This folder contains motivation on tests eventhought tests are not part per se of OO Design. However, getting a master in CS without having seen and practice tests is not something that we (as experts) can let. There are our names on this lectures. So in this folder we will set the foundation of simple unit testing and this is a practice that you will be able to use during all your programmer life in ANY programming languages. In addition we added a super nice lecture about XtremTDD because - this is what we practice every single day with Pharo - and this is a glimpse of what may happen in future IDEs.