This is just one test, but we can hand the tool to our customer now (thats us with our customer hat on, but an actual human could do it) and the customer can write more tests. We know that when he does, well get some requests . Well have a need to set the cursor position. We might have a need to have incorrect files report an error, such as files that do no checking of *output. And, of course, there will be new editing instructions and new commands.
We already know what the next story will be. Our customer wants us to implement a File menu, with Save and New and Open. Well probably split that story and do Save first. Probably before that happens, however, the customer will write some more tests and break our tiny framework. But thats OK, because we dont have a frameworkwe have tests. And thats the bottom line:
We dont need a testing framework. We need tests!