Question: I have XCode 8.3.3., and testing an app that makes REST API calls. When open another app in foreground ( some of the stock simulator apps: calendar, news, etc. ), my app still continues to make periodic REST calls. This is not what happens on the real device (iPhone 5S). It makes the calls, even if I Lock my simulator out.

Is this intended behavior? How can I get real device compliance?
Thanks.

Answer: 
Good news: As of Xcode 9 Beta 3 we suspend background processes in the Simulator.
The question is answered in the comments. 

Basically XCode simulator doesn't enforce background tasks.