Historical note : Hudson is what Jenkins was called a long time ago.

I want the drupal user uploaded files to be manageable by both apache and a non-root user

In my case I’m using hudson to rebuild the site with data and “files” from live periodically.

Hudson http://hudson-ci.org/ is a continuous integration server - it runs and monitors ‘jobs’ in a way that is useful to regularly build software and report on any errors.

Selenium http://seleniumhq.org/ is a suite of tools specifically for testing web applications - it tests the full website by automating the running of one or more browsers (so you can test all that pointy clicky ajaxy stuff)