@Udf
  public Long round(@UdfParameter final long val) {
    return val;
  }
@Test
  public void shoulldHandleNullValues() {
    assertThat(udf.round((Double)null), is((Long)null));
    assertThat(udf.round((BigDecimal) null), is((BigDecimal) null));
    assertThat(udf.round((Double)null, 2), is((Long)null));
    assertThat(udf.round((BigDecimal) null, 2), is((BigDecimal) null));
  }