Nice write up. Just wanted to add that the problem of using simulators or mock is that now you have one extra code base to maintain totalling: the code, the test, and the mock. For mock drivers this can be a quite big task. In the end I just preferred to run it in real hardware as much as possible and go for unit tests. This from a person that generally does not like unit tests, but there is not a very cheap way of going with simulations sometimes.