add a library for generating test suites for a given state machine

[exarkun]

Since the states are known and the inputs are known it's possible to generate a list of all of the possible scenarios that the state machine is supposed to handle. It's reasonable to say that each of these must have at least one unit test.

A library can generate a TestCase (or a mixin or something) that defines one test for each of these cases and gives them failing implementations that need to be overridden. This will give developers a very easy way to know the minimum set of tests they still haven't written.

Possibly there's a better interface than "a thing you can subclass" for this - but it's not immediately obvious to me since the way unittest works is pretty firmly "subclass this thing". (But... like... a class decorator maybe?)

[exarkun]

Perhaps an alternative to subclassing is a class decorator which inspects the decorated class and adds new failing tests for any transitions that appear not to be tested. As with the subclassing idea, this would involve a particular naming convention for test methods so the decorator could accurately determine which cases had tests written for them.