Since country X doesn’t want other nations thinking it’s starting a war when testing a ballistic missile or going through a military exercise or detonating a nuclear weapon, how does it go about informing other nations that this is just a test? What do other nations do to prepare in case country X is lying and it really is the opening shot of a sneak attack?
If I may take to liberty of offering some observations and speculations (a.k.a. “talking out of one’s ass”) rather than genuine factual diplomatic information:
The second part of your question (how would other nations know how to take the announcement?) can depend on the level of military intelligence available; some knowledge of the other nation’s capabilities; and sometimes, the general level of international tensions and hysteria gets involved.
Let me speak of the 1960’s, a tense time in the Cold War, when there was some widespread hyped-up hysteria that the Godless Commies might try to nuke us at any time. Cooler heads in higher diplomatic places might have known better, but the demagogues did their best to keep the public in a state in incipient terror, with some degree of success.
We had “civil defense” tests every month, at well-known scheduled times, when the city would blow those sirens. Even in the 1960’s, 20 years after WWII, we still called these “air raid” sirens.
As an eminently logical-minded young child in those days, I wondered: Wouldn’t it be the LOGICAL things for the Russians to do, to nuke us at the time of our scheduled tests, when we would all be off-guard, “knowing” that it’s just a test? After all, we the general public didn’t all go rushing to our air raid shelters every month when those horns blew! We became complacent sitting ducks during those moments.
Well, it really did get tense for a few days during the so-called “Cuban Missile Crisis”. People panicked. Even out in Sunny California, at the far end of the nation, underground Bomb Shelters were big business. We had neighbors on our block who installed one. One day my mother came home from shopping and announced that the shelves at the supermarket were bare! Such was the public panic.
Fast forward to 2012. North Korea announces (for the several[sup]th[/sup] time) that they’re going to test a missile or a nuke or whatever. The “major powers” huff and puff and splutter, but nobody seems to think it’s anything very serious. Ha! Those North Korean clowns can’t even make the trains run on time! (Do they even have trains in North Korea?)
So a lot of it does seem to depend on just what the “global community” thinks one nation is up to, or what they are capable of.
There are agreements between states for example between the United States and the FSU (and I suspect now Russia) or between Pakistan and India. More practically it would be done because it is in the interests of the testing country that it is not construed as a prelude to an attack as this incident shows.
I suspect that information is given as to the location, timing, trajectory and target of the launch.
For countries that are real threats, we have ways of knowing what’s going on in that country. Do you think we are not keeping tabs on places like North Korea on a normal basis? This involves several different alphabet-soup government/military agencies, and you won’t find/get much more detailed info as to how we determine these things.
To answer the OP: I’d imagine a quick call/email/text or fax to the air attache at the relevent embassies would do the trick.
I strongly doubt it. There are much more stringent protocols.