How to catch a missing image (rspec-rails)

Testing RSpec
1

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 , 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

2

Evan D. [email protected] writes:

log will show an error like this:

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