private List<RegionInfo> createTable(final TableName tableName) throws Exception {
    TableDescriptor desc = TableDescriptorBuilder.newBuilder(tableName)
      .setColumnFamily(ColumnFamilyDescriptorBuilder.of(FAMILY)).build();
    byte[][] splitRows = new byte[initialRegionCount - 1][];
    for (int i = 0; i < splitRows.length; ++i) {
      splitRows[i] = Bytes.toBytes(String.format("%d", i));
    }
    admin.createTable(desc, splitRows);
    return assertRegionCount(tableName, initialRegionCount);
  }
This tests two concurrent region merges
hbase-server/src/test/java/org/apache/hadoop/hbase/master/assignment/TestMergeTableRegionsProcedure.java