Validations extends HashSet<Validation> { public static ValidationsBuilder builder() { return new ValidationsBuilder(); } private  Validations(); static ValidationBuilder single(); static ValidationsBuilder builder(); boolean allowsUnrecognizedPaths(); Set<String> getOwnValidatingPaths();  }
@Test public void testAllowEmpty() { Validations v = Validations.builder() .mandatoryPath("mandatory") .allowEmptyValue("mandatory") .build(); assertEquals(1, v.size()); assertTrue(v.iterator().next() instanceof MandatoryPathValidation); }