anchor.diff:  start_device( Server, Configuration ) ->
   	gen_server:call( Server, { start_device, Configuration } ).
   
  --spec stop_device( pid(), device_id() ) -> ok.
  +-spec stop_device( pid(), device_id() ) -> ok | { error | no_such_device }.
   stop_device( Server, Id ) ->
   	gen_server:call( Server, { stop_device, Id } ).
   
  
positive.code: 	meck:new( lurch_driver_port, [ ] ),
  	meck:expect( lurch_driver_port, start_driver,
  				 fun( _Driver, _Parameters ) -> { ok, port_mock } end ),
  	Pid.
  
  
  
negative.code: 	end.
  
  
  device_to_proplist( Device ) ->
  	[ { id, Device#device.id }
  	, { driver, Device#device.driver }
  