@Test
public void testConvertValue() throws Exception {

    MaskLeavingLastFourDigitStandardizer cc = MaskLeavingLastFourDigitStandardizer.instance();
    assertEquals("XXXXXXXXXXXX8790", cc.convertValue("5100145505218790"));
    assertEquals("XXXX-XXXX-XXXX-8790", cc.convertValue("5100-1455-0521-8790"));
    assertEquals("XXX-XX-2015", cc.convertValue("560-60-2015"));
    assertEquals("2015", cc.convertValue("2015"));
    assertEquals("20", cc.convertValue("20"));
    assertEquals("", cc.convertValue(""));
    assertEquals("XXXXXXXXXXX9966", cc.convertValue("373327123279966"));
}