In regards to testing, I haven’t been able to get the Selenium tests working. The PHPUnit stuff works but is a pain to develop the data to feed into the functions to properly test them, which is why I’m assuming there is so little coverage. If you wanted to spend some time learning PHP, working on the testing might be a good place to start. I haven’t finished my PR to add testing to the smart block code because I lost interest with the limited time I have to work on things. It is working but should test more scenarios and I think at this point it just tests whether the getListofFilesUnderLimit criteria loads any tracks (not the correct ones) https://github.com/LibreTime/libretime/pull/269 - If you want to play around with that it might be useful and I’d be happy if you wanted to finish it.
One last thing regarding xdebug, I was working with PHPStorm as my IDE (although Eclipse or another free IDE should work) but due to the way most of the PHP code is called by AJAX vs. being loaded directly the only way I found I was able to actually hook into the codebase was to setup my IDE to listen and then manually add the xdebug_break() function where I wanted to analyze.