So?
I'm not sure if you noticed, but while Iran has sponsored and to some degree still does sponsor terrorism, Saudi Arabia was the source of most of the 9/11 hijackers...and is the home of the Wahabbi Sunni sect whose teachings ISIS took and cranked up to 11 on a 1-to-10 scale as they tried to impose their "Caliphate" in what's supposed to be Iraq and Syria...so you have to ask yourself who, really, cost America more in terms of blood and treasure. Here's a hint: it ain't Iran. The only reasons that we stay so friendly with Saudi Arabia are to keep their oil flowing, and to keep them purchasing our weapons systems (depending on whose word you take,
Saudi Arabia spends either slightly less or significantly more on defense than freaking Russia).
If we were smart, we'd do like China - be friendly to both Saudi Arabia and Iran, sell to both, and when they go to war (as they eventually will since they hate each other FAR more than they hate either America or Israel - yes, they do), we sit on the sidelines with a bag of popcorn and wait to do business with the winner.
One last thing - neither one will attack Israel even with nukes since Israel has 200+ nukes of their own, and would certainly incur the wrath of America and much of the rest of the world. They won't attack each other with nukes because neither one dare threaten their holy site of Mecca...and they both know that whoever uses a nuclear weapon against anyone else will be immediately ostracized, its borders closed to all, its economy ruined, and its leaders declared war criminals...and that's if we ourselves don't go in guns a-blazing.
So relax - MAD (Mutual Assured Destruction) works between smaller nations, too. The only real threat is terrorist attacks using nuclear weapons (whether as nuclear bombs or "dirty bombs") - and the degree to which Iran tests ballistic missiles has no bearing on their current inability (thanks to the agreement signed and supported by NATO, Russia, China, and America) to develop nuclear weapons. In fact, the only real reason y'all hate the agreement so much isn't because of how effective it is or isn't, but because it was that hated black guy in the White House who made it happen, who actually got NATO, Russia, and China to
all support the agreement.