### Question:
Week extends RegularTimePeriod implements Serializable { @Override public long getSerialIndex() { return this.year * 53L + this.week; } Week();  Week(int week, int year);  Week(int week, Year year);  Week(Date time);  Week(Date time, TimeZone zone, Locale locale); Year getYear(); int getYearValue(); int getWeek(); @Override long getFirstMillisecond(); @Override long getLastMillisecond(); @Override void peg(Calendar calendar); @Override RegularTimePeriod previous(); @Override RegularTimePeriod next(); @Override long getSerialIndex(); @Override long getFirstMillisecond(Calendar calendar); @Override long getLastMillisecond(Calendar calendar); @Override String toString(); @Override boolean equals(Object obj); @Override int hashCode(); @Override int compareTo(TimePeriod o1); static Week parseWeek(String s); static final int FIRST_WEEK_IN_YEAR; static final int LAST_WEEK_IN_YEAR; }### Answer:
@Test public void testGetSerialIndex() { Week w = new Week(1, 2000); assertEquals(106001L, w.getSerialIndex()); w = new Week(1, 1900); assertEquals(100701L, w.getSerialIndex()); }