Ahh, this is the kind of thinking that frustrated me in my time as a software tester.<p>From a functionality perspective: maybe, but if the developer needs to explain the intended functionality of the application to the business end of the product then something has gone horribly wrong.<p>From a sheer &quot;finding bugs&quot; perspective:  If you knew what would actually expose buggy functionality to the extent that you could write it down, you wouldn&#x27;t have written that in the first place!<p>I encourage you to teach him the way that your specific language makes things happen on the machine and the way that software in general works (boundary conditions, etc).  But I don&#x27;t think that the above way of doing things, ESPECIALLY for a 2 man outfit, is a good idea.