rspec users - Oct 2008 - how to catch a missing image (rspec-rails)

I want to make sure all external resources called for by my views (like
images) actually exist.  How do I write an rspec that will fail when an
image included on the page isn''t present?


For example, let''s say in application.html.erb, I include <img
src="/images/mylogo.png">, but that file doesn''t exist
(say it''s
actually /images/mylogo.jpg).

When this is run on the server, the image won''t appear, and the server
log will show an error like this:

 >> ActionController::RoutingError (No route matches
"/images/mylogo.png" with
 >> {:method=>:get}):

However, views tests like response.should have_tag(img[src=/mylogo.png/)
won''t catch it, because the tag will be there.    controllers tests
(with integrate_views on) for response.should be_success,
render_template won''t catch it because the page itself was a success
and
rendered the template.

But an error was thrown during a second connection to the server,
because the image file didn''t exist ... there must be a way for any
such
failures.  How?

Thanks!
Ev
-- 
Posted via http://www.ruby-forum.com/.

Evan Dorn <lists at ruby-forum.com> writes:
> I want to make sure all external resources called for by my views (like
> images) actually exist.  How do I write an rspec that will fail when an
> image included on the page isn''t present?
>
>
> For example, let''s say in application.html.erb, I include <img
> src="/images/mylogo.png">, but that file doesn''t
exist (say it''s
> actually /images/mylogo.jpg).
>
> When this is run on the server, the image won''t appear, and the
server
> log will show an error like this:
>
>  >> ActionController::RoutingError (No route matches
> "/images/mylogo.png" with
>  >> {:method=>:get}):
>
> However, views tests like response.should have_tag(img[src=/mylogo.png/)
> won''t catch it, because the tag will be there.    controllers
tests
> (with integrate_views on) for response.should be_success,
> render_template won''t catch it because the page itself was a
success and
> rendered the template.
>
> But an error was thrown during a second connection to the server,
> because the image file didn''t exist ... there must be a way for
any such
> failures.  How?
Hi Evan,

Can you rely on the convention that images are under RAILS_ROOT/public?
If so, you could do a little translucent-box testing.  Maybe you could
use hpricot to get all the image elements and check their referenced
file''s existence.

# I''m just BSing the hpricot
hpricot("doc/img") do |element|
  element.attr(''src'').should be_existing_resource 
end

Where be_existing_resource is a custom matcher with a simple
implementation of

def matches?(actual)
  File.exists?(File.expand_path(RAILS_ROOT + actual))
end

(simple enough for a simple matcher, even)

This should give you a good deal of confidence without any hassle.

Pat