You can check operation by going to your blog post page and adding an IP address to check as a query string, e.g. <mysite>/blog/blogpost99.html?ip=18.104.22.168
(that is a comment spammer from the current list on the home page of Project Honey Pot). If it’s working, you’ll see your "blacklisted" template content instead of the comment input form.
Some test values are listed on the PH site as well, at http://www.projecthoneypot.org/httpbl_api.php
, though you can only test for one aspect at a time with them (e.g. 127.1.10.1 reacts as a comment spammer with a threat score of 10).
For a longer-term view of how it’s working, you could add some logging to the snippet, e.g. (around line 28 of the snippet) append relevant details to a log file in a protected directory or above the site root when a bad event happens.