Arduino Simulator/Emulator for Mac OSx?

I'd like to create/debug code on my Mac Book without having to connect my Uno (which is currently connected to some circuitry). I also don't want to have to load a Windows emulator. Is there a good simulator that runs on OSx? Any that I've found so far only run on Windows.

I went through the same thing myself and ended up deciding that the best Arduino simulator is just another Arduino. Especially an Uno which isn't very expensive.

ALthough simulator would be nice, I decided to use a Nano and Serial.print statements.

There is http://123d.circuits.io It's free and simulates. Not perfect but good enough.