### Question:
PercentileDistributionSummary implements DistributionSummary { public double percentile(double p) { long[] counts = new long[PercentileBuckets.length()]; for (int i = 0; i < counts.length; ++i) { counts[i] = counterFor(i).count(); } return PercentileBuckets.percentile(counts, p); } private  PercentileDistributionSummary(Registry registry, Id id, long min, long max); private  PercentileDistributionSummary(
      Registry registry,
      Id id,
      long min,
      long max,
      AtomicReferenceArray<Counter> counters); static PercentileDistributionSummary get(Registry registry, Id id); static IdBuilder<Builder> builder(Registry registry); @Override Id id(); @Override Iterable<Measurement> measure(); @Override boolean hasExpired(); @Override void record(long amount); double percentile(double p); @Override long count(); @Override long totalAmount();  }### Answer:
@Test public void percentile() { Registry r = newRegistry(); PercentileDistributionSummary t = PercentileDistributionSummary.get(r, r.createId("test")); checkPercentiles(t, 0); }