Add explicit tests for position and cpid in track_to_mpd_format
Add explicit tests for position and cpid in track_to_mpd_format

ali/mopidy,dbrgn/mopidy,bacontext/mopidy,glogiotatidis/mopidy,rawdlite/mopidy,mokieyue/mopidy,kingosticks/mopidy,mokieyue/mopidy,tkem/mopidy,diandiankan/mopidy,priestd09/mopidy,pacificIT/mopidy,glogiotatidis/mopidy,liamw9534/mopidy,adamcik/mopidy,jmarsik/mopidy,pacificIT/mopidy,swak/mopidy,jodal/mopidy,dbrgn/mopidy,dbrgn/mopidy,tkem/mopidy,jmarsik/mopidy,mopidy/mopidy,liamw9534/mopidy,SuperStarPL/mopidy,jcass77/mopidy,jodal/mopidy,ZenithDK/mopidy,mopidy/mopidy,bacontext/mopidy,vrs01/mopidy,mopidy/mopidy,tkem/mopidy,quartz55/mopidy,priestd09/mopidy,bencevans/mopidy,adamcik/mopidy,bacontext/mopidy,pacificIT/mopidy,hkariti/mopidy,jcass77/mopidy,rawdlite/mopidy,mokieyue/mopidy,kingosticks/mopidy,vrs01/mopidy,jmarsik/mopidy,dbrgn/mopidy,bencevans/mopidy,glogiotatidis/mopidy,woutervanwijk/mopidy,quartz55/mopidy,quartz55/mopidy,jcass77/mopidy,ZenithDK/mopidy,bacontext/mopidy,hkariti/mopidy,bencevans/mopidy,SuperStarPL/mopidy,rawdlite/mopidy,woutervanwijk/mopidy,SuperStarPL/mopidy,ZenithDK/mopidy,pacificIT/mopidy,jmarsik/mopidy,quartz55/mopidy,ali/mopidy,vrs01/mopidy,diandiankan/mopidy,diandiankan/mopidy,hkariti/mopidy,priestd09/mopidy,bencevans/mopidy,swak/mopidy,jodal/mopidy,swak/mopidy,adamcik/mopidy,abarisain/mopidy,vrs01/mopidy,hkariti/mopidy,ali/mopidy,abarisain/mopidy,kingosticks/mopidy,rawdlite/mopidy,mokieyue/mopidy,diandiankan/mopidy,tkem/mopidy,swak/mopidy,SuperStarPL/mopidy,ali/mopidy,ZenithDK/mopidy,glogiotatidis/mopidy