Because this article covers a lot of ground, it really struck me that the term testing is ambiguous: it can mean unit-testing or user-testing. In prototyping s

Because this article covers a lot of ground, it really struck me that the term testing is ambiguous: it can mean unit-testing or user-testing. In prototyping sprints, TDD seems to acknowledge that unit-testing slows you down and creates rigidity, and therefore encourages you to just get the basic thing working without unit tests. You can throw it away, or fundamentally change the outcome, or the architecture, or the structure of the code. User-testing is how you test a prototype (including just playing with it yourself). But in building a codebase that you will live with for sometime, that will be built-on and modified and bug-fixed and tweaked, unit-testing becomes really helpful.