### Question:
HistogramStats extends AbstractStats { @Override public Stats add(Number value) { Validate.notNull(value, "value must not be null"); Validate.isTrue(value instanceof Integer, "value must be an Integer"); add(value.intValue(), 1); return this; } HistogramStats(int maxValue);  HistogramStats(); @Override Stats add(Number value); Stats add(int value, int times); @Override double getMean(); @Override double getStandardDeviation(); @Override double getPercentile(int p); @Override int getCount(); @Override double getMin(); @Override double getMax(); @Override double getSum(); @Override double getMse(); @Override double getCumulativeProbability(double t); @Override double getMode(); void iterate(IntConsumer consumer); double getSkewness(); double getKurtosis(); @Override boolean isSample();  }### Answer:
@Test public void testEdgeCases() { HistogramStats stats = new HistogramStats(3); stats.add(1, 10); assertEquals(0, stats.getVariance(), DELTA); }