Also promises to the other party that “Don’t worry, this is all just a drill.”

Okay, but given that the army hasn't attacked anyone as of right now, what term would you consider appropriate to describe the "drills"?

There is a term for this: mobilization. It's a bit more dramatic, of course, in wars past, but the concept remains the same:

> Poland partly mobilized its troops on August 24, 1939, and fully mobilized on August 30, 1939, following the increased confrontations with Germany since March 1939. On September 1, 1939 Germany invaded Poland, which prompted both France and Britain to declare war on Germany.

> On 30 August, the Polish Navy sent its destroyer flotilla to Britain, executing the Peking Plan. On the same day, Marshal of Poland Edward Rydz-Śmigły announced the mobilization of Polish troops. However, he was pressured into revoking the order by the French, who apparently still hoped for a diplomatic settlement, failing to realize that the Germans were fully mobilized and concentrated at the Polish border.