Certainly, you could see how they’d want to test these things. I mean, it’s no use having such substantial items if you don’t know if they work, or how well they work. And isn’t the point of having these things the idea that, if needed, they would actually function? That they would do what they were designed to do? So yes, it’s understandable and not really alarming that practice would be required. Or, it would be not alarming, if the “they” in question weren’t North Korea, and the “things” weren’t ballistic missiles.