@Override
    public String convertTo(SortedSet<Path> value) {
        if (value == null) {
            throw new ParameterException("String list of Paths must not be null.");
        }

        return value.stream().map(Path::toString).collect(Collectors.joining(","));
    }
@Test
    public void testConvertToEmpty() {
        assertEquals("", converter.convertTo(new TreeSet<>()));
    }