It would be convenient and useful if the test system could automatically check every <a href> in a rendered page to make sure the links did not cause 404s.
Obviously, for pages with dozens of links, this could take a long time to run. So I suggest an only_internal keyword argument, which would be True by default and would cause only the *internal* links (i.e., those without an "https?://") to be checked, thereby using Django's internal URL resolving to check the links instead of going over HTTP.
In the documentation for this feature, we should note that people should ensure none of their pages have side effects, because this test will essentially cause all links to be "clicked on."