### Question:
Person { @SuppressWarnings("NonFinalFieldReferencedInHashCode") @Override public int hashCode() { return Objects.hashCode(id, firstName, lastName, birthday); }  String getId(); void setId(final String id); String getFirstName(); void setFirstName(final String firstName); String getLastName(); void setLastName(final String lastName); LocalDate getBirthday(); void setBirthday(final LocalDate birthday); @SuppressWarnings("NonFinalFieldReferenceInEquals") @Override boolean equals(final Object o); @SuppressWarnings("NonFinalFieldReferencedInHashCode") @Override int hashCode(); @Override String toString();  }### Answer:
@Test public void testHashCode() { assertThat(person.hashCode()).isNotEqualTo(other.hashCode()); assertThat(person.hashCode()).isNotEqualTo(null); assertThat(person.hashCode()).isEqualTo(person.hashCode()); }