long offset() {
    return new OffsetParam(param(OffsetParam.NAME)).getOffset();
  }
@Test
  public void testOffset() throws IOException {
    final long X = 42;

    long offset = new OffsetParam(Long.toString(X)).getOffset();
    Assert.assertEquals("OffsetParam: ", X, offset);

    offset = new OffsetParam((String) null).getOffset();
    Assert.assertEquals("OffsetParam with null should have defaulted to 0", 0, offset);

    try {
      offset = new OffsetParam("abc").getValue();
      Assert.fail("OffsetParam with nondigit value should have thrown IllegalArgumentException");
    } catch (IllegalArgumentException iae) {
      // Ignore
    }
  }