private static RegionInfo createMockRegionInfo(TableName table, int storeFileSizeMb) {
    long regionId = new Random().nextLong();
    REGION_TO_STORE_FILE_SIZE_MB.put(regionId, storeFileSizeMb);
    return RegionInfoBuilder.newBuilder(table).setStartKey(generateRandomByteArray(4))
      .setEndKey(generateRandomByteArray(4)).setReplicaId(0).setRegionId(regionId).build();
  }
Helper method to create a RegionInfo for a specified table with the given store file size.
hbase-balancer/src/test/java/org/apache/hadoop/hbase/master/balancer/TestStoreFileTableSkewCostFunction.java