Just jumping in here, I don't understand what this method is testing.  There's content, and we're expanding urls in it, presumably shortened urls, so we pass a short url into the expander (?) and the result is the no content changed? 

On review, again, without looking at the implementation, it looks like the method is looking for anchor tag hrefs with relative links and prefixing them to make them absolute.  i.e. convert_relative_links_to_absolute

so this test is really testing that if there are no href attributes, the href attributes aren't modified?