How did the USSR prepare for the Second World War?

The USSR was preparing for a war with Nazi Germany. New tanks and aircraft were invented and manufactured, superior to the German ones, the movement of troops to the western border began, but …
The Molotov-Ribentrop Pact lived the beginning of a short friendship between two future adversaries. Stalin turned a blind eye to provocations from Germany and did not supply the Germans with raw materials and equipment. The preparation to repel the German attack was suspended. In general, before that there was a theory of war with little blood and on foreign territory, but none of this, as history shows, came of it.