private CombinedDataSource getDataSource(CombinedDataSource.Operation operation){
String pathA = TestUtils.DATA_DIR + "seg/toCombine_a.seg";
String pathB = TestUtils.DATA_DIR + "seg/toCombine_b.seg";
SegmentedDataSet dsA = getSegDataSet(pathA);
SegmentedDataSet dsB = getSegDataSet(pathB);
SegmentedDataSource sourceA = new SegmentedDataSource("0123-A", dsA);
SegmentedDataSource sourceB = new SegmentedDataSource("0123-B-1", dsB);
DataSourceTrack trackA = new DataSourceTrack(null, sourceA.getTrackIdentifier(), sourceA.getTrackIdentifier(), sourceA);