I think this is all a big guess on your part.
Sure, I 'guess' that Apple uses standard industry processes for design, development, and testing of their products, just like everyone else in the technology industry, and virtually every other industry. Maybe, just maybe, their processes are even leading in the technology industry allowing them produce some of the most popular devices on the planet. Maybe, just maybe, they actually know everything there is to know about the product that they created.
And sure, I 'guess' that Apple is using advanced automated tools for design, development and testing. Sure, my 'guess' might be wrong, Apple could be using a million monkeys to develop or test the features on the latest device.