[chairmanwow]

I’m not sure about this. This kind of integration test would almost certainly be performed in a closed course (parking lot / garage).

[earenndil]

Well, as an initial test, sure, but you have to do the same test in an open road once you know it works in isolation.

[hwillis]

It probably also makes sense to do it in an environment with lots of reflections of different kinds. If you were genuinely worried about your primary sensor getting bad data, you definitely wouldn't test four of them together in the real world until you were quite sure they would be fine. Just imagine two of them taking off at the light and swerving wildly around phantom cars!