CalendarSyncer { private void enableSync() { if (!syncEnabled) { calendarAccessor.enableSync(calendarId); syncEnabled = true; } } CalendarSyncer(CalendarAccessor calendarAccessor,
                   long calendarId,
                   PersonLookup personLookup,
                   CallFormatter callFormatter); void syncCalendar(ConversionResult result);  }
@Test public void shouldEnableSync() throws Exception { shouldSyncCalendar(); verify(accessor).enableSync(CALENDAR_ID); }
@Test public void shouldOnlyEnableSyncOnce() throws Exception { shouldSyncCalendar(); reset(accessor); shouldSyncCalendar(); verify(accessor, never()).enableSync(CALENDAR_ID); }