Problems matching generated html output

luislavena · November 3, 2011, 11:51pm

So, I am writing tests for a presenter class that outputs html markup.

I have a method that does something like this:

def output

things.map do |thing|

content_tag :div, :id => thing[:id] do
 [content_tag :p, thing[:body_1],
 content_tag :p, thing[:body_2].join.html_safe

end

end.join.html_safe

end

…

Then my spec is something like this:

it “returns markup” do

@presenter.stubs(:things).returns({:id => “an_id”, :body_1 => “hello”,
:body_2 => “goodbye”})

@presenter.output.should == filter_for_html("

<div id="an_id">
  <p>hello</p>
  <p>goodbye</p>
 </div>

")
end

and I made this filter_for_html helper method which allows me to not
care about
whitespace… So that just does:

def filter_for_html(markup)
markup.squeeze(" ").strip.gsub(/\n\s+/, “”)
end

And this effctively strips out all the whitespace and gives me a string
like:
“

hello

goodbye

”

…

– END OF BACKGROUND EXPLANATION –

Now for my question— I have two problems and am not sure what the best
to
solve either one is:

The match fails because content_tag apparently inserts in a few \n’s
here
and there.
My background explanation was actually quite simplified, and my
presenter
class is actually rendering some haml partials, and something like
%ul.foo
turns into
- Some of the text generated via the partials is calling things like
  .humanize which capitalize text and I am not really concerned about
  those
  details in my test…

So the way I got my test passing is to do:

@presenter.output.gsub(“\n”, “”).gsub(“'”, “"”).downcase.should ==
filter_for_html(’ … same content as before … ')

Which I don’t know about you, but that makes me go “ewwwwwwwwww”. And
makes
all the RSpec readibility go out the window. Is there something I
should be
doing with a custom matcher or something to test for case-indifferent
text,
ignore whitespace and \n, and be quote indifferent?

Thanks.

Patrick J. Collins
http://collinatorstudios.com

cghost · November 4, 2011, 12:14am

On 3 Nov 2011, at 22:36, Patrick J. Collins wrote:

 content_tag :p, thing[:body_2].join.html_safe
it “returns markup” do
")
“

hello

goodbye

”

So the way I got my test passing is to do:
Patrick J. Collins
http://collinatorstudios.com

I realise this isn’t the answer you’re looking for, but I’m curious:
where did you get the idea that a presenter should know anything about
HTML?

cheers,
Matt

–
Freelance programmer & coach
Author, Search (with Aslak
Hellesy)
Founder, http://relishapp.com
+44(0)7974430184 | http://twitter.com/mattwynne

cghost · November 4, 2011, 12:27am

I realise this isn’t the answer you’re looking for, but I’m curious: where
did you get the idea that a presenter should know anything about HTML?

Maybe I am using the wrong terminology then. I always thought
presenters were
classes that output presentational content… If you have a view with a
lot of
dynamic content, the conditional logic ends up building to the point
where the
view is unreadable, and if you try to refactor out into helper methods,
you end
up having something like

module MyHelper

def something(lol)
modify_lol(lol)
end

def modify_lol(lol)
do_something_else_with_lol(lol)
end

… etc

end

A class helps to eliminate this problem by giving you a way to
instantiate with
instance variables and cut down on having pass around the same variable
to
multiple helpers… I’ve always called that a presenter, and in this
case
it deals with HTML. Am I totally on crack?

Patrick J. Collins
http://collinatorstudios.com

cghost · November 4, 2011, 3:27am

On Nov 3, 2011, at 4:07 PM, Patrick J. Collins wrote:

So, I am writing tests for a presenter class that outputs html markup.

Actually now that I am thinking about it… Would you guys recommend that I use
something like Nokogiri to parse the content and test for things like number of
children, classes, ids, etc, rather than just comparing the raw HTML?

Yes, definitely. Also you might be interested in
GitHub - nakajima/elementor: View testing that doesn't suck. although I haven’t used it in a
long time so I don’t know how up to date it is.

As far as your other question goes about how to use presenters, you
probably don’t want them emitting HTML. Instead you want the presenter
to provide a simpler interface to some commonly accessed data that you
don’t think belongs on the model. An example might be

class UserPresenter
def initialize(user)
@user = user
end

def full_name
@user.first_name + ’ ’ + @user.last_name
end
end

Ignoring whether this is an appropriate case for using a presenter, you
can see what I’m accomplishing here. And hopefully you can imagine it
being more useful if there are multiple models involved.

A presenter is basically the facade pattern used specifically for
presentation logic.

Pat

http://c2.com/cgi/wiki?FacadePattern

cghost · November 4, 2011, 10:52am

On 3 Nov 2011, at 23:25, Patrick J. Collins wrote:

I realise this isn’t the answer you’re looking for, but I’m curious: where
did you get the idea that a presenter should know anything about HTML?

Maybe I am using the wrong terminology then. I always thought presenters were
classes that output presentational content

Well, in any discussion I’ve seen of the pattern, that’s the job of the
view.

MVP / Passive View[1][2] is quite a well-established pattern in
curly-bracket languages, and the presenter’s job in that pattern is to
tell the view, at a logical level, what to show. The view is then just
left with the simple job of showing it. The idea being that you could
use the same presenter with a view for a web app, a view for a
rich-client GUI, or a view for a mobile app. In theory.

This makes them both much easier to test.

Steve K. has been writing about their application in the Ruby /
Rails world recently[3]

[1] Passive View
[2]
Vacation Rental Hacks
[3]
http://blog.steveklabnik.com/2011/09/06/the-secret-to-rails-oo-design.html

cheers,
Matt

–
Freelance programmer & coach
Author, Search (with Aslak
Hellesy)
Founder, http://relishapp.com
+44(0)7974430184 | http://twitter.com/mattwynne

cghost · November 4, 2011, 12:49am

So, I am writing tests for a presenter class that outputs html markup.

Actually now that I am thinking about it… Would you guys recommend
that I use
something like Nokogiri to parse the content and test for things like
number of
children, classes, ids, etc, rather than just comparing the raw HTML?

Patrick J. Collins
http://collinatorstudios.com