private void verifyBalanceSplit(final List<Pair<SnapshotFileInfo, Long>> split,
    final String[] expected, final long expectedSize) {
    assertEquals(expected.length, split.size());
    long totalSize = 0;
    for (int i = 0; i < expected.length; ++i) {
      Pair<SnapshotFileInfo, Long> fileInfo = split.get(i);
      assertEquals(expected[i], fileInfo.getFirst().getHfile());
      totalSize += fileInfo.getSecond();
    }
    assertEquals(expectedSize, totalSize);
  }
Verfy the result of getBalanceSplits() method. The result are groups of files, used as input
list for the "export" mappers. All the groups should have similar amount of data. The input
list is a pair of file path and length. The getBalanceSplits() function sort it by length, and
assign to each group a file, going back and forth through the groups.
hbase-mapreduce/src/test/java/org/apache/hadoop/hbase/snapshot/TestExportSnapshotHelpers.java