A friend at Apple told me that the testing story for iOS is complete shit, and they actually rely on hundreds of humans to test their software to make up for poor automated testing.
Apple takes the approach of throwing humans instead of automation at a problem quite frequently [1]:
> The press release mentions RMSI, an India-based, geospatial data firm that creates vegetation and 3D building datasets. And the office’s large headcount (now near 5,000) [used to create Apple Maps]
The lack of automated testing is something Apple is working on fixing, but they're a ways away from having anything substantial. The terrible iOS 13 release quite significantly bumped up the internal priority of stability and testing. iOS 14 is likely to be far less buggy than iOS 13 because of this culture change.
Apple takes the approach of throwing humans instead of automation at a problem quite frequently [1]:
> The press release mentions RMSI, an India-based, geospatial data firm that creates vegetation and 3D building datasets. And the office’s large headcount (now near 5,000) [used to create Apple Maps]
The lack of automated testing is something Apple is working on fixing, but they're a ways away from having anything substantial. The terrible iOS 13 release quite significantly bumped up the internal priority of stability and testing. iOS 14 is likely to be far less buggy than iOS 13 because of this culture change.
[1]: https://www.justinobeirne.com/new-apple-maps