BOOST_CHECK_EQUAL( gt.selectedTracks().size(), 0 );
gt.appendSelectedTrack(0, 0, seq0.size());
gt.appendSelectedTrack(2, 0, seq2.size());
BOOST_CHECK_EQUAL( gt.selectedTracks().size(), 0 );
gt.appendSelectedTrack(0, 0, seq0.size());
gt.appendSelectedTrack(2, 0, seq2.size());