@Test
public void testAppendToConf() {

  final int expectedBlocksPerChunk = 999;
  final String expectedValForEmptyConfigKey = "VALUE_OF_EMPTY_CONFIG_KEY";
  DistCpOptions options = new DistCpOptions.Builder(
      Collections.singletonList(
          new Path("hdfs://localhost:8020/source")),
      new Path("hdfs://localhost:8020/target/"))
      .withBlocksPerChunk(expectedBlocksPerChunk)
      .build();
  Configuration config = new Configuration();
  config.set("", expectedValForEmptyConfigKey);
  options.appendToConf(config);
  Assert.assertEquals(expectedBlocksPerChunk,
      config.getInt(
          DistCpOptionSwitch
              .BLOCKS_PER_CHUNK
              .getConfigLabel(), 0));
  Assert.assertEquals(
      "Some DistCpOptionSwitch's config label is empty! " +
          "Pls ensure the config label is provided when apply to config, " +
          "otherwise it may not be fetched properly",
          expectedValForEmptyConfigKey, config.get(""));
}