rspec users - Apr 2009 - Testing helpers that accept a block

Hi,

I am trying to write and test a helper that accepts a block. Right now it
goes something like this:

module ContactHelper
  
  # Wraps a field with div.error if it has an error.
  def wrap_error_field errors, &block
    field = capture &block
    if errors.empty?
      concat field
    else
      concat content_tag(:div, field, :class => ''error'')
    end
  end # field_error_helper
  
This is my first time writing a helper, so please tell me if I''m wrong.

Then, I tried to test it, but couldn''t figure it out, since it seems
the
method won''t actually return anything due to the use of concat. The
best I
could figure out for now was to use eval_erb.

require File.expand_path(File.dirname(__FILE__) +
''/../spec_helper'')

describe ContactHelper do
  
  describe "field_error_helper" do
    
    context "when there is an error" do
      
      it "should wrap the block in div.error" do
        
        assigns[:errors] = [
          ''Error''
        ]
        
        output = eval_erb <<-ERB
          <% wrap_error_field @errors do %>
            <p>Block</p>
            <% end %>
        ERB
        
        assert_xhtml output do
          div.error do
            p ''Block''
          end
        end
        
      end # it should wrap the block in div.error
      
    end # when there is an error
    
  end # describe field_error_helper
  
end
end

Is that the best/only method? I''m not sure how much I really like it.

Further, when I run the tests, it always outputs "Block" before the
test is
executed, and I can''t figure out why, and that''s slightly
annoying.

Thanks,
Brandon

Hi,

Well, I googled some more, and everything I could find used eval_erb. So is
this the best method for testing helpers with blocks?

And then why is that block displaying when I run the test?

Thanks,
Brandon
> -----Original Message-----
> From: Brandon Olivares [mailto:programmer2188 at gmail.com]
> Sent: Wednesday, April 08, 2009 6:25 AM
> To: ''rspec-users''
> Subject: Testing helpers that accept a block
> 
> Hi,
> 
> I am trying to write and test a helper that accepts a block. Right now
> it goes something like this:
> 
> module ContactHelper
> 
>   # Wraps a field with div.error if it has an error.
>   def wrap_error_field errors, &block
>     field = capture &block
>     if errors.empty?
>       concat field
>     else
>       concat content_tag(:div, field, :class =>
''error'')
>     end
>   end # field_error_helper
> 
> This is my first time writing a helper, so please tell me if I''m
wrong.
> 
> Then, I tried to test it, but couldn''t figure it out, since it
seems
> the method won''t actually return anything due to the use of
concat. The
> best I could figure out for now was to use eval_erb.
> 
> require File.expand_path(File.dirname(__FILE__) +
''/../spec_helper'')
> 
> describe ContactHelper do
> 
>   describe "field_error_helper" do
> 
>     context "when there is an error" do
> 
>       it "should wrap the block in div.error" do
> 
>         assigns[:errors] = [
>           ''Error''
>         ]
> 
>         output = eval_erb <<-ERB
>           <% wrap_error_field @errors do %>
>             <p>Block</p>
>             <% end %>
>         ERB
> 
>         assert_xhtml output do
>           div.error do
>             p ''Block''
>           end
>         end
> 
>       end # it should wrap the block in div.error
> 
>     end # when there is an error
> 
>   end # describe field_error_helper
> 
> end
> end
> 
> Is that the best/only method? I''m not sure how much I really like
it.
> 
> Further, when I run the tests, it always outputs "Block" before
the
> test is executed, and I can''t figure out why, and that''s
slightly
> annoying.
> 
> Thanks,
> Brandon

>         assert_xhtml output do
>           div.error do
>             p ''Block''
>           end
>         end
Nokogiri has some "easter eggs" in its ambitious HTML::Builder system.
One of
them is only HTML tags not already recognized as methods can get turned into 
HTML tags. The usual .method_missing() abuse.

The fix is:

         assert_xhtml output do
           div.error do
             p! ''Block''
           end
         end

(Also .be_html_with might work by now... 0.4.9?)

Aaron P. is pondering this issue even now in his subconscious, but I only ought 
to feed him one feature request at a time and a couple others are ahead in the 
queue, so my ! trick has to work for the near future...

Hi,

Oh, I should have thought of that. Thanks a lot.

I''m growing used to the assert_xhtml syntax, lol, so I''ve just
been using
that. Thank you though for fixing the be_html_with syntax.

Brandon
> -----Original Message-----
> From: rspec-users-bounces at rubyforge.org [mailto:rspec-users-
> bounces at rubyforge.org] On Behalf Of Phlip
> Sent: Wednesday, April 08, 2009 11:54 PM
> To: rspec-users at rubyforge.org
> Subject: Re: [rspec-users] Testing helpers that accept a block
> 
> >         assert_xhtml output do
> >           div.error do
> >             p ''Block''
> >           end
> >         end
> 
> Nokogiri has some "easter eggs" in its ambitious HTML::Builder
system.
> One of
> them is only HTML tags not already recognized as methods can get turned
> into
> HTML tags. The usual .method_missing() abuse.
> 
> The fix is:
> 
>          assert_xhtml output do
>            div.error do
>              p! ''Block''
>            end
>          end
> 
> (Also .be_html_with might work by now... 0.4.9?)
> 
> Aaron P. is pondering this issue even now in his subconscious, but I
> only ought
> to feed him one feature request at a time and a couple others are ahead
> in the
> queue, so my ! trick has to work for the near future...
> 
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