simpletests for Drupal6 Pathauto

I'd like to keep Drupal6.x-1 and Drupal5.x-2 in sync with each other at least for the foreseeable future. I'd also like to get to a point where some automated testing (and therefore I guess that means simpletest) can help prevent regressions when new features and bugfixes are added. The idea of this issue is to create the simpletests for D6 and then after that we can move to a system where all new development is done under D6 and then backported.