UrlValueConverter extends AbstractValueConverter<URL> { @Override public String toString(URL value) { if (value == null) { return null; } return value.toString(); } private  UrlValueConverter(); @Override URL convert(String s); @Override String toString(URL value); @Override String toSafeString(URL value); static final ValueConverter<URL> INSTANCE; }
@Test public void testToStringNull() throws Exception { assertThat(converter.toString(null)).isNull(); }