tests: parametrized next and previous track tests.
tests: parametrized next and previous track tests.

adamcik/mopidy,mopidy/mopidy,jodal/mopidy,kingosticks/mopidy,adamcik/mopidy,jodal/mopidy,kingosticks/mopidy,jcass77/mopidy,mopidy/mopidy,jodal/mopidy,mopidy/mopidy,adamcik/mopidy,kingosticks/mopidy,jcass77/mopidy,jcass77/mopidy