### Question:
Stat implements Stats { public void clear() { min = Long.MAX_VALUE; max = Long.MIN_VALUE; sum = 0; mean.clear(); } 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 testClear() { zero.clear(); stat.clear(); assertEquals(0, zero.max()); assertEquals(zero.max(), stat.max()); assertEquals(0, zero.min()); assertEquals(zero.min(), stat.min()); assertEquals(0, zero.sum()); assertEquals(zero.sum(), stat.sum()); assertEquals(Double.NaN, zero.mean(), 0); assertEquals(zero.mean(), stat.mean(), 0); }