Test presence of javcascript code/snippet with rspec capybara (Rails 4)

I'd like to create a test to make sure my third party tools (js scripts) are present (for example, to make sure nobody in the team removed it by accident!)

Here are 2 javascript third party tool that are loaded on my homepage view whose presence i'd like to test:

<script type="text/javascript">
var clicky_site_ids = clicky_site_ids || [];
xxxxxxxxxxxxxxxxxxxxxxxxx
(function() {
  var s = document.createElement('script');
  s.type = 'text/javascript';
  s.async = true;
  s.src = '//static.getclicky.com/js';
  ( document.getElementsByTagName('head')[0] || document.getElementsByTagName('body')[0] ).appendChild( s );
})();
</script>

<script src="//src.melvinize.io/r.js"></script>

Here are my rspec test (I'm using Capybara with webkit driver)

describe "third party tools are present inside source code", js: true do

it 'should have js trackings' do
  visit(root_path)
  all('script').find { |s| s[:src].match /getclicky\.js$/ }.should_not be_nil
  all('script').find ("//static.getclicky.com/js").should_not be_nil

  all('script').find ("//src.melvinize.io/r.js").should_not be_nil
end 

end

My test does not work as it always pass (!), but i'm a rookie with this kind of tests using regular expressions and I'm not even sure that's the right way to do it.

thanks for any help, Mathieu