Simpletest is a Drupal module that I have been using for about a week to unit test a module I have been working on. It is a brilliant and powerful module that every module developer should be using to test their code properly. I did, however, encounter a couple of weird errors that took me a while to fix. So for the benefit of everyone else I thought I would post them here, along with the solutions. These errors are probably things that developers new to Drupal Simpletest will come across, which is why I have labelled them beginner errors.