Someone just asked this question, if it was possible to get test messages destined for one phone number, sent to another device.
I have a Verizon smart phone, and two Verizon tablets, and one B&N WiFi-only tablet, all running Message+. Text messages sent to the smart phone appear on ALL four devices, and I can reply on any of them.
That's EXACTLY why I use Message+. I believe that Hangouts does the same thing, but I have personally tried it in this mode,
It's really unfortunate to answer incorrectly, and then lock the thread.