Marionette's Emulator class allows tests to interact with an emulator.  For tests run on an emulator, an Emulator instance is available as self.marionette.emulator.
Implementation: https://github.com/mozilla/marionett...te/emulator.py
Attributes
| Attribute | Type | Description | 
| battery | EmulatorBattery | An instance of EmulatorBattery that tests can use to interact with the emulator's battery. | 
| is_running | bool | True if an emulator is currently running and attached to Marionette, otherwiseFalse. | 
| port | int | The emulator's adb telnet port number; this can be used as the phone number for calls or SMS targeted at this emulator. |