all NORAD software upgrades should be tested by launching a full scale attack against the United States. That's absurd.

The Patriot missile was designed as an antiaircraft weapon and was tested against target drones. Later, they expanded the mission to include intercepting tactical missiles like the Scud. It turned out there were a couple problems: 1) the missile used a warhead to destroy the target instead of kinetic energy impact, and 2) the internal clock tended to be unaccurate over long periods of time.

The two problems are related. In order to detonate the warhead against a missile coming in at something like Mach 5, the detonation time has to be accurate to within milliseconds. As the system clock drifted off the correct time, the chances of accuracy decreased. Many of the Patriot missiles did damage the Scud's rocket bodies but failed to detonate the warhead. It was a timing issue that didn't show up until the system had been up and running for a long time. In the combat theater, they left the Patriot systems up and running for long times without rebooting the computer, so the clock error kept getting bigger. None of the tests you proposed would've found that error.

The newer PAC-III version of the missile uses kinetic energy to destroy the target and they've resolved the clock issue. It has been tested against Scud and Scud-like missiles and proved accurate in 2003.