### Question:
Stat implements Stats { @Override public long sum() { return sum; } Stat(); void addStat(long stat); @Override long min(); @Override long max(); @Override long sum(); @Override double mean(); @Override String toString(); void clear(); @Override long num(); Stat copy();  }### Answer:
@Test public void testGetSum() { assertEquals(0, zero.sum()); assertEquals(38703, stat.sum()); }