### Question:
DefaultCalendarEra extends AbstractIdentifiedObject implements CalendarEra { public void setReferenceEvent(final InternationalString referenceEvent) { ArgumentChecks.ensureNonNull("referenceEvent", referenceEvent); this.referenceEvent = referenceEvent; } DefaultCalendarEra(Map<String, ?> properties,
            final CalendarDate referenceDate, final JulianDate julianReference, final Period epochOfUse); private  DefaultCalendarEra(); private  DefaultCalendarEra(final CalendarEra object); static DefaultCalendarEra castOrCopy(final CalendarEra object); @Override @XmlElement(name = "referenceEvent", required = true) InternationalString getReferenceEvent(); @Override CalendarDate getReferenceDate(); @Override JulianDate getJulianReference(); @Override @XmlElement(name = "epochOfUse", required = true) Period getEpochOfUse(); Collection<Calendar> getDatingSystem(); void setReferenceEvent(final InternationalString referenceEvent); void setReferenceDate(final CalendarDate referenceDate); void setJulianReference(final JulianDate julianReference); void setEpochOfUse(final Period epochOfUse); void setDatingSystem(final Collection<Calendar> newValues); @Override boolean equals(Object object, ComparisonMode mode); @Override String toString();  }### Answer:
@Test public void testSetReferenceEvent() { InternationalString result = calendarEra1.getReferenceEvent(); ((DefaultCalendarEra)calendarEra1).setReferenceEvent(new SimpleInternationalString("new Era description")); assertFalse(calendarEra1.getReferenceEvent().equals(result)); }