### Question:
NewIdentityCreator { public int createNewStreetNumber(Person person) { return person.getAddress().getStreetNumber() + 5; }  String createNewName(Person person); int createNewStreetNumber(Person person); List<Person> createNewSiblings(Person person);  }### Answer:
@Test public void should_generate_new_street_number() { Person person = createPersonWithStreetNumber(10); int newStreetNumber = systemUnderTest.createNewStreetNumber(person); then(newStreetNumber).isNotEqualTo(person.getAddress().getStreetNumber()); }