add a test case for PositionTracking::clearTrack()
add a test case for PositionTracking::clearTrack()

David-Gil/marble-dev,quannt24/marble,tucnak/marble,tucnak/marble,oberluz/marble,tzapzoor/marble,rku/marble,rku/marble,AndreiDuma/marble,quannt24/marble,tzapzoor/marble,Earthwings/marble,oberluz/marble,Earthwings/marble,utkuaydin/marble,AndreiDuma/marble,utkuaydin/marble,David-Gil/marble-dev,AndreiDuma/marble,adraghici/marble,rku/marble,rku/marble,David-Gil/marble-dev,David-Gil/marble-dev,quannt24/marble,probonopd/marble,tzapzoor/marble,utkuaydin/marble,tucnak/marble,probonopd/marble,tucnak/marble,tucnak/marble,quannt24/marble,probonopd/marble,oberluz/marble,probonopd/marble,AndreiDuma/marble,David-Gil/marble-dev,AndreiDuma/marble,oberluz/marble,oberluz/marble,Earthwings/marble,Earthwings/marble,quannt24/marble,tzapzoor/marble,tucnak/marble,tzapzoor/marble,adraghici/marble,David-Gil/marble-dev,adraghici/marble,probonopd/marble,Earthwings/marble,utkuaydin/marble,tzapzoor/marble,tzapzoor/marble,Earthwings/marble,oberluz/marble,tzapzoor/marble,utkuaydin/marble,rku/marble,adraghici/marble,probonopd/marble,quannt24/marble,tucnak/marble,probonopd/marble,utkuaydin/marble,quannt24/marble,adraghici/marble,adraghici/marble,AndreiDuma/marble,rku/marble