@Gregory Salvam, Since I read the "Agile Java" book by Jeff Langr, I thought that using TDD to learn a programming language was very useful and I used it both for myself and for teaching. However, I had not thought of applying this concept in the way you expressed it, that is, using the 4 rules of simple design (by Beck :-) even if I better understood them reading Corey Haines) to test the assertions contained in the language manual. It seems to me a very interesting approach that I will try to apply as soon as I have the opportunity/need. Thank you!