@Override
  public void setBigNumber( BigDecimal number ) {
    string = number.toString();
  }
@Test
  public void testSetBigNumber() {
    ValueString vs = new ValueString();

    try {
      vs.setBigNumber( null );
      // assertNull(vs.getString());
      fail( "expected NullPointerException" );
    } catch ( NullPointerException ex ) {
      // This is the original behaviour
    }

    vs.setBigNumber( BigDecimal.ZERO );
    assertEquals( "0", vs.getString() );
  }