Messages App in iOS simulator? I know that there exists an iOS simulator for Mac (how to get it eludes me - if you could give me a download link I'd be grateful).

Many people want to know how to use multiple Apple IDs with Messages.  Can I use the Messages app inside the iOS simulator to run a second Apple ID?

Mac OS X 10.11.2
2011 Mac  Mini
No, you can't.  The Messages app is actually in Xcode, the Apple development environment.  Within Xcode are the iPhone, iPad, and Mac simulators.  Apple prevents the simulators from sending actual messages.  I have created iOS apps that send messages so I've tried doing this many, many times.  Each time you try to send a message you'll receive an error stating Cannot Send Message.