What interests me about this is that the defeat device is integral to the control system (ECM); the switch has to operate as part of the normal running of the car. The software is constantly checking the car’s behaviour to establish whether it is taking part in a federal emissions test or just running about normally. The testing of this switch would therefore have been part of the testing of the ECM. There’s no question of some separate piece of kit or software over-riding the ECM.

This means the software testers were presumably complicit in the conspiracy. If they were not complicit then that would mean that they were unaware of the existence of the different dyno and road calibrations of the ECM. They would have been so isolated from the development and the functionality of the ECM that they couldn’t have been performing any responsible, professional testing at all.

I’ve always maintained that a good tester needs to be able to speak truth to power, and any tester who simply says whatever the project manager wants to hear is not a worthwhile tester. But Christie follows that to its obvious conclusion, and raises some very important questions on the testing profession’s moral and ethical responsibilities. This is something the testing community doesn’t talk enough about.