:
>
> Cat.should_receive(:id=).once
> Cat.start {#some block}
>
> but this doesn''t let me see to what the id field was set.
>
>
I think you''re seeing a legitimate failure ... You''re tripping
up against a
scoping problem in the line where you set the id.  You''re setting a
_local_
variable "id" to the value, which falls out of scope by the time your
spec
is verifying anything.

You''ll need something more like:
  self.id = get_uuid
(and possibly an attr_accessor definition for :id as well ...)

> Is there a better way to test this method?
>
> Thanks,
>
>
> _______________________________________________
> rspec-users mailing list
> rspec-users at rubyforge.org
> http://rubyforge.org/mailman/listinfo/rspec-users
>


-- 
// anything worth taking seriously is worth making fun of
// http://blog.devcaffeine.com/
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> class Cat
> ? class << self
> ? ? ?def start
> ? ? ? ? ? ?id = get_uuid
> ? ? ? ? ? ?begin
> ? ? ? ? ? ? ? yield if block_given?
> ? ? ? ? ? ?ensure
> ? ? ? ? ? ? ? ?set_some_other_state
> ? ? ? ? ? ?end
> ? ? ?end
> ? ?end
> ? ?#...
> end
In spite of the fact that you have an #id= method, `id = get_uuid` is
setting a local variable, not invoking the #id= method.  Use `self.id
= get_uuid` to invoke the method and set the attribute.

Myron